Merge branch 'zfsonlinux/merge-spl'

Merge a minimal version of the zfsonlinux/spl repository in to the
zfsonlinux/zfs repository.  Care was taken to prevent file conflicts
when merging and to preserve the spl repository history.  The spl
kernel module remains under the GPLv2 license as documented by the
additional THIRDPARTYLICENSE.gplv2 file.

Signed-off-by: Brian Behlendorf <[email protected]>

21 files changed, 9806 insertions, 0 deletions

diff --git a/module/spl/THIRDPARTYLICENSE.gplv2 b/module/spl/THIRDPARTYLICENSE.gplv2
new file mode 100644
index 000000000..d159169d1
--- /dev/null
+++ b/module/spl/THIRDPARTYLICENSE.gplv2
@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
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+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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+
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+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
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+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
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+    You should have received a copy of the GNU General Public License along
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+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
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+The hypothetical commands `show w' and `show c' should show the appropriate
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+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
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+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
diff --git a/module/spl/THIRDPARTYLICENSE.gplv2.descrip b/module/spl/THIRDPARTYLICENSE.gplv2.descrip
new file mode 100644
index 000000000..78535a8ee
--- /dev/null
+++ b/module/spl/THIRDPARTYLICENSE.gplv2.descrip
@@ -0,0 +1 @@
+COMPATIBILITY LAYER FOR OPENZFS ON LINUX
diff --git a/module/spl/spl-atomic.c b/module/spl/spl-atomic.c
new file mode 100644
index 000000000..47ed1886e
--- /dev/null
+++ b/module/spl/spl-atomic.c
@@ -0,0 +1,36 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Atomic Implementation.
+ */
+
+#include <sys/atomic.h>
+
+#ifdef ATOMIC_SPINLOCK
+/* Global atomic lock declarations */
+DEFINE_SPINLOCK(atomic32_lock);
+DEFINE_SPINLOCK(atomic64_lock);
+
+EXPORT_SYMBOL(atomic32_lock);
+EXPORT_SYMBOL(atomic64_lock);
+#endif /* ATOMIC_SPINLOCK */
diff --git a/module/spl/spl-condvar.c b/module/spl/spl-condvar.c
new file mode 100644
index 000000000..f0060bbdc
--- /dev/null
+++ b/module/spl/spl-condvar.c
@@ -0,0 +1,410 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Credential Implementation.
+ */
+
+#include <sys/condvar.h>
+#include <sys/time.h>
+#include <linux/hrtimer.h>
+
+void
+__cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg)
+{
+	ASSERT(cvp);
+	ASSERT(name == NULL);
+	ASSERT(type == CV_DEFAULT);
+	ASSERT(arg == NULL);
+
+	cvp->cv_magic = CV_MAGIC;
+	init_waitqueue_head(&cvp->cv_event);
+	init_waitqueue_head(&cvp->cv_destroy);
+	atomic_set(&cvp->cv_waiters, 0);
+	atomic_set(&cvp->cv_refs, 1);
+	cvp->cv_mutex = NULL;
+}
+EXPORT_SYMBOL(__cv_init);
+
+static int
+cv_destroy_wakeup(kcondvar_t *cvp)
+{
+	if (!atomic_read(&cvp->cv_waiters) && !atomic_read(&cvp->cv_refs)) {
+		ASSERT(cvp->cv_mutex == NULL);
+		ASSERT(!waitqueue_active(&cvp->cv_event));
+		return (1);
+	}
+
+	return (0);
+}
+
+void
+__cv_destroy(kcondvar_t *cvp)
+{
+	ASSERT(cvp);
+	ASSERT(cvp->cv_magic == CV_MAGIC);
+
+	cvp->cv_magic = CV_DESTROY;
+	atomic_dec(&cvp->cv_refs);
+
+	/* Block until all waiters are woken and references dropped. */
+	while (cv_destroy_wakeup(cvp) == 0)
+		wait_event_timeout(cvp->cv_destroy, cv_destroy_wakeup(cvp), 1);
+
+	ASSERT3P(cvp->cv_mutex, ==, NULL);
+	ASSERT3S(atomic_read(&cvp->cv_refs), ==, 0);
+	ASSERT3S(atomic_read(&cvp->cv_waiters), ==, 0);
+	ASSERT3S(waitqueue_active(&cvp->cv_event), ==, 0);
+}
+EXPORT_SYMBOL(__cv_destroy);
+
+static void
+cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state, int io)
+{
+	DEFINE_WAIT(wait);
+	kmutex_t *m;
+
+	ASSERT(cvp);
+	ASSERT(mp);
+	ASSERT(cvp->cv_magic == CV_MAGIC);
+	ASSERT(mutex_owned(mp));
+	atomic_inc(&cvp->cv_refs);
+
+	m = ACCESS_ONCE(cvp->cv_mutex);
+	if (!m)
+		m = xchg(&cvp->cv_mutex, mp);
+	/* Ensure the same mutex is used by all callers */
+	ASSERT(m == NULL || m == mp);
+
+	prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
+	atomic_inc(&cvp->cv_waiters);
+
+	/*
+	 * Mutex should be dropped after prepare_to_wait() this
+	 * ensures we're linked in to the waiters list and avoids the
+	 * race where 'cvp->cv_waiters > 0' but the list is empty.
+	 */
+	mutex_exit(mp);
+	if (io)
+		io_schedule();
+	else
+		schedule();
+
+	/* No more waiters a different mutex could be used */
+	if (atomic_dec_and_test(&cvp->cv_waiters)) {
+		/*
+		 * This is set without any lock, so it's racy. But this is
+		 * just for debug anyway, so make it best-effort
+		 */
+		cvp->cv_mutex = NULL;
+		wake_up(&cvp->cv_destroy);
+	}
+
+	finish_wait(&cvp->cv_event, &wait);
+	atomic_dec(&cvp->cv_refs);
+
+	/*
+	 * Hold mutex after we release the cvp, otherwise we could dead lock
+	 * with a thread holding the mutex and call cv_destroy.
+	 */
+	mutex_enter(mp);
+}
+
+void
+__cv_wait(kcondvar_t *cvp, kmutex_t *mp)
+{
+	cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 0);
+}
+EXPORT_SYMBOL(__cv_wait);
+
+void
+__cv_wait_io(kcondvar_t *cvp, kmutex_t *mp)
+{
+	cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 1);
+}
+EXPORT_SYMBOL(__cv_wait_io);
+
+void
+__cv_wait_sig(kcondvar_t *cvp, kmutex_t *mp)
+{
+	cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0);
+}
+EXPORT_SYMBOL(__cv_wait_sig);
+
+#if defined(HAVE_IO_SCHEDULE_TIMEOUT)
+#define	spl_io_schedule_timeout(t)	io_schedule_timeout(t)
+#else
+static void
+__cv_wakeup(unsigned long data)
+{
+	wake_up_process((struct task_struct *)data);
+}
+
+static long
+spl_io_schedule_timeout(long time_left)
+{
+	long expire_time = jiffies + time_left;
+	struct timer_list timer;
+
+	init_timer(&timer);
+	setup_timer(&timer, __cv_wakeup, (unsigned long)current);
+	timer.expires = expire_time;
+	add_timer(&timer);
+
+	io_schedule();
+
+	del_timer_sync(&timer);
+	time_left = expire_time - jiffies;
+
+	return (time_left < 0 ? 0 : time_left);
+}
+#endif
+
+/*
+ * 'expire_time' argument is an absolute wall clock time in jiffies.
+ * Return value is time left (expire_time - now) or -1 if timeout occurred.
+ */
+static clock_t
+__cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time,
+    int state, int io)
+{
+	DEFINE_WAIT(wait);
+	kmutex_t *m;
+	clock_t time_left;
+
+	ASSERT(cvp);
+	ASSERT(mp);
+	ASSERT(cvp->cv_magic == CV_MAGIC);
+	ASSERT(mutex_owned(mp));
+
+	/* XXX - Does not handle jiffie wrap properly */
+	time_left = expire_time - jiffies;
+	if (time_left <= 0)
+		return (-1);
+
+	atomic_inc(&cvp->cv_refs);
+	m = ACCESS_ONCE(cvp->cv_mutex);
+	if (!m)
+		m = xchg(&cvp->cv_mutex, mp);
+	/* Ensure the same mutex is used by all callers */
+	ASSERT(m == NULL || m == mp);
+
+	prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
+	atomic_inc(&cvp->cv_waiters);
+
+	/*
+	 * Mutex should be dropped after prepare_to_wait() this
+	 * ensures we're linked in to the waiters list and avoids the
+	 * race where 'cvp->cv_waiters > 0' but the list is empty.
+	 */
+	mutex_exit(mp);
+	if (io)
+		time_left = spl_io_schedule_timeout(time_left);
+	else
+		time_left = schedule_timeout(time_left);
+
+	/* No more waiters a different mutex could be used */
+	if (atomic_dec_and_test(&cvp->cv_waiters)) {
+		/*
+		 * This is set without any lock, so it's racy. But this is
+		 * just for debug anyway, so make it best-effort
+		 */
+		cvp->cv_mutex = NULL;
+		wake_up(&cvp->cv_destroy);
+	}
+
+	finish_wait(&cvp->cv_event, &wait);
+	atomic_dec(&cvp->cv_refs);
+
+	/*
+	 * Hold mutex after we release the cvp, otherwise we could dead lock
+	 * with a thread holding the mutex and call cv_destroy.
+	 */
+	mutex_enter(mp);
+	return (time_left > 0 ? time_left : -1);
+}
+
+clock_t
+__cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
+{
+	return (__cv_timedwait_common(cvp, mp, exp_time,
+	    TASK_UNINTERRUPTIBLE, 0));
+}
+EXPORT_SYMBOL(__cv_timedwait);
+
+clock_t
+__cv_timedwait_io(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
+{
+	return (__cv_timedwait_common(cvp, mp, exp_time,
+	    TASK_UNINTERRUPTIBLE, 1));
+}
+EXPORT_SYMBOL(__cv_timedwait_io);
+
+clock_t
+__cv_timedwait_sig(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
+{
+	return (__cv_timedwait_common(cvp, mp, exp_time,
+	    TASK_INTERRUPTIBLE, 0));
+}
+EXPORT_SYMBOL(__cv_timedwait_sig);
+
+/*
+ * 'expire_time' argument is an absolute clock time in nanoseconds.
+ * Return value is time left (expire_time - now) or -1 if timeout occurred.
+ */
+static clock_t
+__cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t expire_time,
+    int state)
+{
+	DEFINE_WAIT(wait);
+	kmutex_t *m;
+	hrtime_t time_left;
+	ktime_t ktime_left;
+
+	ASSERT(cvp);
+	ASSERT(mp);
+	ASSERT(cvp->cv_magic == CV_MAGIC);
+	ASSERT(mutex_owned(mp));
+
+	time_left = expire_time - gethrtime();
+	if (time_left <= 0)
+		return (-1);
+
+	atomic_inc(&cvp->cv_refs);
+	m = ACCESS_ONCE(cvp->cv_mutex);
+	if (!m)
+		m = xchg(&cvp->cv_mutex, mp);
+	/* Ensure the same mutex is used by all callers */
+	ASSERT(m == NULL || m == mp);
+
+	prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
+	atomic_inc(&cvp->cv_waiters);
+
+	/*
+	 * Mutex should be dropped after prepare_to_wait() this
+	 * ensures we're linked in to the waiters list and avoids the
+	 * race where 'cvp->cv_waiters > 0' but the list is empty.
+	 */
+	mutex_exit(mp);
+	/*
+	 * Allow a 100 us range to give kernel an opportunity to coalesce
+	 * interrupts
+	 */
+	ktime_left = ktime_set(0, time_left);
+	schedule_hrtimeout_range(&ktime_left, 100 * NSEC_PER_USEC,
+	    HRTIMER_MODE_REL);
+
+	/* No more waiters a different mutex could be used */
+	if (atomic_dec_and_test(&cvp->cv_waiters)) {
+		/*
+		 * This is set without any lock, so it's racy. But this is
+		 * just for debug anyway, so make it best-effort
+		 */
+		cvp->cv_mutex = NULL;
+		wake_up(&cvp->cv_destroy);
+	}
+
+	finish_wait(&cvp->cv_event, &wait);
+	atomic_dec(&cvp->cv_refs);
+
+	mutex_enter(mp);
+	time_left = expire_time - gethrtime();
+	return (time_left > 0 ? NSEC_TO_TICK(time_left) : -1);
+}
+
+/*
+ * Compatibility wrapper for the cv_timedwait_hires() Illumos interface.
+ */
+static clock_t
+cv_timedwait_hires_common(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim,
+    hrtime_t res, int flag, int state)
+{
+	if (res > 1) {
+		/*
+		 * Align expiration to the specified resolution.
+		 */
+		if (flag & CALLOUT_FLAG_ROUNDUP)
+			tim += res - 1;
+		tim = (tim / res) * res;
+	}
+
+	if (!(flag & CALLOUT_FLAG_ABSOLUTE))
+		tim += gethrtime();
+
+	return (__cv_timedwait_hires(cvp, mp, tim, state));
+}
+
+clock_t
+cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim, hrtime_t res,
+    int flag)
+{
+	return (cv_timedwait_hires_common(cvp, mp, tim, res, flag,
+	    TASK_UNINTERRUPTIBLE));
+}
+EXPORT_SYMBOL(cv_timedwait_hires);
+
+clock_t
+cv_timedwait_sig_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim,
+    hrtime_t res, int flag)
+{
+	return (cv_timedwait_hires_common(cvp, mp, tim, res, flag,
+	    TASK_INTERRUPTIBLE));
+}
+EXPORT_SYMBOL(cv_timedwait_sig_hires);
+
+void
+__cv_signal(kcondvar_t *cvp)
+{
+	ASSERT(cvp);
+	ASSERT(cvp->cv_magic == CV_MAGIC);
+	atomic_inc(&cvp->cv_refs);
+
+	/*
+	 * All waiters are added with WQ_FLAG_EXCLUSIVE so only one
+	 * waiter will be set runable with each call to wake_up().
+	 * Additionally wake_up() holds a spin_lock assoicated with
+	 * the wait queue to ensure we don't race waking up processes.
+	 */
+	if (atomic_read(&cvp->cv_waiters) > 0)
+		wake_up(&cvp->cv_event);
+
+	atomic_dec(&cvp->cv_refs);
+}
+EXPORT_SYMBOL(__cv_signal);
+
+void
+__cv_broadcast(kcondvar_t *cvp)
+{
+	ASSERT(cvp);
+	ASSERT(cvp->cv_magic == CV_MAGIC);
+	atomic_inc(&cvp->cv_refs);
+
+	/*
+	 * Wake_up_all() will wake up all waiters even those which
+	 * have the WQ_FLAG_EXCLUSIVE flag set.
+	 */
+	if (atomic_read(&cvp->cv_waiters) > 0)
+		wake_up_all(&cvp->cv_event);
+
+	atomic_dec(&cvp->cv_refs);
+}
+EXPORT_SYMBOL(__cv_broadcast);
diff --git a/module/spl/spl-cred.c b/module/spl/spl-cred.c
new file mode 100644
index 000000000..ea3e903f9
--- /dev/null
+++ b/module/spl/spl-cred.c
@@ -0,0 +1,200 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Credential Implementation.
+ */
+
+#include <sys/cred.h>
+
+static int
+#ifdef HAVE_KUIDGID_T
+cr_groups_search(const struct group_info *group_info, kgid_t grp)
+#else
+cr_groups_search(const struct group_info *group_info, gid_t grp)
+#endif
+{
+	unsigned int left, right, mid;
+	int cmp;
+
+	if (!group_info)
+		return (0);
+
+	left = 0;
+	right = group_info->ngroups;
+	while (left < right) {
+		mid = (left + right) / 2;
+		cmp = KGID_TO_SGID(grp) -
+		    KGID_TO_SGID(GROUP_AT(group_info, mid));
+
+		if (cmp > 0)
+			left = mid + 1;
+		else if (cmp < 0)
+			right = mid;
+		else
+			return (1);
+	}
+	return (0);
+}
+
+/* Hold a reference on the credential */
+void
+crhold(cred_t *cr)
+{
+	(void) get_cred((const cred_t *)cr);
+}
+
+/* Free a reference on the credential */
+void
+crfree(cred_t *cr)
+{
+	put_cred((const cred_t *)cr);
+}
+
+/* Return the number of supplemental groups */
+int
+crgetngroups(const cred_t *cr)
+{
+	struct group_info *gi;
+	int rc;
+
+	gi = cr->group_info;
+	rc = gi->ngroups;
+#ifndef HAVE_GROUP_INFO_GID
+	/*
+	 * For Linux <= 4.8,
+	 * crgetgroups will only returns gi->blocks[0], which contains only
+	 * the first NGROUPS_PER_BLOCK groups.
+	 */
+	if (rc > NGROUPS_PER_BLOCK) {
+		WARN_ON_ONCE(1);
+		rc = NGROUPS_PER_BLOCK;
+	}
+#endif
+	return (rc);
+}
+
+/*
+ * Return an array of supplemental gids.  The returned address is safe
+ * to use as long as the caller has taken a reference with crhold().
+ *
+ * Linux 4.9 API change, group_info changed from 2d array via ->blocks to 1d
+ * array via ->gid.
+ */
+gid_t *
+crgetgroups(const cred_t *cr)
+{
+	struct group_info *gi;
+	gid_t *gids = NULL;
+
+	gi = cr->group_info;
+#ifdef HAVE_GROUP_INFO_GID
+	gids = KGIDP_TO_SGIDP(gi->gid);
+#else
+	if (gi->nblocks > 0)
+		gids = KGIDP_TO_SGIDP(gi->blocks[0]);
+#endif
+	return (gids);
+}
+
+/* Check if the passed gid is available in supplied credential. */
+int
+groupmember(gid_t gid, const cred_t *cr)
+{
+	struct group_info *gi;
+	int rc;
+
+	gi = cr->group_info;
+	rc = cr_groups_search(gi, SGID_TO_KGID(gid));
+
+	return (rc);
+}
+
+/* Return the effective user id */
+uid_t
+crgetuid(const cred_t *cr)
+{
+	return (KUID_TO_SUID(cr->euid));
+}
+
+/* Return the real user id */
+uid_t
+crgetruid(const cred_t *cr)
+{
+	return (KUID_TO_SUID(cr->uid));
+}
+
+/* Return the saved user id */
+uid_t
+crgetsuid(const cred_t *cr)
+{
+	return (KUID_TO_SUID(cr->suid));
+}
+
+/* Return the filesystem user id */
+uid_t
+crgetfsuid(const cred_t *cr)
+{
+	return (KUID_TO_SUID(cr->fsuid));
+}
+
+/* Return the effective group id */
+gid_t
+crgetgid(const cred_t *cr)
+{
+	return (KGID_TO_SGID(cr->egid));
+}
+
+/* Return the real group id */
+gid_t
+crgetrgid(const cred_t *cr)
+{
+	return (KGID_TO_SGID(cr->gid));
+}
+
+/* Return the saved group id */
+gid_t
+crgetsgid(const cred_t *cr)
+{
+	return (KGID_TO_SGID(cr->sgid));
+}
+
+/* Return the filesystem group id */
+gid_t
+crgetfsgid(const cred_t *cr)
+{
+	return (KGID_TO_SGID(cr->fsgid));
+}
+
+EXPORT_SYMBOL(crhold);
+EXPORT_SYMBOL(crfree);
+EXPORT_SYMBOL(crgetuid);
+EXPORT_SYMBOL(crgetruid);
+EXPORT_SYMBOL(crgetsuid);
+EXPORT_SYMBOL(crgetfsuid);
+EXPORT_SYMBOL(crgetgid);
+EXPORT_SYMBOL(crgetrgid);
+EXPORT_SYMBOL(crgetsgid);
+EXPORT_SYMBOL(crgetfsgid);
+EXPORT_SYMBOL(crgetngroups);
+EXPORT_SYMBOL(crgetgroups);
+EXPORT_SYMBOL(groupmember);
diff --git a/module/spl/spl-err.c b/module/spl/spl-err.c
new file mode 100644
index 000000000..6b71296e8
--- /dev/null
+++ b/module/spl/spl-err.c
@@ -0,0 +1,133 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Error Implementation.
+ */
+
+#include <sys/sysmacros.h>
+#include <sys/cmn_err.h>
+#include <linux/ratelimit.h>
+
+/*
+ * It is often useful to actually have the panic crash the node so you
+ * can then get notified of the event, get the crashdump for later
+ * analysis and other such goodies.
+ * But we would still default to the current default of not to do that.
+ */
+/* BEGIN CSTYLED */
+unsigned int spl_panic_halt;
+module_param(spl_panic_halt, uint, 0644);
+MODULE_PARM_DESC(spl_panic_halt, "Cause kernel panic on assertion failures");
+/* END CSTYLED */
+
+/*
+ * Limit the number of stack traces dumped to not more than 5 every
+ * 60 seconds to prevent denial-of-service attacks from debug code.
+ */
+DEFINE_RATELIMIT_STATE(dumpstack_ratelimit_state, 60 * HZ, 5);
+
+void
+spl_dumpstack(void)
+{
+	if (__ratelimit(&dumpstack_ratelimit_state)) {
+		printk("Showing stack for process %d\n", current->pid);
+		dump_stack();
+	}
+}
+EXPORT_SYMBOL(spl_dumpstack);
+
+int
+spl_panic(const char *file, const char *func, int line, const char *fmt, ...)
+{
+	const char *newfile;
+	char msg[MAXMSGLEN];
+	va_list ap;
+
+	newfile = strrchr(file, '/');
+	if (newfile != NULL)
+		newfile = newfile + 1;
+	else
+		newfile = file;
+
+	va_start(ap, fmt);
+	(void) vsnprintf(msg, sizeof (msg), fmt, ap);
+	va_end(ap);
+
+	printk(KERN_EMERG "%s", msg);
+	printk(KERN_EMERG "PANIC at %s:%d:%s()\n", newfile, line, func);
+	if (spl_panic_halt)
+		panic("%s", msg);
+
+	spl_dumpstack();
+
+	/* Halt the thread to facilitate further debugging */
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	while (1)
+		schedule();
+
+	/* Unreachable */
+	return (1);
+}
+EXPORT_SYMBOL(spl_panic);
+
+void
+vcmn_err(int ce, const char *fmt, va_list ap)
+{
+	char msg[MAXMSGLEN];
+
+	vsnprintf(msg, MAXMSGLEN - 1, fmt, ap);
+
+	switch (ce) {
+	case CE_IGNORE:
+		break;
+	case CE_CONT:
+		printk("%s", msg);
+		break;
+	case CE_NOTE:
+		printk(KERN_NOTICE "NOTICE: %s\n", msg);
+		break;
+	case CE_WARN:
+		printk(KERN_WARNING "WARNING: %s\n", msg);
+		break;
+	case CE_PANIC:
+		printk(KERN_EMERG "PANIC: %s\n", msg);
+		spl_dumpstack();
+
+		/* Halt the thread to facilitate further debugging */
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		while (1)
+			schedule();
+	}
+} /* vcmn_err() */
+EXPORT_SYMBOL(vcmn_err);
+
+void
+cmn_err(int ce, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	vcmn_err(ce, fmt, ap);
+	va_end(ap);
+} /* cmn_err() */
+EXPORT_SYMBOL(cmn_err);
diff --git a/module/spl/spl-generic.c b/module/spl/spl-generic.c
new file mode 100644
index 000000000..b38fe254c
--- /dev/null
+++ b/module/spl/spl-generic.c
@@ -0,0 +1,775 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Generic Implementation.
+ */
+
+#include <sys/sysmacros.h>
+#include <sys/systeminfo.h>
+#include <sys/vmsystm.h>
+#include <sys/kobj.h>
+#include <sys/kmem.h>
+#include <sys/kmem_cache.h>
+#include <sys/vmem.h>
+#include <sys/mutex.h>
+#include <sys/rwlock.h>
+#include <sys/taskq.h>
+#include <sys/tsd.h>
+#include <sys/zmod.h>
+#include <sys/debug.h>
+#include <sys/proc.h>
+#include <sys/kstat.h>
+#include <sys/file.h>
+#include <linux/ctype.h>
+#include <sys/disp.h>
+#include <sys/random.h>
+#include <sys/strings.h>
+#include <linux/kmod.h>
+
+char spl_version[32] = "SPL v" SPL_META_VERSION "-" SPL_META_RELEASE;
+EXPORT_SYMBOL(spl_version);
+
+/* BEGIN CSTYLED */
+unsigned long spl_hostid = 0;
+EXPORT_SYMBOL(spl_hostid);
+module_param(spl_hostid, ulong, 0644);
+MODULE_PARM_DESC(spl_hostid, "The system hostid.");
+/* END CSTYLED */
+
+proc_t p0;
+EXPORT_SYMBOL(p0);
+
+/*
+ * Xorshift Pseudo Random Number Generator based on work by Sebastiano Vigna
+ *
+ * "Further scramblings of Marsaglia's xorshift generators"
+ * http://vigna.di.unimi.it/ftp/papers/xorshiftplus.pdf
+ *
+ * random_get_pseudo_bytes() is an API function on Illumos whose sole purpose
+ * is to provide bytes containing random numbers. It is mapped to /dev/urandom
+ * on Illumos, which uses a "FIPS 186-2 algorithm". No user of the SPL's
+ * random_get_pseudo_bytes() needs bytes that are of cryptographic quality, so
+ * we can implement it using a fast PRNG that we seed using Linux' actual
+ * equivalent to random_get_pseudo_bytes(). We do this by providing each CPU
+ * with an independent seed so that all calls to random_get_pseudo_bytes() are
+ * free of atomic instructions.
+ *
+ * A consequence of using a fast PRNG is that using random_get_pseudo_bytes()
+ * to generate words larger than 128 bits will paradoxically be limited to
+ * `2^128 - 1` possibilities. This is because we have a sequence of `2^128 - 1`
+ * 128-bit words and selecting the first will implicitly select the second. If
+ * a caller finds this behavior undesireable, random_get_bytes() should be used
+ * instead.
+ *
+ * XXX: Linux interrupt handlers that trigger within the critical section
+ * formed by `s[1] = xp[1];` and `xp[0] = s[0];` and call this function will
+ * see the same numbers. Nothing in the code currently calls this in an
+ * interrupt handler, so this is considered to be okay. If that becomes a
+ * problem, we could create a set of per-cpu variables for interrupt handlers
+ * and use them when in_interrupt() from linux/preempt_mask.h evaluates to
+ * true.
+ */
+static DEFINE_PER_CPU(uint64_t[2], spl_pseudo_entropy);
+
+/*
+ * spl_rand_next()/spl_rand_jump() are copied from the following CC-0 licensed
+ * file:
+ *
+ * http://xorshift.di.unimi.it/xorshift128plus.c
+ */
+
+static inline uint64_t
+spl_rand_next(uint64_t *s)
+{
+	uint64_t s1 = s[0];
+	const uint64_t s0 = s[1];
+	s[0] = s0;
+	s1 ^= s1 << 23; // a
+	s[1] = s1 ^ s0 ^ (s1 >> 18) ^ (s0 >> 5); // b, c
+	return (s[1] + s0);
+}
+
+static inline void
+spl_rand_jump(uint64_t *s)
+{
+	static const uint64_t JUMP[] =
+	    { 0x8a5cd789635d2dff, 0x121fd2155c472f96 };
+
+	uint64_t s0 = 0;
+	uint64_t s1 = 0;
+	int i, b;
+	for (i = 0; i < sizeof (JUMP) / sizeof (*JUMP); i++)
+		for (b = 0; b < 64; b++) {
+			if (JUMP[i] & 1ULL << b) {
+				s0 ^= s[0];
+				s1 ^= s[1];
+			}
+			(void) spl_rand_next(s);
+		}
+
+	s[0] = s0;
+	s[1] = s1;
+}
+
+int
+random_get_pseudo_bytes(uint8_t *ptr, size_t len)
+{
+	uint64_t *xp, s[2];
+
+	ASSERT(ptr);
+
+	xp = get_cpu_var(spl_pseudo_entropy);
+
+	s[0] = xp[0];
+	s[1] = xp[1];
+
+	while (len) {
+		union {
+			uint64_t ui64;
+			uint8_t byte[sizeof (uint64_t)];
+		}entropy;
+		int i = MIN(len, sizeof (uint64_t));
+
+		len -= i;
+		entropy.ui64 = spl_rand_next(s);
+
+		while (i--)
+			*ptr++ = entropy.byte[i];
+	}
+
+	xp[0] = s[0];
+	xp[1] = s[1];
+
+	put_cpu_var(spl_pseudo_entropy);
+
+	return (0);
+}
+
+
+EXPORT_SYMBOL(random_get_pseudo_bytes);
+
+#if BITS_PER_LONG == 32
+/*
+ * Support 64/64 => 64 division on a 32-bit platform.  While the kernel
+ * provides a div64_u64() function for this we do not use it because the
+ * implementation is flawed.  There are cases which return incorrect
+ * results as late as linux-2.6.35.  Until this is fixed upstream the
+ * spl must provide its own implementation.
+ *
+ * This implementation is a slightly modified version of the algorithm
+ * proposed by the book 'Hacker's Delight'.  The original source can be
+ * found here and is available for use without restriction.
+ *
+ * http://www.hackersdelight.org/HDcode/newCode/divDouble.c
+ */
+
+/*
+ * Calculate number of leading of zeros for a 64-bit value.
+ */
+static int
+nlz64(uint64_t x)
+{
+	register int n = 0;
+
+	if (x == 0)
+		return (64);
+
+	if (x <= 0x00000000FFFFFFFFULL) { n = n + 32; x = x << 32; }
+	if (x <= 0x0000FFFFFFFFFFFFULL) { n = n + 16; x = x << 16; }
+	if (x <= 0x00FFFFFFFFFFFFFFULL) { n = n +  8; x = x <<  8; }
+	if (x <= 0x0FFFFFFFFFFFFFFFULL) { n = n +  4; x = x <<  4; }
+	if (x <= 0x3FFFFFFFFFFFFFFFULL) { n = n +  2; x = x <<  2; }
+	if (x <= 0x7FFFFFFFFFFFFFFFULL) { n = n +  1; }
+
+	return (n);
+}
+
+/*
+ * Newer kernels have a div_u64() function but we define our own
+ * to simplify portibility between kernel versions.
+ */
+static inline uint64_t
+__div_u64(uint64_t u, uint32_t v)
+{
+	(void) do_div(u, v);
+	return (u);
+}
+
+/*
+ * Implementation of 64-bit unsigned division for 32-bit machines.
+ *
+ * First the procedure takes care of the case in which the divisor is a
+ * 32-bit quantity. There are two subcases: (1) If the left half of the
+ * dividend is less than the divisor, one execution of do_div() is all that
+ * is required (overflow is not possible). (2) Otherwise it does two
+ * divisions, using the grade school method.
+ */
+uint64_t
+__udivdi3(uint64_t u, uint64_t v)
+{
+	uint64_t u0, u1, v1, q0, q1, k;
+	int n;
+
+	if (v >> 32 == 0) {			// If v < 2**32:
+		if (u >> 32 < v) {		// If u/v cannot overflow,
+			return (__div_u64(u, v)); // just do one division.
+		} else {			// If u/v would overflow:
+			u1 = u >> 32;		// Break u into two halves.
+			u0 = u & 0xFFFFFFFF;
+			q1 = __div_u64(u1, v);	// First quotient digit.
+			k  = u1 - q1 * v;	// First remainder, < v.
+			u0 += (k << 32);
+			q0 = __div_u64(u0, v);	// Seconds quotient digit.
+			return ((q1 << 32) + q0);
+		}
+	} else {				// If v >= 2**32:
+		n = nlz64(v);			// 0 <= n <= 31.
+		v1 = (v << n) >> 32;		// Normalize divisor, MSB is 1.
+		u1 = u >> 1;			// To ensure no overflow.
+		q1 = __div_u64(u1, v1);		// Get quotient from
+		q0 = (q1 << n) >> 31;		// Undo normalization and
+						// division of u by 2.
+		if (q0 != 0)			// Make q0 correct or
+			q0 = q0 - 1;		// too small by 1.
+		if ((u - q0 * v) >= v)
+			q0 = q0 + 1;		// Now q0 is correct.
+
+		return (q0);
+	}
+}
+EXPORT_SYMBOL(__udivdi3);
+
+/* BEGIN CSTYLED */
+#ifndef abs64
+#define	abs64(x)	({ uint64_t t = (x) >> 63; ((x) ^ t) - t; })
+#endif
+/* END CSTYLED */
+
+/*
+ * Implementation of 64-bit signed division for 32-bit machines.
+ */
+int64_t
+__divdi3(int64_t u, int64_t v)
+{
+	int64_t q, t;
+	q = __udivdi3(abs64(u), abs64(v));
+	t = (u ^ v) >> 63;	// If u, v have different
+	return ((q ^ t) - t);	// signs, negate q.
+}
+EXPORT_SYMBOL(__divdi3);
+
+/*
+ * Implementation of 64-bit unsigned modulo for 32-bit machines.
+ */
+uint64_t
+__umoddi3(uint64_t dividend, uint64_t divisor)
+{
+	return (dividend - (divisor * __udivdi3(dividend, divisor)));
+}
+EXPORT_SYMBOL(__umoddi3);
+
+/*
+ * Implementation of 64-bit unsigned division/modulo for 32-bit machines.
+ */
+uint64_t
+__udivmoddi4(uint64_t n, uint64_t d, uint64_t *r)
+{
+	uint64_t q = __udivdi3(n, d);
+	if (r)
+		*r = n - d * q;
+	return (q);
+}
+EXPORT_SYMBOL(__udivmoddi4);
+
+/*
+ * Implementation of 64-bit signed division/modulo for 32-bit machines.
+ */
+int64_t
+__divmoddi4(int64_t n, int64_t d, int64_t *r)
+{
+	int64_t q, rr;
+	boolean_t nn = B_FALSE;
+	boolean_t nd = B_FALSE;
+	if (n < 0) {
+		nn = B_TRUE;
+		n = -n;
+	}
+	if (d < 0) {
+		nd = B_TRUE;
+		d = -d;
+	}
+
+	q = __udivmoddi4(n, d, (uint64_t *)&rr);
+
+	if (nn != nd)
+		q = -q;
+	if (nn)
+		rr = -rr;
+	if (r)
+		*r = rr;
+	return (q);
+}
+EXPORT_SYMBOL(__divmoddi4);
+
+#if defined(__arm) || defined(__arm__)
+/*
+ * Implementation of 64-bit (un)signed division for 32-bit arm machines.
+ *
+ * Run-time ABI for the ARM Architecture (page 20).  A pair of (unsigned)
+ * long longs is returned in {{r0, r1}, {r2,r3}}, the quotient in {r0, r1},
+ * and the remainder in {r2, r3}.  The return type is specifically left
+ * set to 'void' to ensure the compiler does not overwrite these registers
+ * during the return.  All results are in registers as per ABI
+ */
+void
+__aeabi_uldivmod(uint64_t u, uint64_t v)
+{
+	uint64_t res;
+	uint64_t mod;
+
+	res = __udivdi3(u, v);
+	mod = __umoddi3(u, v);
+	{
+		register uint32_t r0 asm("r0") = (res & 0xFFFFFFFF);
+		register uint32_t r1 asm("r1") = (res >> 32);
+		register uint32_t r2 asm("r2") = (mod & 0xFFFFFFFF);
+		register uint32_t r3 asm("r3") = (mod >> 32);
+
+		/* BEGIN CSTYLED */
+		asm volatile(""
+		    : "+r"(r0), "+r"(r1), "+r"(r2),"+r"(r3)  /* output */
+		    : "r"(r0), "r"(r1), "r"(r2), "r"(r3));   /* input */
+		/* END CSTYLED */
+
+		return; /* r0; */
+	}
+}
+EXPORT_SYMBOL(__aeabi_uldivmod);
+
+void
+__aeabi_ldivmod(int64_t u, int64_t v)
+{
+	int64_t res;
+	uint64_t mod;
+
+	res =  __divdi3(u, v);
+	mod = __umoddi3(u, v);
+	{
+		register uint32_t r0 asm("r0") = (res & 0xFFFFFFFF);
+		register uint32_t r1 asm("r1") = (res >> 32);
+		register uint32_t r2 asm("r2") = (mod & 0xFFFFFFFF);
+		register uint32_t r3 asm("r3") = (mod >> 32);
+
+		/* BEGIN CSTYLED */
+		asm volatile(""
+		    : "+r"(r0), "+r"(r1), "+r"(r2),"+r"(r3)  /* output */
+		    : "r"(r0), "r"(r1), "r"(r2), "r"(r3));   /* input */
+		/* END CSTYLED */
+
+		return; /* r0; */
+	}
+}
+EXPORT_SYMBOL(__aeabi_ldivmod);
+#endif /* __arm || __arm__ */
+#endif /* BITS_PER_LONG */
+
+/*
+ * NOTE: The strtoxx behavior is solely based on my reading of the Solaris
+ * ddi_strtol(9F) man page.  I have not verified the behavior of these
+ * functions against their Solaris counterparts.  It is possible that I
+ * may have misinterpreted the man page or the man page is incorrect.
+ */
+int ddi_strtoul(const char *, char **, int, unsigned long *);
+int ddi_strtol(const char *, char **, int, long *);
+int ddi_strtoull(const char *, char **, int, unsigned long long *);
+int ddi_strtoll(const char *, char **, int, long long *);
+
+#define	define_ddi_strtoux(type, valtype)				\
+int ddi_strtou##type(const char *str, char **endptr,			\
+    int base, valtype *result)						\
+{									\
+	valtype last_value, value = 0;					\
+	char *ptr = (char *)str;					\
+	int flag = 1, digit;						\
+									\
+	if (strlen(ptr) == 0)						\
+		return (EINVAL);					\
+									\
+	/* Auto-detect base based on prefix */				\
+	if (!base) {							\
+		if (str[0] == '0') {					\
+			if (tolower(str[1]) == 'x' && isxdigit(str[2])) { \
+				base = 16; /* hex */			\
+				ptr += 2;				\
+			} else if (str[1] >= '0' && str[1] < 8) {	\
+				base = 8; /* octal */			\
+				ptr += 1;				\
+			} else {					\
+				return (EINVAL);			\
+			}						\
+		} else {						\
+			base = 10; /* decimal */			\
+		}							\
+	}								\
+									\
+	while (1) {							\
+		if (isdigit(*ptr))					\
+			digit = *ptr - '0';				\
+		else if (isalpha(*ptr))					\
+			digit = tolower(*ptr) - 'a' + 10;		\
+		else							\
+			break;						\
+									\
+		if (digit >= base)					\
+			break;						\
+									\
+		last_value = value;					\
+		value = value * base + digit;				\
+		if (last_value > value) /* Overflow */			\
+			return (ERANGE);				\
+									\
+		flag = 1;						\
+		ptr++;							\
+	}								\
+									\
+	if (flag)							\
+		*result = value;					\
+									\
+	if (endptr)							\
+		*endptr = (char *)(flag ? ptr : str);			\
+									\
+	return (0);							\
+}									\
+
+#define	define_ddi_strtox(type, valtype)				\
+int ddi_strto##type(const char *str, char **endptr,			\
+    int base, valtype *result)						\
+{									\
+	int rc;								\
+									\
+	if (*str == '-') {						\
+		rc = ddi_strtou##type(str + 1, endptr, base, result);	\
+		if (!rc) {						\
+			if (*endptr == str + 1)				\
+				*endptr = (char *)str;			\
+			else						\
+				*result = -*result;			\
+		}							\
+	} else {							\
+		rc = ddi_strtou##type(str, endptr, base, result);	\
+	}								\
+									\
+	return (rc);							\
+}
+
+define_ddi_strtoux(l, unsigned long)
+define_ddi_strtox(l, long)
+define_ddi_strtoux(ll, unsigned long long)
+define_ddi_strtox(ll, long long)
+
+EXPORT_SYMBOL(ddi_strtoul);
+EXPORT_SYMBOL(ddi_strtol);
+EXPORT_SYMBOL(ddi_strtoll);
+EXPORT_SYMBOL(ddi_strtoull);
+
+int
+ddi_copyin(const void *from, void *to, size_t len, int flags)
+{
+	/* Fake ioctl() issued by kernel, 'from' is a kernel address */
+	if (flags & FKIOCTL) {
+		memcpy(to, from, len);
+		return (0);
+	}
+
+	return (copyin(from, to, len));
+}
+EXPORT_SYMBOL(ddi_copyin);
+
+int
+ddi_copyout(const void *from, void *to, size_t len, int flags)
+{
+	/* Fake ioctl() issued by kernel, 'from' is a kernel address */
+	if (flags & FKIOCTL) {
+		memcpy(to, from, len);
+		return (0);
+	}
+
+	return (copyout(from, to, len));
+}
+EXPORT_SYMBOL(ddi_copyout);
+
+/*
+ * Read the unique system identifier from the /etc/hostid file.
+ *
+ * The behavior of /usr/bin/hostid on Linux systems with the
+ * regular eglibc and coreutils is:
+ *
+ *   1. Generate the value if the /etc/hostid file does not exist
+ *      or if the /etc/hostid file is less than four bytes in size.
+ *
+ *   2. If the /etc/hostid file is at least 4 bytes, then return
+ *      the first four bytes [0..3] in native endian order.
+ *
+ *   3. Always ignore bytes [4..] if they exist in the file.
+ *
+ * Only the first four bytes are significant, even on systems that
+ * have a 64-bit word size.
+ *
+ * See:
+ *
+ *   eglibc: sysdeps/unix/sysv/linux/gethostid.c
+ *   coreutils: src/hostid.c
+ *
+ * Notes:
+ *
+ * The /etc/hostid file on Solaris is a text file that often reads:
+ *
+ *   # DO NOT EDIT
+ *   "0123456789"
+ *
+ * Directly copying this file to Linux results in a constant
+ * hostid of 4f442023 because the default comment constitutes
+ * the first four bytes of the file.
+ *
+ */
+
+char *spl_hostid_path = HW_HOSTID_PATH;
+module_param(spl_hostid_path, charp, 0444);
+MODULE_PARM_DESC(spl_hostid_path, "The system hostid file (/etc/hostid)");
+
+static int
+hostid_read(uint32_t *hostid)
+{
+	uint64_t size;
+	struct _buf *file;
+	uint32_t value = 0;
+	int error;
+
+	file = kobj_open_file(spl_hostid_path);
+	if (file == (struct _buf *)-1)
+		return (ENOENT);
+
+	error = kobj_get_filesize(file, &size);
+	if (error) {
+		kobj_close_file(file);
+		return (error);
+	}
+
+	if (size < sizeof (HW_HOSTID_MASK)) {
+		kobj_close_file(file);
+		return (EINVAL);
+	}
+
+	/*
+	 * Read directly into the variable like eglibc does.
+	 * Short reads are okay; native behavior is preserved.
+	 */
+	error = kobj_read_file(file, (char *)&value, sizeof (value), 0);
+	if (error < 0) {
+		kobj_close_file(file);
+		return (EIO);
+	}
+
+	/* Mask down to 32 bits like coreutils does. */
+	*hostid = (value & HW_HOSTID_MASK);
+	kobj_close_file(file);
+
+	return (0);
+}
+
+/*
+ * Return the system hostid.  Preferentially use the spl_hostid module option
+ * when set, otherwise use the value in the /etc/hostid file.
+ */
+uint32_t
+zone_get_hostid(void *zone)
+{
+	uint32_t hostid;
+
+	ASSERT3P(zone, ==, NULL);
+
+	if (spl_hostid != 0)
+		return ((uint32_t)(spl_hostid & HW_HOSTID_MASK));
+
+	if (hostid_read(&hostid) == 0)
+		return (hostid);
+
+	return (0);
+}
+EXPORT_SYMBOL(zone_get_hostid);
+
+static int
+spl_kvmem_init(void)
+{
+	int rc = 0;
+
+	rc = spl_kmem_init();
+	if (rc)
+		return (rc);
+
+	rc = spl_vmem_init();
+	if (rc) {
+		spl_kmem_fini();
+		return (rc);
+	}
+
+	return (rc);
+}
+
+/*
+ * We initialize the random number generator with 128 bits of entropy from the
+ * system random number generator. In the improbable case that we have a zero
+ * seed, we fallback to the system jiffies, unless it is also zero, in which
+ * situation we use a preprogrammed seed. We step forward by 2^64 iterations to
+ * initialize each of the per-cpu seeds so that the sequences generated on each
+ * CPU are guaranteed to never overlap in practice.
+ */
+static void __init
+spl_random_init(void)
+{
+	uint64_t s[2];
+	int i;
+
+	get_random_bytes(s, sizeof (s));
+
+	if (s[0] == 0 && s[1] == 0) {
+		if (jiffies != 0) {
+			s[0] = jiffies;
+			s[1] = ~0 - jiffies;
+		} else {
+			(void) memcpy(s, "improbable seed", sizeof (s));
+		}
+		printk("SPL: get_random_bytes() returned 0 "
+		    "when generating random seed. Setting initial seed to "
+		    "0x%016llx%016llx.", cpu_to_be64(s[0]), cpu_to_be64(s[1]));
+	}
+
+	for_each_possible_cpu(i) {
+		uint64_t *wordp = per_cpu(spl_pseudo_entropy, i);
+
+		spl_rand_jump(s);
+
+		wordp[0] = s[0];
+		wordp[1] = s[1];
+	}
+}
+
+static void
+spl_kvmem_fini(void)
+{
+	spl_vmem_fini();
+	spl_kmem_fini();
+}
+
+static int __init
+spl_init(void)
+{
+	int rc = 0;
+
+	bzero(&p0, sizeof (proc_t));
+	spl_random_init();
+
+	if ((rc = spl_kvmem_init()))
+		goto out1;
+
+	if ((rc = spl_mutex_init()))
+		goto out2;
+
+	if ((rc = spl_rw_init()))
+		goto out3;
+
+	if ((rc = spl_tsd_init()))
+		goto out4;
+
+	if ((rc = spl_taskq_init()))
+		goto out5;
+
+	if ((rc = spl_kmem_cache_init()))
+		goto out6;
+
+	if ((rc = spl_vn_init()))
+		goto out7;
+
+	if ((rc = spl_proc_init()))
+		goto out8;
+
+	if ((rc = spl_kstat_init()))
+		goto out9;
+
+	if ((rc = spl_zlib_init()))
+		goto out10;
+
+	printk(KERN_NOTICE "SPL: Loaded module v%s-%s%s\n", SPL_META_VERSION,
+	    SPL_META_RELEASE, SPL_DEBUG_STR);
+	return (rc);
+
+out10:
+	spl_kstat_fini();
+out9:
+	spl_proc_fini();
+out8:
+	spl_vn_fini();
+out7:
+	spl_kmem_cache_fini();
+out6:
+	spl_taskq_fini();
+out5:
+	spl_tsd_fini();
+out4:
+	spl_rw_fini();
+out3:
+	spl_mutex_fini();
+out2:
+	spl_kvmem_fini();
+out1:
+	printk(KERN_NOTICE "SPL: Failed to Load Solaris Porting Layer "
+	    "v%s-%s%s, rc = %d\n", SPL_META_VERSION, SPL_META_RELEASE,
+	    SPL_DEBUG_STR, rc);
+
+	return (rc);
+}
+
+static void __exit
+spl_fini(void)
+{
+	printk(KERN_NOTICE "SPL: Unloaded module v%s-%s%s\n",
+	    SPL_META_VERSION, SPL_META_RELEASE, SPL_DEBUG_STR);
+	spl_zlib_fini();
+	spl_kstat_fini();
+	spl_proc_fini();
+	spl_vn_fini();
+	spl_kmem_cache_fini();
+	spl_taskq_fini();
+	spl_tsd_fini();
+	spl_rw_fini();
+	spl_mutex_fini();
+	spl_kvmem_fini();
+}
+
+module_init(spl_init);
+module_exit(spl_fini);
+
+MODULE_DESCRIPTION("Solaris Porting Layer");
+MODULE_AUTHOR(SPL_META_AUTHOR);
+MODULE_LICENSE(SPL_META_LICENSE);
+MODULE_VERSION(SPL_META_VERSION "-" SPL_META_RELEASE);
diff --git a/module/spl/spl-kmem-cache.c b/module/spl/spl-kmem-cache.c
new file mode 100644
index 000000000..5492c6a46
--- /dev/null
+++ b/module/spl/spl-kmem-cache.c
@@ -0,0 +1,1769 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/kmem.h>
+#include <sys/kmem_cache.h>
+#include <sys/shrinker.h>
+#include <sys/taskq.h>
+#include <sys/timer.h>
+#include <sys/vmem.h>
+#include <sys/wait.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/prefetch.h>
+
+/*
+ * Within the scope of spl-kmem.c file the kmem_cache_* definitions
+ * are removed to allow access to the real Linux slab allocator.
+ */
+#undef kmem_cache_destroy
+#undef kmem_cache_create
+#undef kmem_cache_alloc
+#undef kmem_cache_free
+
+
+/*
+ * Linux 3.16 replaced smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}()
+ * with smp_mb__{before,after}_atomic() because they were redundant. This is
+ * only used inside our SLAB allocator, so we implement an internal wrapper
+ * here to give us smp_mb__{before,after}_atomic() on older kernels.
+ */
+#ifndef smp_mb__before_atomic
+#define	smp_mb__before_atomic(x) smp_mb__before_clear_bit(x)
+#endif
+
+#ifndef smp_mb__after_atomic
+#define	smp_mb__after_atomic(x) smp_mb__after_clear_bit(x)
+#endif
+
+/*
+ * Cache expiration was implemented because it was part of the default Solaris
+ * kmem_cache behavior.  The idea is that per-cpu objects which haven't been
+ * accessed in several seconds should be returned to the cache.  On the other
+ * hand Linux slabs never move objects back to the slabs unless there is
+ * memory pressure on the system.  By default the Linux method is enabled
+ * because it has been shown to improve responsiveness on low memory systems.
+ * This policy may be changed by setting KMC_EXPIRE_AGE or KMC_EXPIRE_MEM.
+ */
+/* BEGIN CSTYLED */
+unsigned int spl_kmem_cache_expire = KMC_EXPIRE_MEM;
+EXPORT_SYMBOL(spl_kmem_cache_expire);
+module_param(spl_kmem_cache_expire, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_expire, "By age (0x1) or low memory (0x2)");
+
+/*
+ * Cache magazines are an optimization designed to minimize the cost of
+ * allocating memory.  They do this by keeping a per-cpu cache of recently
+ * freed objects, which can then be reallocated without taking a lock. This
+ * can improve performance on highly contended caches.  However, because
+ * objects in magazines will prevent otherwise empty slabs from being
+ * immediately released this may not be ideal for low memory machines.
+ *
+ * For this reason spl_kmem_cache_magazine_size can be used to set a maximum
+ * magazine size.  When this value is set to 0 the magazine size will be
+ * automatically determined based on the object size.  Otherwise magazines
+ * will be limited to 2-256 objects per magazine (i.e per cpu).  Magazines
+ * may never be entirely disabled in this implementation.
+ */
+unsigned int spl_kmem_cache_magazine_size = 0;
+module_param(spl_kmem_cache_magazine_size, uint, 0444);
+MODULE_PARM_DESC(spl_kmem_cache_magazine_size,
+	"Default magazine size (2-256), set automatically (0)");
+
+/*
+ * The default behavior is to report the number of objects remaining in the
+ * cache.  This allows the Linux VM to repeatedly reclaim objects from the
+ * cache when memory is low satisfy other memory allocations.  Alternately,
+ * setting this value to KMC_RECLAIM_ONCE limits how aggressively the cache
+ * is reclaimed.  This may increase the likelihood of out of memory events.
+ */
+unsigned int spl_kmem_cache_reclaim = 0 /* KMC_RECLAIM_ONCE */;
+module_param(spl_kmem_cache_reclaim, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_reclaim, "Single reclaim pass (0x1)");
+
+unsigned int spl_kmem_cache_obj_per_slab = SPL_KMEM_CACHE_OBJ_PER_SLAB;
+module_param(spl_kmem_cache_obj_per_slab, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_obj_per_slab, "Number of objects per slab");
+
+unsigned int spl_kmem_cache_obj_per_slab_min = SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN;
+module_param(spl_kmem_cache_obj_per_slab_min, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_obj_per_slab_min,
+	"Minimal number of objects per slab");
+
+unsigned int spl_kmem_cache_max_size = SPL_KMEM_CACHE_MAX_SIZE;
+module_param(spl_kmem_cache_max_size, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_max_size, "Maximum size of slab in MB");
+
+/*
+ * For small objects the Linux slab allocator should be used to make the most
+ * efficient use of the memory.  However, large objects are not supported by
+ * the Linux slab and therefore the SPL implementation is preferred.  A cutoff
+ * of 16K was determined to be optimal for architectures using 4K pages.
+ */
+#if PAGE_SIZE == 4096
+unsigned int spl_kmem_cache_slab_limit = 16384;
+#else
+unsigned int spl_kmem_cache_slab_limit = 0;
+#endif
+module_param(spl_kmem_cache_slab_limit, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_slab_limit,
+	"Objects less than N bytes use the Linux slab");
+
+/*
+ * This value defaults to a threshold designed to avoid allocations which
+ * have been deemed costly by the kernel.
+ */
+unsigned int spl_kmem_cache_kmem_limit =
+	((1 << (PAGE_ALLOC_COSTLY_ORDER - 1)) * PAGE_SIZE) /
+	SPL_KMEM_CACHE_OBJ_PER_SLAB;
+module_param(spl_kmem_cache_kmem_limit, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_cache_kmem_limit,
+	"Objects less than N bytes use the kmalloc");
+
+/*
+ * The number of threads available to allocate new slabs for caches.  This
+ * should not need to be tuned but it is available for performance analysis.
+ */
+unsigned int spl_kmem_cache_kmem_threads = 4;
+module_param(spl_kmem_cache_kmem_threads, uint, 0444);
+MODULE_PARM_DESC(spl_kmem_cache_kmem_threads,
+	"Number of spl_kmem_cache threads");
+/* END CSTYLED */
+
+/*
+ * Slab allocation interfaces
+ *
+ * While the Linux slab implementation was inspired by the Solaris
+ * implementation I cannot use it to emulate the Solaris APIs.  I
+ * require two features which are not provided by the Linux slab.
+ *
+ * 1) Constructors AND destructors.  Recent versions of the Linux
+ *    kernel have removed support for destructors.  This is a deal
+ *    breaker for the SPL which contains particularly expensive
+ *    initializers for mutex's, condition variables, etc.  We also
+ *    require a minimal level of cleanup for these data types unlike
+ *    many Linux data types which do need to be explicitly destroyed.
+ *
+ * 2) Virtual address space backed slab.  Callers of the Solaris slab
+ *    expect it to work well for both small are very large allocations.
+ *    Because of memory fragmentation the Linux slab which is backed
+ *    by kmalloc'ed memory performs very badly when confronted with
+ *    large numbers of large allocations.  Basing the slab on the
+ *    virtual address space removes the need for contiguous pages
+ *    and greatly improve performance for large allocations.
+ *
+ * For these reasons, the SPL has its own slab implementation with
+ * the needed features.  It is not as highly optimized as either the
+ * Solaris or Linux slabs, but it should get me most of what is
+ * needed until it can be optimized or obsoleted by another approach.
+ *
+ * One serious concern I do have about this method is the relatively
+ * small virtual address space on 32bit arches.  This will seriously
+ * constrain the size of the slab caches and their performance.
+ */
+
+struct list_head spl_kmem_cache_list;   /* List of caches */
+struct rw_semaphore spl_kmem_cache_sem; /* Cache list lock */
+taskq_t *spl_kmem_cache_taskq;		/* Task queue for ageing / reclaim */
+
+static void spl_cache_shrink(spl_kmem_cache_t *skc, void *obj);
+
+SPL_SHRINKER_CALLBACK_FWD_DECLARE(spl_kmem_cache_generic_shrinker);
+SPL_SHRINKER_DECLARE(spl_kmem_cache_shrinker,
+	spl_kmem_cache_generic_shrinker, KMC_DEFAULT_SEEKS);
+
+static void *
+kv_alloc(spl_kmem_cache_t *skc, int size, int flags)
+{
+	gfp_t lflags = kmem_flags_convert(flags);
+	void *ptr;
+
+	if (skc->skc_flags & KMC_KMEM) {
+		ASSERT(ISP2(size));
+		ptr = (void *)__get_free_pages(lflags, get_order(size));
+	} else {
+		ptr = __vmalloc(size, lflags | __GFP_HIGHMEM, PAGE_KERNEL);
+	}
+
+	/* Resulting allocated memory will be page aligned */
+	ASSERT(IS_P2ALIGNED(ptr, PAGE_SIZE));
+
+	return (ptr);
+}
+
+static void
+kv_free(spl_kmem_cache_t *skc, void *ptr, int size)
+{
+	ASSERT(IS_P2ALIGNED(ptr, PAGE_SIZE));
+
+	/*
+	 * The Linux direct reclaim path uses this out of band value to
+	 * determine if forward progress is being made.  Normally this is
+	 * incremented by kmem_freepages() which is part of the various
+	 * Linux slab implementations.  However, since we are using none
+	 * of that infrastructure we are responsible for incrementing it.
+	 */
+	if (current->reclaim_state)
+		current->reclaim_state->reclaimed_slab += size >> PAGE_SHIFT;
+
+	if (skc->skc_flags & KMC_KMEM) {
+		ASSERT(ISP2(size));
+		free_pages((unsigned long)ptr, get_order(size));
+	} else {
+		vfree(ptr);
+	}
+}
+
+/*
+ * Required space for each aligned sks.
+ */
+static inline uint32_t
+spl_sks_size(spl_kmem_cache_t *skc)
+{
+	return (P2ROUNDUP_TYPED(sizeof (spl_kmem_slab_t),
+	    skc->skc_obj_align, uint32_t));
+}
+
+/*
+ * Required space for each aligned object.
+ */
+static inline uint32_t
+spl_obj_size(spl_kmem_cache_t *skc)
+{
+	uint32_t align = skc->skc_obj_align;
+
+	return (P2ROUNDUP_TYPED(skc->skc_obj_size, align, uint32_t) +
+	    P2ROUNDUP_TYPED(sizeof (spl_kmem_obj_t), align, uint32_t));
+}
+
+/*
+ * Lookup the spl_kmem_object_t for an object given that object.
+ */
+static inline spl_kmem_obj_t *
+spl_sko_from_obj(spl_kmem_cache_t *skc, void *obj)
+{
+	return (obj + P2ROUNDUP_TYPED(skc->skc_obj_size,
+	    skc->skc_obj_align, uint32_t));
+}
+
+/*
+ * Required space for each offslab object taking in to account alignment
+ * restrictions and the power-of-two requirement of kv_alloc().
+ */
+static inline uint32_t
+spl_offslab_size(spl_kmem_cache_t *skc)
+{
+	return (1UL << (fls64(spl_obj_size(skc)) + 1));
+}
+
+/*
+ * It's important that we pack the spl_kmem_obj_t structure and the
+ * actual objects in to one large address space to minimize the number
+ * of calls to the allocator.  It is far better to do a few large
+ * allocations and then subdivide it ourselves.  Now which allocator
+ * we use requires balancing a few trade offs.
+ *
+ * For small objects we use kmem_alloc() because as long as you are
+ * only requesting a small number of pages (ideally just one) its cheap.
+ * However, when you start requesting multiple pages with kmem_alloc()
+ * it gets increasingly expensive since it requires contiguous pages.
+ * For this reason we shift to vmem_alloc() for slabs of large objects
+ * which removes the need for contiguous pages.  We do not use
+ * vmem_alloc() in all cases because there is significant locking
+ * overhead in __get_vm_area_node().  This function takes a single
+ * global lock when acquiring an available virtual address range which
+ * serializes all vmem_alloc()'s for all slab caches.  Using slightly
+ * different allocation functions for small and large objects should
+ * give us the best of both worlds.
+ *
+ * KMC_ONSLAB                       KMC_OFFSLAB
+ *
+ * +------------------------+       +-----------------+
+ * | spl_kmem_slab_t --+-+  |       | spl_kmem_slab_t |---+-+
+ * | skc_obj_size    <-+ |  |       +-----------------+   | |
+ * | spl_kmem_obj_t      |  |                             | |
+ * | skc_obj_size    <---+  |       +-----------------+   | |
+ * | spl_kmem_obj_t      |  |       | skc_obj_size    | <-+ |
+ * | ...                 v  |       | spl_kmem_obj_t  |     |
+ * +------------------------+       +-----------------+     v
+ */
+static spl_kmem_slab_t *
+spl_slab_alloc(spl_kmem_cache_t *skc, int flags)
+{
+	spl_kmem_slab_t *sks;
+	spl_kmem_obj_t *sko, *n;
+	void *base, *obj;
+	uint32_t obj_size, offslab_size = 0;
+	int i,  rc = 0;
+
+	base = kv_alloc(skc, skc->skc_slab_size, flags);
+	if (base == NULL)
+		return (NULL);
+
+	sks = (spl_kmem_slab_t *)base;
+	sks->sks_magic = SKS_MAGIC;
+	sks->sks_objs = skc->skc_slab_objs;
+	sks->sks_age = jiffies;
+	sks->sks_cache = skc;
+	INIT_LIST_HEAD(&sks->sks_list);
+	INIT_LIST_HEAD(&sks->sks_free_list);
+	sks->sks_ref = 0;
+	obj_size = spl_obj_size(skc);
+
+	if (skc->skc_flags & KMC_OFFSLAB)
+		offslab_size = spl_offslab_size(skc);
+
+	for (i = 0; i < sks->sks_objs; i++) {
+		if (skc->skc_flags & KMC_OFFSLAB) {
+			obj = kv_alloc(skc, offslab_size, flags);
+			if (!obj) {
+				rc = -ENOMEM;
+				goto out;
+			}
+		} else {
+			obj = base + spl_sks_size(skc) + (i * obj_size);
+		}
+
+		ASSERT(IS_P2ALIGNED(obj, skc->skc_obj_align));
+		sko = spl_sko_from_obj(skc, obj);
+		sko->sko_addr = obj;
+		sko->sko_magic = SKO_MAGIC;
+		sko->sko_slab = sks;
+		INIT_LIST_HEAD(&sko->sko_list);
+		list_add_tail(&sko->sko_list, &sks->sks_free_list);
+	}
+
+out:
+	if (rc) {
+		if (skc->skc_flags & KMC_OFFSLAB)
+			list_for_each_entry_safe(sko,
+			    n, &sks->sks_free_list, sko_list) {
+				kv_free(skc, sko->sko_addr, offslab_size);
+			}
+
+		kv_free(skc, base, skc->skc_slab_size);
+		sks = NULL;
+	}
+
+	return (sks);
+}
+
+/*
+ * Remove a slab from complete or partial list, it must be called with
+ * the 'skc->skc_lock' held but the actual free must be performed
+ * outside the lock to prevent deadlocking on vmem addresses.
+ */
+static void
+spl_slab_free(spl_kmem_slab_t *sks,
+    struct list_head *sks_list, struct list_head *sko_list)
+{
+	spl_kmem_cache_t *skc;
+
+	ASSERT(sks->sks_magic == SKS_MAGIC);
+	ASSERT(sks->sks_ref == 0);
+
+	skc = sks->sks_cache;
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+
+	/*
+	 * Update slab/objects counters in the cache, then remove the
+	 * slab from the skc->skc_partial_list.  Finally add the slab
+	 * and all its objects in to the private work lists where the
+	 * destructors will be called and the memory freed to the system.
+	 */
+	skc->skc_obj_total -= sks->sks_objs;
+	skc->skc_slab_total--;
+	list_del(&sks->sks_list);
+	list_add(&sks->sks_list, sks_list);
+	list_splice_init(&sks->sks_free_list, sko_list);
+}
+
+/*
+ * Reclaim empty slabs at the end of the partial list.
+ */
+static void
+spl_slab_reclaim(spl_kmem_cache_t *skc)
+{
+	spl_kmem_slab_t *sks, *m;
+	spl_kmem_obj_t *sko, *n;
+	LIST_HEAD(sks_list);
+	LIST_HEAD(sko_list);
+	uint32_t size = 0;
+
+	/*
+	 * Empty slabs and objects must be moved to a private list so they
+	 * can be safely freed outside the spin lock.  All empty slabs are
+	 * at the end of skc->skc_partial_list, therefore once a non-empty
+	 * slab is found we can stop scanning.
+	 */
+	spin_lock(&skc->skc_lock);
+	list_for_each_entry_safe_reverse(sks, m,
+	    &skc->skc_partial_list, sks_list) {
+
+		if (sks->sks_ref > 0)
+			break;
+
+		spl_slab_free(sks, &sks_list, &sko_list);
+	}
+	spin_unlock(&skc->skc_lock);
+
+	/*
+	 * The following two loops ensure all the object destructors are
+	 * run, any offslab objects are freed, and the slabs themselves
+	 * are freed.  This is all done outside the skc->skc_lock since
+	 * this allows the destructor to sleep, and allows us to perform
+	 * a conditional reschedule when a freeing a large number of
+	 * objects and slabs back to the system.
+	 */
+	if (skc->skc_flags & KMC_OFFSLAB)
+		size = spl_offslab_size(skc);
+
+	list_for_each_entry_safe(sko, n, &sko_list, sko_list) {
+		ASSERT(sko->sko_magic == SKO_MAGIC);
+
+		if (skc->skc_flags & KMC_OFFSLAB)
+			kv_free(skc, sko->sko_addr, size);
+	}
+
+	list_for_each_entry_safe(sks, m, &sks_list, sks_list) {
+		ASSERT(sks->sks_magic == SKS_MAGIC);
+		kv_free(skc, sks, skc->skc_slab_size);
+	}
+}
+
+static spl_kmem_emergency_t *
+spl_emergency_search(struct rb_root *root, void *obj)
+{
+	struct rb_node *node = root->rb_node;
+	spl_kmem_emergency_t *ske;
+	unsigned long address = (unsigned long)obj;
+
+	while (node) {
+		ske = container_of(node, spl_kmem_emergency_t, ske_node);
+
+		if (address < ske->ske_obj)
+			node = node->rb_left;
+		else if (address > ske->ske_obj)
+			node = node->rb_right;
+		else
+			return (ske);
+	}
+
+	return (NULL);
+}
+
+static int
+spl_emergency_insert(struct rb_root *root, spl_kmem_emergency_t *ske)
+{
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+	spl_kmem_emergency_t *ske_tmp;
+	unsigned long address = ske->ske_obj;
+
+	while (*new) {
+		ske_tmp = container_of(*new, spl_kmem_emergency_t, ske_node);
+
+		parent = *new;
+		if (address < ske_tmp->ske_obj)
+			new = &((*new)->rb_left);
+		else if (address > ske_tmp->ske_obj)
+			new = &((*new)->rb_right);
+		else
+			return (0);
+	}
+
+	rb_link_node(&ske->ske_node, parent, new);
+	rb_insert_color(&ske->ske_node, root);
+
+	return (1);
+}
+
+/*
+ * Allocate a single emergency object and track it in a red black tree.
+ */
+static int
+spl_emergency_alloc(spl_kmem_cache_t *skc, int flags, void **obj)
+{
+	gfp_t lflags = kmem_flags_convert(flags);
+	spl_kmem_emergency_t *ske;
+	int order = get_order(skc->skc_obj_size);
+	int empty;
+
+	/* Last chance use a partial slab if one now exists */
+	spin_lock(&skc->skc_lock);
+	empty = list_empty(&skc->skc_partial_list);
+	spin_unlock(&skc->skc_lock);
+	if (!empty)
+		return (-EEXIST);
+
+	ske = kmalloc(sizeof (*ske), lflags);
+	if (ske == NULL)
+		return (-ENOMEM);
+
+	ske->ske_obj = __get_free_pages(lflags, order);
+	if (ske->ske_obj == 0) {
+		kfree(ske);
+		return (-ENOMEM);
+	}
+
+	spin_lock(&skc->skc_lock);
+	empty = spl_emergency_insert(&skc->skc_emergency_tree, ske);
+	if (likely(empty)) {
+		skc->skc_obj_total++;
+		skc->skc_obj_emergency++;
+		if (skc->skc_obj_emergency > skc->skc_obj_emergency_max)
+			skc->skc_obj_emergency_max = skc->skc_obj_emergency;
+	}
+	spin_unlock(&skc->skc_lock);
+
+	if (unlikely(!empty)) {
+		free_pages(ske->ske_obj, order);
+		kfree(ske);
+		return (-EINVAL);
+	}
+
+	*obj = (void *)ske->ske_obj;
+
+	return (0);
+}
+
+/*
+ * Locate the passed object in the red black tree and free it.
+ */
+static int
+spl_emergency_free(spl_kmem_cache_t *skc, void *obj)
+{
+	spl_kmem_emergency_t *ske;
+	int order = get_order(skc->skc_obj_size);
+
+	spin_lock(&skc->skc_lock);
+	ske = spl_emergency_search(&skc->skc_emergency_tree, obj);
+	if (ske) {
+		rb_erase(&ske->ske_node, &skc->skc_emergency_tree);
+		skc->skc_obj_emergency--;
+		skc->skc_obj_total--;
+	}
+	spin_unlock(&skc->skc_lock);
+
+	if (ske == NULL)
+		return (-ENOENT);
+
+	free_pages(ske->ske_obj, order);
+	kfree(ske);
+
+	return (0);
+}
+
+/*
+ * Release objects from the per-cpu magazine back to their slab.  The flush
+ * argument contains the max number of entries to remove from the magazine.
+ */
+static void
+__spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
+{
+	int i, count = MIN(flush, skm->skm_avail);
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+
+	for (i = 0; i < count; i++)
+		spl_cache_shrink(skc, skm->skm_objs[i]);
+
+	skm->skm_avail -= count;
+	memmove(skm->skm_objs, &(skm->skm_objs[count]),
+	    sizeof (void *) * skm->skm_avail);
+}
+
+static void
+spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
+{
+	spin_lock(&skc->skc_lock);
+	__spl_cache_flush(skc, skm, flush);
+	spin_unlock(&skc->skc_lock);
+}
+
+static void
+spl_magazine_age(void *data)
+{
+	spl_kmem_cache_t *skc = (spl_kmem_cache_t *)data;
+	spl_kmem_magazine_t *skm = skc->skc_mag[smp_processor_id()];
+
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+	ASSERT(skm->skm_cpu == smp_processor_id());
+	ASSERT(irqs_disabled());
+
+	/* There are no available objects or they are too young to age out */
+	if ((skm->skm_avail == 0) ||
+	    time_before(jiffies, skm->skm_age + skc->skc_delay * HZ))
+		return;
+
+	/*
+	 * Because we're executing in interrupt context we may have
+	 * interrupted the holder of this lock.  To avoid a potential
+	 * deadlock return if the lock is contended.
+	 */
+	if (!spin_trylock(&skc->skc_lock))
+		return;
+
+	__spl_cache_flush(skc, skm, skm->skm_refill);
+	spin_unlock(&skc->skc_lock);
+}
+
+/*
+ * Called regularly to keep a downward pressure on the cache.
+ *
+ * Objects older than skc->skc_delay seconds in the per-cpu magazines will
+ * be returned to the caches.  This is done to prevent idle magazines from
+ * holding memory which could be better used elsewhere.  The delay is
+ * present to prevent thrashing the magazine.
+ *
+ * The newly released objects may result in empty partial slabs.  Those
+ * slabs should be released to the system.  Otherwise moving the objects
+ * out of the magazines is just wasted work.
+ */
+static void
+spl_cache_age(void *data)
+{
+	spl_kmem_cache_t *skc = (spl_kmem_cache_t *)data;
+	taskqid_t id = 0;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+
+	/* Dynamically disabled at run time */
+	if (!(spl_kmem_cache_expire & KMC_EXPIRE_AGE))
+		return;
+
+	atomic_inc(&skc->skc_ref);
+
+	if (!(skc->skc_flags & KMC_NOMAGAZINE))
+		on_each_cpu(spl_magazine_age, skc, 1);
+
+	spl_slab_reclaim(skc);
+
+	while (!test_bit(KMC_BIT_DESTROY, &skc->skc_flags) && !id) {
+		id = taskq_dispatch_delay(
+		    spl_kmem_cache_taskq, spl_cache_age, skc, TQ_SLEEP,
+		    ddi_get_lbolt() + skc->skc_delay / 3 * HZ);
+
+		/* Destroy issued after dispatch immediately cancel it */
+		if (test_bit(KMC_BIT_DESTROY, &skc->skc_flags) && id)
+			taskq_cancel_id(spl_kmem_cache_taskq, id);
+	}
+
+	spin_lock(&skc->skc_lock);
+	skc->skc_taskqid = id;
+	spin_unlock(&skc->skc_lock);
+
+	atomic_dec(&skc->skc_ref);
+}
+
+/*
+ * Size a slab based on the size of each aligned object plus spl_kmem_obj_t.
+ * When on-slab we want to target spl_kmem_cache_obj_per_slab.  However,
+ * for very small objects we may end up with more than this so as not
+ * to waste space in the minimal allocation of a single page.  Also for
+ * very large objects we may use as few as spl_kmem_cache_obj_per_slab_min,
+ * lower than this and we will fail.
+ */
+static int
+spl_slab_size(spl_kmem_cache_t *skc, uint32_t *objs, uint32_t *size)
+{
+	uint32_t sks_size, obj_size, max_size, tgt_size, tgt_objs;
+
+	if (skc->skc_flags & KMC_OFFSLAB) {
+		tgt_objs = spl_kmem_cache_obj_per_slab;
+		tgt_size = P2ROUNDUP(sizeof (spl_kmem_slab_t), PAGE_SIZE);
+
+		if ((skc->skc_flags & KMC_KMEM) &&
+		    (spl_obj_size(skc) > (SPL_MAX_ORDER_NR_PAGES * PAGE_SIZE)))
+			return (-ENOSPC);
+	} else {
+		sks_size = spl_sks_size(skc);
+		obj_size = spl_obj_size(skc);
+		max_size = (spl_kmem_cache_max_size * 1024 * 1024);
+		tgt_size = (spl_kmem_cache_obj_per_slab * obj_size + sks_size);
+
+		/*
+		 * KMC_KMEM slabs are allocated by __get_free_pages() which
+		 * rounds up to the nearest order.  Knowing this the size
+		 * should be rounded up to the next power of two with a hard
+		 * maximum defined by the maximum allowed allocation order.
+		 */
+		if (skc->skc_flags & KMC_KMEM) {
+			max_size = SPL_MAX_ORDER_NR_PAGES * PAGE_SIZE;
+			tgt_size = MIN(max_size,
+			    PAGE_SIZE * (1 << MAX(get_order(tgt_size) - 1, 1)));
+		}
+
+		if (tgt_size <= max_size) {
+			tgt_objs = (tgt_size - sks_size) / obj_size;
+		} else {
+			tgt_objs = (max_size - sks_size) / obj_size;
+			tgt_size = (tgt_objs * obj_size) + sks_size;
+		}
+	}
+
+	if (tgt_objs == 0)
+		return (-ENOSPC);
+
+	*objs = tgt_objs;
+	*size = tgt_size;
+
+	return (0);
+}
+
+/*
+ * Make a guess at reasonable per-cpu magazine size based on the size of
+ * each object and the cost of caching N of them in each magazine.  Long
+ * term this should really adapt based on an observed usage heuristic.
+ */
+static int
+spl_magazine_size(spl_kmem_cache_t *skc)
+{
+	uint32_t obj_size = spl_obj_size(skc);
+	int size;
+
+	if (spl_kmem_cache_magazine_size > 0)
+		return (MAX(MIN(spl_kmem_cache_magazine_size, 256), 2));
+
+	/* Per-magazine sizes below assume a 4Kib page size */
+	if (obj_size > (PAGE_SIZE * 256))
+		size = 4;  /* Minimum 4Mib per-magazine */
+	else if (obj_size > (PAGE_SIZE * 32))
+		size = 16; /* Minimum 2Mib per-magazine */
+	else if (obj_size > (PAGE_SIZE))
+		size = 64; /* Minimum 256Kib per-magazine */
+	else if (obj_size > (PAGE_SIZE / 4))
+		size = 128; /* Minimum 128Kib per-magazine */
+	else
+		size = 256;
+
+	return (size);
+}
+
+/*
+ * Allocate a per-cpu magazine to associate with a specific core.
+ */
+static spl_kmem_magazine_t *
+spl_magazine_alloc(spl_kmem_cache_t *skc, int cpu)
+{
+	spl_kmem_magazine_t *skm;
+	int size = sizeof (spl_kmem_magazine_t) +
+	    sizeof (void *) * skc->skc_mag_size;
+
+	skm = kmalloc_node(size, GFP_KERNEL, cpu_to_node(cpu));
+	if (skm) {
+		skm->skm_magic = SKM_MAGIC;
+		skm->skm_avail = 0;
+		skm->skm_size = skc->skc_mag_size;
+		skm->skm_refill = skc->skc_mag_refill;
+		skm->skm_cache = skc;
+		skm->skm_age = jiffies;
+		skm->skm_cpu = cpu;
+	}
+
+	return (skm);
+}
+
+/*
+ * Free a per-cpu magazine associated with a specific core.
+ */
+static void
+spl_magazine_free(spl_kmem_magazine_t *skm)
+{
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+	ASSERT(skm->skm_avail == 0);
+	kfree(skm);
+}
+
+/*
+ * Create all pre-cpu magazines of reasonable sizes.
+ */
+static int
+spl_magazine_create(spl_kmem_cache_t *skc)
+{
+	int i;
+
+	if (skc->skc_flags & KMC_NOMAGAZINE)
+		return (0);
+
+	skc->skc_mag = kzalloc(sizeof (spl_kmem_magazine_t *) *
+	    num_possible_cpus(), kmem_flags_convert(KM_SLEEP));
+	skc->skc_mag_size = spl_magazine_size(skc);
+	skc->skc_mag_refill = (skc->skc_mag_size + 1) / 2;
+
+	for_each_possible_cpu(i) {
+		skc->skc_mag[i] = spl_magazine_alloc(skc, i);
+		if (!skc->skc_mag[i]) {
+			for (i--; i >= 0; i--)
+				spl_magazine_free(skc->skc_mag[i]);
+
+			kfree(skc->skc_mag);
+			return (-ENOMEM);
+		}
+	}
+
+	return (0);
+}
+
+/*
+ * Destroy all pre-cpu magazines.
+ */
+static void
+spl_magazine_destroy(spl_kmem_cache_t *skc)
+{
+	spl_kmem_magazine_t *skm;
+	int i;
+
+	if (skc->skc_flags & KMC_NOMAGAZINE)
+		return;
+
+	for_each_possible_cpu(i) {
+		skm = skc->skc_mag[i];
+		spl_cache_flush(skc, skm, skm->skm_avail);
+		spl_magazine_free(skm);
+	}
+
+	kfree(skc->skc_mag);
+}
+
+/*
+ * Create a object cache based on the following arguments:
+ * name		cache name
+ * size		cache object size
+ * align	cache object alignment
+ * ctor		cache object constructor
+ * dtor		cache object destructor
+ * reclaim	cache object reclaim
+ * priv		cache private data for ctor/dtor/reclaim
+ * vmp		unused must be NULL
+ * flags
+ *	KMC_NOTOUCH	Disable cache object aging (unsupported)
+ *	KMC_NODEBUG	Disable debugging (unsupported)
+ *	KMC_NOHASH      Disable hashing (unsupported)
+ *	KMC_QCACHE	Disable qcache (unsupported)
+ *	KMC_NOMAGAZINE	Enabled for kmem/vmem, Disabled for Linux slab
+ *	KMC_KMEM	Force kmem backed cache
+ *	KMC_VMEM        Force vmem backed cache
+ *	KMC_SLAB        Force Linux slab backed cache
+ *	KMC_OFFSLAB	Locate objects off the slab
+ */
+spl_kmem_cache_t *
+spl_kmem_cache_create(char *name, size_t size, size_t align,
+    spl_kmem_ctor_t ctor, spl_kmem_dtor_t dtor, spl_kmem_reclaim_t reclaim,
+    void *priv, void *vmp, int flags)
+{
+	gfp_t lflags = kmem_flags_convert(KM_SLEEP);
+	spl_kmem_cache_t *skc;
+	int rc;
+
+	/*
+	 * Unsupported flags
+	 */
+	ASSERT0(flags & KMC_NOMAGAZINE);
+	ASSERT0(flags & KMC_NOHASH);
+	ASSERT0(flags & KMC_QCACHE);
+	ASSERT(vmp == NULL);
+
+	might_sleep();
+
+	skc = kzalloc(sizeof (*skc), lflags);
+	if (skc == NULL)
+		return (NULL);
+
+	skc->skc_magic = SKC_MAGIC;
+	skc->skc_name_size = strlen(name) + 1;
+	skc->skc_name = (char *)kmalloc(skc->skc_name_size, lflags);
+	if (skc->skc_name == NULL) {
+		kfree(skc);
+		return (NULL);
+	}
+	strncpy(skc->skc_name, name, skc->skc_name_size);
+
+	skc->skc_ctor = ctor;
+	skc->skc_dtor = dtor;
+	skc->skc_reclaim = reclaim;
+	skc->skc_private = priv;
+	skc->skc_vmp = vmp;
+	skc->skc_linux_cache = NULL;
+	skc->skc_flags = flags;
+	skc->skc_obj_size = size;
+	skc->skc_obj_align = SPL_KMEM_CACHE_ALIGN;
+	skc->skc_delay = SPL_KMEM_CACHE_DELAY;
+	skc->skc_reap = SPL_KMEM_CACHE_REAP;
+	atomic_set(&skc->skc_ref, 0);
+
+	INIT_LIST_HEAD(&skc->skc_list);
+	INIT_LIST_HEAD(&skc->skc_complete_list);
+	INIT_LIST_HEAD(&skc->skc_partial_list);
+	skc->skc_emergency_tree = RB_ROOT;
+	spin_lock_init(&skc->skc_lock);
+	init_waitqueue_head(&skc->skc_waitq);
+	skc->skc_slab_fail = 0;
+	skc->skc_slab_create = 0;
+	skc->skc_slab_destroy = 0;
+	skc->skc_slab_total = 0;
+	skc->skc_slab_alloc = 0;
+	skc->skc_slab_max = 0;
+	skc->skc_obj_total = 0;
+	skc->skc_obj_alloc = 0;
+	skc->skc_obj_max = 0;
+	skc->skc_obj_deadlock = 0;
+	skc->skc_obj_emergency = 0;
+	skc->skc_obj_emergency_max = 0;
+
+	/*
+	 * Verify the requested alignment restriction is sane.
+	 */
+	if (align) {
+		VERIFY(ISP2(align));
+		VERIFY3U(align, >=, SPL_KMEM_CACHE_ALIGN);
+		VERIFY3U(align, <=, PAGE_SIZE);
+		skc->skc_obj_align = align;
+	}
+
+	/*
+	 * When no specific type of slab is requested (kmem, vmem, or
+	 * linuxslab) then select a cache type based on the object size
+	 * and default tunables.
+	 */
+	if (!(skc->skc_flags & (KMC_KMEM | KMC_VMEM | KMC_SLAB))) {
+
+		/*
+		 * Objects smaller than spl_kmem_cache_slab_limit can
+		 * use the Linux slab for better space-efficiency.  By
+		 * default this functionality is disabled until its
+		 * performance characteristics are fully understood.
+		 */
+		if (spl_kmem_cache_slab_limit &&
+		    size <= (size_t)spl_kmem_cache_slab_limit)
+			skc->skc_flags |= KMC_SLAB;
+
+		/*
+		 * Small objects, less than spl_kmem_cache_kmem_limit per
+		 * object should use kmem because their slabs are small.
+		 */
+		else if (spl_obj_size(skc) <= spl_kmem_cache_kmem_limit)
+			skc->skc_flags |= KMC_KMEM;
+
+		/*
+		 * All other objects are considered large and are placed
+		 * on vmem backed slabs.
+		 */
+		else
+			skc->skc_flags |= KMC_VMEM;
+	}
+
+	/*
+	 * Given the type of slab allocate the required resources.
+	 */
+	if (skc->skc_flags & (KMC_KMEM | KMC_VMEM)) {
+		rc = spl_slab_size(skc,
+		    &skc->skc_slab_objs, &skc->skc_slab_size);
+		if (rc)
+			goto out;
+
+		rc = spl_magazine_create(skc);
+		if (rc)
+			goto out;
+	} else {
+		unsigned long slabflags = 0;
+
+		if (size > (SPL_MAX_KMEM_ORDER_NR_PAGES * PAGE_SIZE)) {
+			rc = EINVAL;
+			goto out;
+		}
+
+#if defined(SLAB_USERCOPY)
+		/*
+		 * Required for PAX-enabled kernels if the slab is to be
+		 * used for coping between user and kernel space.
+		 */
+		slabflags |= SLAB_USERCOPY;
+#endif
+
+#if defined(HAVE_KMEM_CACHE_CREATE_USERCOPY)
+	/*
+	 * Newer grsec patchset uses kmem_cache_create_usercopy()
+	 * instead of SLAB_USERCOPY flag
+	 */
+	skc->skc_linux_cache = kmem_cache_create_usercopy(
+	    skc->skc_name, size, align, slabflags, 0, size, NULL);
+#else
+	skc->skc_linux_cache = kmem_cache_create(
+	    skc->skc_name, size, align, slabflags, NULL);
+#endif
+		if (skc->skc_linux_cache == NULL) {
+			rc = ENOMEM;
+			goto out;
+		}
+
+#if defined(HAVE_KMEM_CACHE_ALLOCFLAGS)
+		skc->skc_linux_cache->allocflags |= __GFP_COMP;
+#elif defined(HAVE_KMEM_CACHE_GFPFLAGS)
+		skc->skc_linux_cache->gfpflags |= __GFP_COMP;
+#endif
+		skc->skc_flags |= KMC_NOMAGAZINE;
+	}
+
+	if (spl_kmem_cache_expire & KMC_EXPIRE_AGE)
+		skc->skc_taskqid = taskq_dispatch_delay(spl_kmem_cache_taskq,
+		    spl_cache_age, skc, TQ_SLEEP,
+		    ddi_get_lbolt() + skc->skc_delay / 3 * HZ);
+
+	down_write(&spl_kmem_cache_sem);
+	list_add_tail(&skc->skc_list, &spl_kmem_cache_list);
+	up_write(&spl_kmem_cache_sem);
+
+	return (skc);
+out:
+	kfree(skc->skc_name);
+	kfree(skc);
+	return (NULL);
+}
+EXPORT_SYMBOL(spl_kmem_cache_create);
+
+/*
+ * Register a move callback for cache defragmentation.
+ * XXX: Unimplemented but harmless to stub out for now.
+ */
+void
+spl_kmem_cache_set_move(spl_kmem_cache_t *skc,
+    kmem_cbrc_t (move)(void *, void *, size_t, void *))
+{
+	ASSERT(move != NULL);
+}
+EXPORT_SYMBOL(spl_kmem_cache_set_move);
+
+/*
+ * Destroy a cache and all objects associated with the cache.
+ */
+void
+spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
+{
+	DECLARE_WAIT_QUEUE_HEAD(wq);
+	taskqid_t id;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(skc->skc_flags & (KMC_KMEM | KMC_VMEM | KMC_SLAB));
+
+	down_write(&spl_kmem_cache_sem);
+	list_del_init(&skc->skc_list);
+	up_write(&spl_kmem_cache_sem);
+
+	/* Cancel any and wait for any pending delayed tasks */
+	VERIFY(!test_and_set_bit(KMC_BIT_DESTROY, &skc->skc_flags));
+
+	spin_lock(&skc->skc_lock);
+	id = skc->skc_taskqid;
+	spin_unlock(&skc->skc_lock);
+
+	taskq_cancel_id(spl_kmem_cache_taskq, id);
+
+	/*
+	 * Wait until all current callers complete, this is mainly
+	 * to catch the case where a low memory situation triggers a
+	 * cache reaping action which races with this destroy.
+	 */
+	wait_event(wq, atomic_read(&skc->skc_ref) == 0);
+
+	if (skc->skc_flags & (KMC_KMEM | KMC_VMEM)) {
+		spl_magazine_destroy(skc);
+		spl_slab_reclaim(skc);
+	} else {
+		ASSERT(skc->skc_flags & KMC_SLAB);
+		kmem_cache_destroy(skc->skc_linux_cache);
+	}
+
+	spin_lock(&skc->skc_lock);
+
+	/*
+	 * Validate there are no objects in use and free all the
+	 * spl_kmem_slab_t, spl_kmem_obj_t, and object buffers.
+	 */
+	ASSERT3U(skc->skc_slab_alloc, ==, 0);
+	ASSERT3U(skc->skc_obj_alloc, ==, 0);
+	ASSERT3U(skc->skc_slab_total, ==, 0);
+	ASSERT3U(skc->skc_obj_total, ==, 0);
+	ASSERT3U(skc->skc_obj_emergency, ==, 0);
+	ASSERT(list_empty(&skc->skc_complete_list));
+
+	spin_unlock(&skc->skc_lock);
+
+	kfree(skc->skc_name);
+	kfree(skc);
+}
+EXPORT_SYMBOL(spl_kmem_cache_destroy);
+
+/*
+ * Allocate an object from a slab attached to the cache.  This is used to
+ * repopulate the per-cpu magazine caches in batches when they run low.
+ */
+static void *
+spl_cache_obj(spl_kmem_cache_t *skc, spl_kmem_slab_t *sks)
+{
+	spl_kmem_obj_t *sko;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(sks->sks_magic == SKS_MAGIC);
+
+	sko = list_entry(sks->sks_free_list.next, spl_kmem_obj_t, sko_list);
+	ASSERT(sko->sko_magic == SKO_MAGIC);
+	ASSERT(sko->sko_addr != NULL);
+
+	/* Remove from sks_free_list */
+	list_del_init(&sko->sko_list);
+
+	sks->sks_age = jiffies;
+	sks->sks_ref++;
+	skc->skc_obj_alloc++;
+
+	/* Track max obj usage statistics */
+	if (skc->skc_obj_alloc > skc->skc_obj_max)
+		skc->skc_obj_max = skc->skc_obj_alloc;
+
+	/* Track max slab usage statistics */
+	if (sks->sks_ref == 1) {
+		skc->skc_slab_alloc++;
+
+		if (skc->skc_slab_alloc > skc->skc_slab_max)
+			skc->skc_slab_max = skc->skc_slab_alloc;
+	}
+
+	return (sko->sko_addr);
+}
+
+/*
+ * Generic slab allocation function to run by the global work queues.
+ * It is responsible for allocating a new slab, linking it in to the list
+ * of partial slabs, and then waking any waiters.
+ */
+static int
+__spl_cache_grow(spl_kmem_cache_t *skc, int flags)
+{
+	spl_kmem_slab_t *sks;
+
+	fstrans_cookie_t cookie = spl_fstrans_mark();
+	sks = spl_slab_alloc(skc, flags);
+	spl_fstrans_unmark(cookie);
+
+	spin_lock(&skc->skc_lock);
+	if (sks) {
+		skc->skc_slab_total++;
+		skc->skc_obj_total += sks->sks_objs;
+		list_add_tail(&sks->sks_list, &skc->skc_partial_list);
+
+		smp_mb__before_atomic();
+		clear_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags);
+		smp_mb__after_atomic();
+		wake_up_all(&skc->skc_waitq);
+	}
+	spin_unlock(&skc->skc_lock);
+
+	return (sks == NULL ? -ENOMEM : 0);
+}
+
+static void
+spl_cache_grow_work(void *data)
+{
+	spl_kmem_alloc_t *ska = (spl_kmem_alloc_t *)data;
+	spl_kmem_cache_t *skc = ska->ska_cache;
+
+	(void) __spl_cache_grow(skc, ska->ska_flags);
+
+	atomic_dec(&skc->skc_ref);
+	smp_mb__before_atomic();
+	clear_bit(KMC_BIT_GROWING, &skc->skc_flags);
+	smp_mb__after_atomic();
+
+	kfree(ska);
+}
+
+/*
+ * Returns non-zero when a new slab should be available.
+ */
+static int
+spl_cache_grow_wait(spl_kmem_cache_t *skc)
+{
+	return (!test_bit(KMC_BIT_GROWING, &skc->skc_flags));
+}
+
+/*
+ * No available objects on any slabs, create a new slab.  Note that this
+ * functionality is disabled for KMC_SLAB caches which are backed by the
+ * Linux slab.
+ */
+static int
+spl_cache_grow(spl_kmem_cache_t *skc, int flags, void **obj)
+{
+	int remaining, rc = 0;
+
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT((skc->skc_flags & KMC_SLAB) == 0);
+	might_sleep();
+	*obj = NULL;
+
+	/*
+	 * Before allocating a new slab wait for any reaping to complete and
+	 * then return so the local magazine can be rechecked for new objects.
+	 */
+	if (test_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
+		rc = spl_wait_on_bit(&skc->skc_flags, KMC_BIT_REAPING,
+		    TASK_UNINTERRUPTIBLE);
+		return (rc ? rc : -EAGAIN);
+	}
+
+	/*
+	 * To reduce the overhead of context switch and improve NUMA locality,
+	 * it tries to allocate a new slab in the current process context with
+	 * KM_NOSLEEP flag. If it fails, it will launch a new taskq to do the
+	 * allocation.
+	 *
+	 * However, this can't be applied to KVM_VMEM due to a bug that
+	 * __vmalloc() doesn't honor gfp flags in page table allocation.
+	 */
+	if (!(skc->skc_flags & KMC_VMEM)) {
+		rc = __spl_cache_grow(skc, flags | KM_NOSLEEP);
+		if (rc == 0)
+			return (0);
+	}
+
+	/*
+	 * This is handled by dispatching a work request to the global work
+	 * queue.  This allows us to asynchronously allocate a new slab while
+	 * retaining the ability to safely fall back to a smaller synchronous
+	 * allocations to ensure forward progress is always maintained.
+	 */
+	if (test_and_set_bit(KMC_BIT_GROWING, &skc->skc_flags) == 0) {
+		spl_kmem_alloc_t *ska;
+
+		ska = kmalloc(sizeof (*ska), kmem_flags_convert(flags));
+		if (ska == NULL) {
+			clear_bit_unlock(KMC_BIT_GROWING, &skc->skc_flags);
+			smp_mb__after_atomic();
+			wake_up_all(&skc->skc_waitq);
+			return (-ENOMEM);
+		}
+
+		atomic_inc(&skc->skc_ref);
+		ska->ska_cache = skc;
+		ska->ska_flags = flags;
+		taskq_init_ent(&ska->ska_tqe);
+		taskq_dispatch_ent(spl_kmem_cache_taskq,
+		    spl_cache_grow_work, ska, 0, &ska->ska_tqe);
+	}
+
+	/*
+	 * The goal here is to only detect the rare case where a virtual slab
+	 * allocation has deadlocked.  We must be careful to minimize the use
+	 * of emergency objects which are more expensive to track.  Therefore,
+	 * we set a very long timeout for the asynchronous allocation and if
+	 * the timeout is reached the cache is flagged as deadlocked.  From
+	 * this point only new emergency objects will be allocated until the
+	 * asynchronous allocation completes and clears the deadlocked flag.
+	 */
+	if (test_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags)) {
+		rc = spl_emergency_alloc(skc, flags, obj);
+	} else {
+		remaining = wait_event_timeout(skc->skc_waitq,
+		    spl_cache_grow_wait(skc), HZ / 10);
+
+		if (!remaining) {
+			spin_lock(&skc->skc_lock);
+			if (test_bit(KMC_BIT_GROWING, &skc->skc_flags)) {
+				set_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags);
+				skc->skc_obj_deadlock++;
+			}
+			spin_unlock(&skc->skc_lock);
+		}
+
+		rc = -ENOMEM;
+	}
+
+	return (rc);
+}
+
+/*
+ * Refill a per-cpu magazine with objects from the slabs for this cache.
+ * Ideally the magazine can be repopulated using existing objects which have
+ * been released, however if we are unable to locate enough free objects new
+ * slabs of objects will be created.  On success NULL is returned, otherwise
+ * the address of a single emergency object is returned for use by the caller.
+ */
+static void *
+spl_cache_refill(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flags)
+{
+	spl_kmem_slab_t *sks;
+	int count = 0, rc, refill;
+	void *obj = NULL;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+
+	refill = MIN(skm->skm_refill, skm->skm_size - skm->skm_avail);
+	spin_lock(&skc->skc_lock);
+
+	while (refill > 0) {
+		/* No slabs available we may need to grow the cache */
+		if (list_empty(&skc->skc_partial_list)) {
+			spin_unlock(&skc->skc_lock);
+
+			local_irq_enable();
+			rc = spl_cache_grow(skc, flags, &obj);
+			local_irq_disable();
+
+			/* Emergency object for immediate use by caller */
+			if (rc == 0 && obj != NULL)
+				return (obj);
+
+			if (rc)
+				goto out;
+
+			/* Rescheduled to different CPU skm is not local */
+			if (skm != skc->skc_mag[smp_processor_id()])
+				goto out;
+
+			/*
+			 * Potentially rescheduled to the same CPU but
+			 * allocations may have occurred from this CPU while
+			 * we were sleeping so recalculate max refill.
+			 */
+			refill = MIN(refill, skm->skm_size - skm->skm_avail);
+
+			spin_lock(&skc->skc_lock);
+			continue;
+		}
+
+		/* Grab the next available slab */
+		sks = list_entry((&skc->skc_partial_list)->next,
+		    spl_kmem_slab_t, sks_list);
+		ASSERT(sks->sks_magic == SKS_MAGIC);
+		ASSERT(sks->sks_ref < sks->sks_objs);
+		ASSERT(!list_empty(&sks->sks_free_list));
+
+		/*
+		 * Consume as many objects as needed to refill the requested
+		 * cache.  We must also be careful not to overfill it.
+		 */
+		while (sks->sks_ref < sks->sks_objs && refill-- > 0 &&
+		    ++count) {
+			ASSERT(skm->skm_avail < skm->skm_size);
+			ASSERT(count < skm->skm_size);
+			skm->skm_objs[skm->skm_avail++] =
+			    spl_cache_obj(skc, sks);
+		}
+
+		/* Move slab to skc_complete_list when full */
+		if (sks->sks_ref == sks->sks_objs) {
+			list_del(&sks->sks_list);
+			list_add(&sks->sks_list, &skc->skc_complete_list);
+		}
+	}
+
+	spin_unlock(&skc->skc_lock);
+out:
+	return (NULL);
+}
+
+/*
+ * Release an object back to the slab from which it came.
+ */
+static void
+spl_cache_shrink(spl_kmem_cache_t *skc, void *obj)
+{
+	spl_kmem_slab_t *sks = NULL;
+	spl_kmem_obj_t *sko = NULL;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+
+	sko = spl_sko_from_obj(skc, obj);
+	ASSERT(sko->sko_magic == SKO_MAGIC);
+	sks = sko->sko_slab;
+	ASSERT(sks->sks_magic == SKS_MAGIC);
+	ASSERT(sks->sks_cache == skc);
+	list_add(&sko->sko_list, &sks->sks_free_list);
+
+	sks->sks_age = jiffies;
+	sks->sks_ref--;
+	skc->skc_obj_alloc--;
+
+	/*
+	 * Move slab to skc_partial_list when no longer full.  Slabs
+	 * are added to the head to keep the partial list is quasi-full
+	 * sorted order.  Fuller at the head, emptier at the tail.
+	 */
+	if (sks->sks_ref == (sks->sks_objs - 1)) {
+		list_del(&sks->sks_list);
+		list_add(&sks->sks_list, &skc->skc_partial_list);
+	}
+
+	/*
+	 * Move empty slabs to the end of the partial list so
+	 * they can be easily found and freed during reclamation.
+	 */
+	if (sks->sks_ref == 0) {
+		list_del(&sks->sks_list);
+		list_add_tail(&sks->sks_list, &skc->skc_partial_list);
+		skc->skc_slab_alloc--;
+	}
+}
+
+/*
+ * Allocate an object from the per-cpu magazine, or if the magazine
+ * is empty directly allocate from a slab and repopulate the magazine.
+ */
+void *
+spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags)
+{
+	spl_kmem_magazine_t *skm;
+	void *obj = NULL;
+
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
+
+	/*
+	 * Allocate directly from a Linux slab.  All optimizations are left
+	 * to the underlying cache we only need to guarantee that KM_SLEEP
+	 * callers will never fail.
+	 */
+	if (skc->skc_flags & KMC_SLAB) {
+		struct kmem_cache *slc = skc->skc_linux_cache;
+		do {
+			obj = kmem_cache_alloc(slc, kmem_flags_convert(flags));
+		} while ((obj == NULL) && !(flags & KM_NOSLEEP));
+
+		goto ret;
+	}
+
+	local_irq_disable();
+
+restart:
+	/*
+	 * Safe to update per-cpu structure without lock, but
+	 * in the restart case we must be careful to reacquire
+	 * the local magazine since this may have changed
+	 * when we need to grow the cache.
+	 */
+	skm = skc->skc_mag[smp_processor_id()];
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+
+	if (likely(skm->skm_avail)) {
+		/* Object available in CPU cache, use it */
+		obj = skm->skm_objs[--skm->skm_avail];
+		skm->skm_age = jiffies;
+	} else {
+		obj = spl_cache_refill(skc, skm, flags);
+		if ((obj == NULL) && !(flags & KM_NOSLEEP))
+			goto restart;
+
+		local_irq_enable();
+		goto ret;
+	}
+
+	local_irq_enable();
+	ASSERT(obj);
+	ASSERT(IS_P2ALIGNED(obj, skc->skc_obj_align));
+
+ret:
+	/* Pre-emptively migrate object to CPU L1 cache */
+	if (obj) {
+		if (obj && skc->skc_ctor)
+			skc->skc_ctor(obj, skc->skc_private, flags);
+		else
+			prefetchw(obj);
+	}
+
+	return (obj);
+}
+EXPORT_SYMBOL(spl_kmem_cache_alloc);
+
+/*
+ * Free an object back to the local per-cpu magazine, there is no
+ * guarantee that this is the same magazine the object was originally
+ * allocated from.  We may need to flush entire from the magazine
+ * back to the slabs to make space.
+ */
+void
+spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
+{
+	spl_kmem_magazine_t *skm;
+	unsigned long flags;
+	int do_reclaim = 0;
+	int do_emergency = 0;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
+
+	/*
+	 * Run the destructor
+	 */
+	if (skc->skc_dtor)
+		skc->skc_dtor(obj, skc->skc_private);
+
+	/*
+	 * Free the object from the Linux underlying Linux slab.
+	 */
+	if (skc->skc_flags & KMC_SLAB) {
+		kmem_cache_free(skc->skc_linux_cache, obj);
+		return;
+	}
+
+	/*
+	 * While a cache has outstanding emergency objects all freed objects
+	 * must be checked.  However, since emergency objects will never use
+	 * a virtual address these objects can be safely excluded as an
+	 * optimization.
+	 */
+	if (!is_vmalloc_addr(obj)) {
+		spin_lock(&skc->skc_lock);
+		do_emergency = (skc->skc_obj_emergency > 0);
+		spin_unlock(&skc->skc_lock);
+
+		if (do_emergency && (spl_emergency_free(skc, obj) == 0))
+			return;
+	}
+
+	local_irq_save(flags);
+
+	/*
+	 * Safe to update per-cpu structure without lock, but
+	 * no remote memory allocation tracking is being performed
+	 * it is entirely possible to allocate an object from one
+	 * CPU cache and return it to another.
+	 */
+	skm = skc->skc_mag[smp_processor_id()];
+	ASSERT(skm->skm_magic == SKM_MAGIC);
+
+	/*
+	 * Per-CPU cache full, flush it to make space for this object,
+	 * this may result in an empty slab which can be reclaimed once
+	 * interrupts are re-enabled.
+	 */
+	if (unlikely(skm->skm_avail >= skm->skm_size)) {
+		spl_cache_flush(skc, skm, skm->skm_refill);
+		do_reclaim = 1;
+	}
+
+	/* Available space in cache, use it */
+	skm->skm_objs[skm->skm_avail++] = obj;
+
+	local_irq_restore(flags);
+
+	if (do_reclaim)
+		spl_slab_reclaim(skc);
+}
+EXPORT_SYMBOL(spl_kmem_cache_free);
+
+/*
+ * The generic shrinker function for all caches.  Under Linux a shrinker
+ * may not be tightly coupled with a slab cache.  In fact Linux always
+ * systematically tries calling all registered shrinker callbacks which
+ * report that they contain unused objects.  Because of this we only
+ * register one shrinker function in the shim layer for all slab caches.
+ * We always attempt to shrink all caches when this generic shrinker
+ * is called.
+ *
+ * If sc->nr_to_scan is zero, the caller is requesting a query of the
+ * number of objects which can potentially be freed.  If it is nonzero,
+ * the request is to free that many objects.
+ *
+ * Linux kernels >= 3.12 have the count_objects and scan_objects callbacks
+ * in struct shrinker and also require the shrinker to return the number
+ * of objects freed.
+ *
+ * Older kernels require the shrinker to return the number of freeable
+ * objects following the freeing of nr_to_free.
+ *
+ * Linux semantics differ from those under Solaris, which are to
+ * free all available objects which may (and probably will) be more
+ * objects than the requested nr_to_scan.
+ */
+static spl_shrinker_t
+__spl_kmem_cache_generic_shrinker(struct shrinker *shrink,
+    struct shrink_control *sc)
+{
+	spl_kmem_cache_t *skc;
+	int alloc = 0;
+
+	/*
+	 * No shrinking in a transaction context.  Can cause deadlocks.
+	 */
+	if (sc->nr_to_scan && spl_fstrans_check())
+		return (SHRINK_STOP);
+
+	down_read(&spl_kmem_cache_sem);
+	list_for_each_entry(skc, &spl_kmem_cache_list, skc_list) {
+		if (sc->nr_to_scan) {
+#ifdef HAVE_SPLIT_SHRINKER_CALLBACK
+			uint64_t oldalloc = skc->skc_obj_alloc;
+			spl_kmem_cache_reap_now(skc,
+			    MAX(sc->nr_to_scan>>fls64(skc->skc_slab_objs), 1));
+			if (oldalloc > skc->skc_obj_alloc)
+				alloc += oldalloc - skc->skc_obj_alloc;
+#else
+			spl_kmem_cache_reap_now(skc,
+			    MAX(sc->nr_to_scan>>fls64(skc->skc_slab_objs), 1));
+			alloc += skc->skc_obj_alloc;
+#endif /* HAVE_SPLIT_SHRINKER_CALLBACK */
+		} else {
+			/* Request to query number of freeable objects */
+			alloc += skc->skc_obj_alloc;
+		}
+	}
+	up_read(&spl_kmem_cache_sem);
+
+	/*
+	 * When KMC_RECLAIM_ONCE is set allow only a single reclaim pass.
+	 * This functionality only exists to work around a rare issue where
+	 * shrink_slabs() is repeatedly invoked by many cores causing the
+	 * system to thrash.
+	 */
+	if ((spl_kmem_cache_reclaim & KMC_RECLAIM_ONCE) && sc->nr_to_scan)
+		return (SHRINK_STOP);
+
+	return (MAX(alloc, 0));
+}
+
+SPL_SHRINKER_CALLBACK_WRAPPER(spl_kmem_cache_generic_shrinker);
+
+/*
+ * Call the registered reclaim function for a cache.  Depending on how
+ * many and which objects are released it may simply repopulate the
+ * local magazine which will then need to age-out.  Objects which cannot
+ * fit in the magazine we will be released back to their slabs which will
+ * also need to age out before being release.  This is all just best
+ * effort and we do not want to thrash creating and destroying slabs.
+ */
+void
+spl_kmem_cache_reap_now(spl_kmem_cache_t *skc, int count)
+{
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+	ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
+
+	atomic_inc(&skc->skc_ref);
+
+	/*
+	 * Execute the registered reclaim callback if it exists.
+	 */
+	if (skc->skc_flags & KMC_SLAB) {
+		if (skc->skc_reclaim)
+			skc->skc_reclaim(skc->skc_private);
+		goto out;
+	}
+
+	/*
+	 * Prevent concurrent cache reaping when contended.
+	 */
+	if (test_and_set_bit(KMC_BIT_REAPING, &skc->skc_flags))
+		goto out;
+
+	/*
+	 * When a reclaim function is available it may be invoked repeatedly
+	 * until at least a single slab can be freed.  This ensures that we
+	 * do free memory back to the system.  This helps minimize the chance
+	 * of an OOM event when the bulk of memory is used by the slab.
+	 *
+	 * When free slabs are already available the reclaim callback will be
+	 * skipped.  Additionally, if no forward progress is detected despite
+	 * a reclaim function the cache will be skipped to avoid deadlock.
+	 *
+	 * Longer term this would be the correct place to add the code which
+	 * repacks the slabs in order minimize fragmentation.
+	 */
+	if (skc->skc_reclaim) {
+		uint64_t objects = UINT64_MAX;
+		int do_reclaim;
+
+		do {
+			spin_lock(&skc->skc_lock);
+			do_reclaim =
+			    (skc->skc_slab_total > 0) &&
+			    ((skc->skc_slab_total-skc->skc_slab_alloc) == 0) &&
+			    (skc->skc_obj_alloc < objects);
+
+			objects = skc->skc_obj_alloc;
+			spin_unlock(&skc->skc_lock);
+
+			if (do_reclaim)
+				skc->skc_reclaim(skc->skc_private);
+
+		} while (do_reclaim);
+	}
+
+	/* Reclaim from the magazine and free all now empty slabs. */
+	if (spl_kmem_cache_expire & KMC_EXPIRE_MEM) {
+		spl_kmem_magazine_t *skm;
+		unsigned long irq_flags;
+
+		local_irq_save(irq_flags);
+		skm = skc->skc_mag[smp_processor_id()];
+		spl_cache_flush(skc, skm, skm->skm_avail);
+		local_irq_restore(irq_flags);
+	}
+
+	spl_slab_reclaim(skc);
+	clear_bit_unlock(KMC_BIT_REAPING, &skc->skc_flags);
+	smp_mb__after_atomic();
+	wake_up_bit(&skc->skc_flags, KMC_BIT_REAPING);
+out:
+	atomic_dec(&skc->skc_ref);
+}
+EXPORT_SYMBOL(spl_kmem_cache_reap_now);
+
+/*
+ * Reap all free slabs from all registered caches.
+ */
+void
+spl_kmem_reap(void)
+{
+	struct shrink_control sc;
+
+	sc.nr_to_scan = KMC_REAP_CHUNK;
+	sc.gfp_mask = GFP_KERNEL;
+
+	(void) __spl_kmem_cache_generic_shrinker(NULL, &sc);
+}
+EXPORT_SYMBOL(spl_kmem_reap);
+
+int
+spl_kmem_cache_init(void)
+{
+	init_rwsem(&spl_kmem_cache_sem);
+	INIT_LIST_HEAD(&spl_kmem_cache_list);
+	spl_kmem_cache_taskq = taskq_create("spl_kmem_cache",
+	    spl_kmem_cache_kmem_threads, maxclsyspri,
+	    spl_kmem_cache_kmem_threads * 8, INT_MAX,
+	    TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
+	spl_register_shrinker(&spl_kmem_cache_shrinker);
+
+	return (0);
+}
+
+void
+spl_kmem_cache_fini(void)
+{
+	spl_unregister_shrinker(&spl_kmem_cache_shrinker);
+	taskq_destroy(spl_kmem_cache_taskq);
+}
diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
new file mode 100644
index 000000000..e0d551041
--- /dev/null
+++ b/module/spl/spl-kmem.c
@@ -0,0 +1,567 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/debug.h>
+#include <sys/sysmacros.h>
+#include <sys/kmem.h>
+#include <sys/vmem.h>
+#include <linux/mm.h>
+#include <linux/ratelimit.h>
+
+/*
+ * As a general rule kmem_alloc() allocations should be small, preferably
+ * just a few pages since they must by physically contiguous.  Therefore, a
+ * rate limited warning will be printed to the console for any kmem_alloc()
+ * which exceeds a reasonable threshold.
+ *
+ * The default warning threshold is set to sixteen pages but capped at 64K to
+ * accommodate systems using large pages.  This value was selected to be small
+ * enough to ensure the largest allocations are quickly noticed and fixed.
+ * But large enough to avoid logging any warnings when a allocation size is
+ * larger than optimal but not a serious concern.  Since this value is tunable,
+ * developers are encouraged to set it lower when testing so any new largish
+ * allocations are quickly caught.  These warnings may be disabled by setting
+ * the threshold to zero.
+ */
+/* BEGIN CSTYLED */
+unsigned int spl_kmem_alloc_warn = MIN(16 * PAGE_SIZE, 64 * 1024);
+module_param(spl_kmem_alloc_warn, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_alloc_warn,
+	"Warning threshold in bytes for a kmem_alloc()");
+EXPORT_SYMBOL(spl_kmem_alloc_warn);
+
+/*
+ * Large kmem_alloc() allocations will fail if they exceed KMALLOC_MAX_SIZE.
+ * Allocations which are marginally smaller than this limit may succeed but
+ * should still be avoided due to the expense of locating a contiguous range
+ * of free pages.  Therefore, a maximum kmem size with reasonable safely
+ * margin of 4x is set.  Kmem_alloc() allocations larger than this maximum
+ * will quickly fail.  Vmem_alloc() allocations less than or equal to this
+ * value will use kmalloc(), but shift to vmalloc() when exceeding this value.
+ */
+unsigned int spl_kmem_alloc_max = (KMALLOC_MAX_SIZE >> 2);
+module_param(spl_kmem_alloc_max, uint, 0644);
+MODULE_PARM_DESC(spl_kmem_alloc_max,
+	"Maximum size in bytes for a kmem_alloc()");
+EXPORT_SYMBOL(spl_kmem_alloc_max);
+/* END CSTYLED */
+
+int
+kmem_debugging(void)
+{
+	return (0);
+}
+EXPORT_SYMBOL(kmem_debugging);
+
+char *
+kmem_vasprintf(const char *fmt, va_list ap)
+{
+	va_list aq;
+	char *ptr;
+
+	do {
+		va_copy(aq, ap);
+		ptr = kvasprintf(kmem_flags_convert(KM_SLEEP), fmt, aq);
+		va_end(aq);
+	} while (ptr == NULL);
+
+	return (ptr);
+}
+EXPORT_SYMBOL(kmem_vasprintf);
+
+char *
+kmem_asprintf(const char *fmt, ...)
+{
+	va_list ap;
+	char *ptr;
+
+	do {
+		va_start(ap, fmt);
+		ptr = kvasprintf(kmem_flags_convert(KM_SLEEP), fmt, ap);
+		va_end(ap);
+	} while (ptr == NULL);
+
+	return (ptr);
+}
+EXPORT_SYMBOL(kmem_asprintf);
+
+static char *
+__strdup(const char *str, int flags)
+{
+	char *ptr;
+	int n;
+
+	n = strlen(str);
+	ptr = kmalloc(n + 1, kmem_flags_convert(flags));
+	if (ptr)
+		memcpy(ptr, str, n + 1);
+
+	return (ptr);
+}
+
+char *
+strdup(const char *str)
+{
+	return (__strdup(str, KM_SLEEP));
+}
+EXPORT_SYMBOL(strdup);
+
+void
+strfree(char *str)
+{
+	kfree(str);
+}
+EXPORT_SYMBOL(strfree);
+
+/*
+ * Limit the number of large allocation stack traces dumped to not more than
+ * 5 every 60 seconds to prevent denial-of-service attacks from debug code.
+ */
+DEFINE_RATELIMIT_STATE(kmem_alloc_ratelimit_state, 60 * HZ, 5);
+
+/*
+ * General purpose unified implementation of kmem_alloc(). It is an
+ * amalgamation of Linux and Illumos allocator design. It should never be
+ * exported to ensure that code using kmem_alloc()/kmem_zalloc() remains
+ * relatively portable.  Consumers may only access this function through
+ * wrappers that enforce the common flags to ensure portability.
+ */
+inline void *
+spl_kmem_alloc_impl(size_t size, int flags, int node)
+{
+	gfp_t lflags = kmem_flags_convert(flags);
+	int use_vmem = 0;
+	void *ptr;
+
+	/*
+	 * Log abnormally large allocations and rate limit the console output.
+	 * Allocations larger than spl_kmem_alloc_warn should be performed
+	 * through the vmem_alloc()/vmem_zalloc() interfaces.
+	 */
+	if ((spl_kmem_alloc_warn > 0) && (size > spl_kmem_alloc_warn) &&
+	    !(flags & KM_VMEM) && __ratelimit(&kmem_alloc_ratelimit_state)) {
+		printk(KERN_WARNING
+		    "Large kmem_alloc(%lu, 0x%x), please file an issue at:\n"
+		    "https://github.com/zfsonlinux/zfs/issues/new\n",
+		    (unsigned long)size, flags);
+		dump_stack();
+	}
+
+	/*
+	 * Use a loop because kmalloc_node() can fail when GFP_KERNEL is used
+	 * unlike kmem_alloc() with KM_SLEEP on Illumos.
+	 */
+	do {
+		/*
+		 * Calling kmalloc_node() when the size >= spl_kmem_alloc_max
+		 * is unsafe.  This must fail for all for kmem_alloc() and
+		 * kmem_zalloc() callers.
+		 *
+		 * For vmem_alloc() and vmem_zalloc() callers it is permissible
+		 * to use __vmalloc().  However, in general use of __vmalloc()
+		 * is strongly discouraged because a global lock must be
+		 * acquired.  Contention on this lock can significantly
+		 * impact performance so frequently manipulating the virtual
+		 * address space is strongly discouraged.
+		 */
+		if ((size > spl_kmem_alloc_max) || use_vmem) {
+			if (flags & KM_VMEM) {
+				ptr = __vmalloc(size, lflags, PAGE_KERNEL);
+			} else {
+				return (NULL);
+			}
+		} else {
+			ptr = kmalloc_node(size, lflags, node);
+		}
+
+		if (likely(ptr) || (flags & KM_NOSLEEP))
+			return (ptr);
+
+		/*
+		 * For vmem_alloc() and vmem_zalloc() callers retry immediately
+		 * using __vmalloc() which is unlikely to fail.
+		 */
+		if ((flags & KM_VMEM) && (use_vmem == 0))  {
+			use_vmem = 1;
+			continue;
+		}
+
+		if (unlikely(__ratelimit(&kmem_alloc_ratelimit_state))) {
+			printk(KERN_WARNING
+			    "Possible memory allocation deadlock: "
+			    "size=%lu lflags=0x%x",
+			    (unsigned long)size, lflags);
+			dump_stack();
+		}
+
+		/*
+		 * Use cond_resched() instead of congestion_wait() to avoid
+		 * deadlocking systems where there are no block devices.
+		 */
+		cond_resched();
+	} while (1);
+
+	return (NULL);
+}
+
+inline void
+spl_kmem_free_impl(const void *buf, size_t size)
+{
+	if (is_vmalloc_addr(buf))
+		vfree(buf);
+	else
+		kfree(buf);
+}
+
+/*
+ * Memory allocation and accounting for kmem_* * style allocations.  When
+ * DEBUG_KMEM is enabled the total memory allocated will be tracked and
+ * any memory leaked will be reported during module unload.
+ *
+ * ./configure --enable-debug-kmem
+ */
+#ifdef DEBUG_KMEM
+
+/* Shim layer memory accounting */
+#ifdef HAVE_ATOMIC64_T
+atomic64_t kmem_alloc_used = ATOMIC64_INIT(0);
+unsigned long long kmem_alloc_max = 0;
+#else  /* HAVE_ATOMIC64_T */
+atomic_t kmem_alloc_used = ATOMIC_INIT(0);
+unsigned long long kmem_alloc_max = 0;
+#endif /* HAVE_ATOMIC64_T */
+
+EXPORT_SYMBOL(kmem_alloc_used);
+EXPORT_SYMBOL(kmem_alloc_max);
+
+inline void *
+spl_kmem_alloc_debug(size_t size, int flags, int node)
+{
+	void *ptr;
+
+	ptr = spl_kmem_alloc_impl(size, flags, node);
+	if (ptr) {
+		kmem_alloc_used_add(size);
+		if (unlikely(kmem_alloc_used_read() > kmem_alloc_max))
+			kmem_alloc_max = kmem_alloc_used_read();
+	}
+
+	return (ptr);
+}
+
+inline void
+spl_kmem_free_debug(const void *ptr, size_t size)
+{
+	kmem_alloc_used_sub(size);
+	spl_kmem_free_impl(ptr, size);
+}
+
+/*
+ * When DEBUG_KMEM_TRACKING is enabled not only will total bytes be tracked
+ * but also the location of every alloc and free.  When the SPL module is
+ * unloaded a list of all leaked addresses and where they were allocated
+ * will be dumped to the console.  Enabling this feature has a significant
+ * impact on performance but it makes finding memory leaks straight forward.
+ *
+ * Not surprisingly with debugging enabled the xmem_locks are very highly
+ * contended particularly on xfree().  If we want to run with this detailed
+ * debugging enabled for anything other than debugging  we need to minimize
+ * the contention by moving to a lock per xmem_table entry model.
+ *
+ * ./configure --enable-debug-kmem-tracking
+ */
+#ifdef DEBUG_KMEM_TRACKING
+
+#include <linux/hash.h>
+#include <linux/ctype.h>
+
+#define	KMEM_HASH_BITS		10
+#define	KMEM_TABLE_SIZE		(1 << KMEM_HASH_BITS)
+
+typedef struct kmem_debug {
+	struct hlist_node kd_hlist;	/* Hash node linkage */
+	struct list_head kd_list;	/* List of all allocations */
+	void *kd_addr;			/* Allocation pointer */
+	size_t kd_size;			/* Allocation size */
+	const char *kd_func;		/* Allocation function */
+	int kd_line;			/* Allocation line */
+} kmem_debug_t;
+
+static spinlock_t kmem_lock;
+static struct hlist_head kmem_table[KMEM_TABLE_SIZE];
+static struct list_head kmem_list;
+
+static kmem_debug_t *
+kmem_del_init(spinlock_t *lock, struct hlist_head *table,
+    int bits, const void *addr)
+{
+	struct hlist_head *head;
+	struct hlist_node *node;
+	struct kmem_debug *p;
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	head = &table[hash_ptr((void *)addr, bits)];
+	hlist_for_each(node, head) {
+		p = list_entry(node, struct kmem_debug, kd_hlist);
+		if (p->kd_addr == addr) {
+			hlist_del_init(&p->kd_hlist);
+			list_del_init(&p->kd_list);
+			spin_unlock_irqrestore(lock, flags);
+			return (p);
+		}
+	}
+
+	spin_unlock_irqrestore(lock, flags);
+
+	return (NULL);
+}
+
+inline void *
+spl_kmem_alloc_track(size_t size, int flags,
+    const char *func, int line, int node)
+{
+	void *ptr = NULL;
+	kmem_debug_t *dptr;
+	unsigned long irq_flags;
+
+	dptr = kmalloc(sizeof (kmem_debug_t), kmem_flags_convert(flags));
+	if (dptr == NULL)
+		return (NULL);
+
+	dptr->kd_func = __strdup(func, flags);
+	if (dptr->kd_func == NULL) {
+		kfree(dptr);
+		return (NULL);
+	}
+
+	ptr = spl_kmem_alloc_debug(size, flags, node);
+	if (ptr == NULL) {
+		kfree(dptr->kd_func);
+		kfree(dptr);
+		return (NULL);
+	}
+
+	INIT_HLIST_NODE(&dptr->kd_hlist);
+	INIT_LIST_HEAD(&dptr->kd_list);
+
+	dptr->kd_addr = ptr;
+	dptr->kd_size = size;
+	dptr->kd_line = line;
+
+	spin_lock_irqsave(&kmem_lock, irq_flags);
+	hlist_add_head(&dptr->kd_hlist,
+	    &kmem_table[hash_ptr(ptr, KMEM_HASH_BITS)]);
+	list_add_tail(&dptr->kd_list, &kmem_list);
+	spin_unlock_irqrestore(&kmem_lock, irq_flags);
+
+	return (ptr);
+}
+
+inline void
+spl_kmem_free_track(const void *ptr, size_t size)
+{
+	kmem_debug_t *dptr;
+
+	/* Ignore NULL pointer since we haven't tracked it at all */
+	if (ptr == NULL)
+		return;
+
+	/* Must exist in hash due to kmem_alloc() */
+	dptr = kmem_del_init(&kmem_lock, kmem_table, KMEM_HASH_BITS, ptr);
+	ASSERT3P(dptr, !=, NULL);
+	ASSERT3S(dptr->kd_size, ==, size);
+
+	kfree(dptr->kd_func);
+	kfree(dptr);
+
+	spl_kmem_free_debug(ptr, size);
+}
+#endif /* DEBUG_KMEM_TRACKING */
+#endif /* DEBUG_KMEM */
+
+/*
+ * Public kmem_alloc(), kmem_zalloc() and kmem_free() interfaces.
+ */
+void *
+spl_kmem_alloc(size_t size, int flags, const char *func, int line)
+{
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
+#else
+	return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
+#endif
+}
+EXPORT_SYMBOL(spl_kmem_alloc);
+
+void *
+spl_kmem_zalloc(size_t size, int flags, const char *func, int line)
+{
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+
+	flags |= KM_ZERO;
+
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
+#else
+	return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
+#endif
+}
+EXPORT_SYMBOL(spl_kmem_zalloc);
+
+void
+spl_kmem_free(const void *buf, size_t size)
+{
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_free_impl(buf, size));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_free_debug(buf, size));
+#else
+	return (spl_kmem_free_track(buf, size));
+#endif
+}
+EXPORT_SYMBOL(spl_kmem_free);
+
+#if defined(DEBUG_KMEM) && defined(DEBUG_KMEM_TRACKING)
+static char *
+spl_sprintf_addr(kmem_debug_t *kd, char *str, int len, int min)
+{
+	int size = ((len - 1) < kd->kd_size) ? (len - 1) : kd->kd_size;
+	int i, flag = 1;
+
+	ASSERT(str != NULL && len >= 17);
+	memset(str, 0, len);
+
+	/*
+	 * Check for a fully printable string, and while we are at
+	 * it place the printable characters in the passed buffer.
+	 */
+	for (i = 0; i < size; i++) {
+		str[i] = ((char *)(kd->kd_addr))[i];
+		if (isprint(str[i])) {
+			continue;
+		} else {
+			/*
+			 * Minimum number of printable characters found
+			 * to make it worthwhile to print this as ascii.
+			 */
+			if (i > min)
+				break;
+
+			flag = 0;
+			break;
+		}
+	}
+
+	if (!flag) {
+		sprintf(str, "%02x%02x%02x%02x%02x%02x%02x%02x",
+		    *((uint8_t *)kd->kd_addr),
+		    *((uint8_t *)kd->kd_addr + 2),
+		    *((uint8_t *)kd->kd_addr + 4),
+		    *((uint8_t *)kd->kd_addr + 6),
+		    *((uint8_t *)kd->kd_addr + 8),
+		    *((uint8_t *)kd->kd_addr + 10),
+		    *((uint8_t *)kd->kd_addr + 12),
+		    *((uint8_t *)kd->kd_addr + 14));
+	}
+
+	return (str);
+}
+
+static int
+spl_kmem_init_tracking(struct list_head *list, spinlock_t *lock, int size)
+{
+	int i;
+
+	spin_lock_init(lock);
+	INIT_LIST_HEAD(list);
+
+	for (i = 0; i < size; i++)
+		INIT_HLIST_HEAD(&kmem_table[i]);
+
+	return (0);
+}
+
+static void
+spl_kmem_fini_tracking(struct list_head *list, spinlock_t *lock)
+{
+	unsigned long flags;
+	kmem_debug_t *kd;
+	char str[17];
+
+	spin_lock_irqsave(lock, flags);
+	if (!list_empty(list))
+		printk(KERN_WARNING "%-16s %-5s %-16s %s:%s\n", "address",
+		    "size", "data", "func", "line");
+
+	list_for_each_entry(kd, list, kd_list) {
+		printk(KERN_WARNING "%p %-5d %-16s %s:%d\n", kd->kd_addr,
+		    (int)kd->kd_size, spl_sprintf_addr(kd, str, 17, 8),
+		    kd->kd_func, kd->kd_line);
+	}
+
+	spin_unlock_irqrestore(lock, flags);
+}
+#endif /* DEBUG_KMEM && DEBUG_KMEM_TRACKING */
+
+int
+spl_kmem_init(void)
+{
+#ifdef DEBUG_KMEM
+	kmem_alloc_used_set(0);
+
+#ifdef DEBUG_KMEM_TRACKING
+	spl_kmem_init_tracking(&kmem_list, &kmem_lock, KMEM_TABLE_SIZE);
+#endif /* DEBUG_KMEM_TRACKING */
+#endif /* DEBUG_KMEM */
+
+	return (0);
+}
+
+void
+spl_kmem_fini(void)
+{
+#ifdef DEBUG_KMEM
+	/*
+	 * Display all unreclaimed memory addresses, including the
+	 * allocation size and the first few bytes of what's located
+	 * at that address to aid in debugging.  Performance is not
+	 * a serious concern here since it is module unload time.
+	 */
+	if (kmem_alloc_used_read() != 0)
+		printk(KERN_WARNING "kmem leaked %ld/%llu bytes\n",
+		    (unsigned long)kmem_alloc_used_read(), kmem_alloc_max);
+
+#ifdef DEBUG_KMEM_TRACKING
+	spl_kmem_fini_tracking(&kmem_list, &kmem_lock);
+#endif /* DEBUG_KMEM_TRACKING */
+#endif /* DEBUG_KMEM */
+}
diff --git a/module/spl/spl-kobj.c b/module/spl/spl-kobj.c
new file mode 100644
index 000000000..7019369bd
--- /dev/null
+++ b/module/spl/spl-kobj.c
@@ -0,0 +1,86 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Kobj Implementation.
+ */
+
+#include <sys/kobj.h>
+
+struct _buf *
+kobj_open_file(const char *name)
+{
+	struct _buf *file;
+	vnode_t *vp;
+	int rc;
+
+	file = kmalloc(sizeof (_buf_t), kmem_flags_convert(KM_SLEEP));
+	if (file == NULL)
+		return ((_buf_t *)-1UL);
+
+	if ((rc = vn_open(name, UIO_SYSSPACE, FREAD, 0644, &vp, 0, 0))) {
+		kfree(file);
+		return ((_buf_t *)-1UL);
+	}
+
+	file->vp = vp;
+
+	return (file);
+} /* kobj_open_file() */
+EXPORT_SYMBOL(kobj_open_file);
+
+void
+kobj_close_file(struct _buf *file)
+{
+	VOP_CLOSE(file->vp, 0, 0, 0, 0, 0);
+	kfree(file);
+} /* kobj_close_file() */
+EXPORT_SYMBOL(kobj_close_file);
+
+int
+kobj_read_file(struct _buf *file, char *buf, unsigned size, unsigned off)
+{
+	ssize_t resid;
+
+	if (vn_rdwr(UIO_READ, file->vp, buf, size, (offset_t)off,
+	    UIO_SYSSPACE, 0, 0, 0, &resid) != 0)
+		return (-1);
+
+	return (size - resid);
+} /* kobj_read_file() */
+EXPORT_SYMBOL(kobj_read_file);
+
+int
+kobj_get_filesize(struct _buf *file, uint64_t *size)
+{
+	vattr_t vap;
+	int rc;
+
+	rc = VOP_GETATTR(file->vp, &vap, 0, 0, NULL);
+	if (rc)
+		return (rc);
+
+	*size = vap.va_size;
+
+	return (rc);
+} /* kobj_get_filesize() */
+EXPORT_SYMBOL(kobj_get_filesize);
diff --git a/module/spl/spl-kstat.c b/module/spl/spl-kstat.c
new file mode 100644
index 000000000..bcbff94a6
--- /dev/null
+++ b/module/spl/spl-kstat.c
@@ -0,0 +1,733 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Kstat Implementation.
+ */
+
+#include <linux/seq_file.h>
+#include <sys/kstat.h>
+#include <sys/vmem.h>
+#include <sys/cmn_err.h>
+#include <sys/sysmacros.h>
+
+#ifndef HAVE_PDE_DATA
+#define	PDE_DATA(x) (PDE(x)->data)
+#endif
+
+static kmutex_t kstat_module_lock;
+static struct list_head kstat_module_list;
+static kid_t kstat_id;
+
+static int
+kstat_resize_raw(kstat_t *ksp)
+{
+	if (ksp->ks_raw_bufsize == KSTAT_RAW_MAX)
+		return (ENOMEM);
+
+	vmem_free(ksp->ks_raw_buf, ksp->ks_raw_bufsize);
+	ksp->ks_raw_bufsize = MIN(ksp->ks_raw_bufsize * 2, KSTAT_RAW_MAX);
+	ksp->ks_raw_buf = vmem_alloc(ksp->ks_raw_bufsize, KM_SLEEP);
+
+	return (0);
+}
+
+void
+kstat_waitq_enter(kstat_io_t *kiop)
+{
+	hrtime_t new, delta;
+	ulong_t wcnt;
+
+	new = gethrtime();
+	delta = new - kiop->wlastupdate;
+	kiop->wlastupdate = new;
+	wcnt = kiop->wcnt++;
+	if (wcnt != 0) {
+		kiop->wlentime += delta * wcnt;
+		kiop->wtime += delta;
+	}
+}
+EXPORT_SYMBOL(kstat_waitq_enter);
+
+void
+kstat_waitq_exit(kstat_io_t *kiop)
+{
+	hrtime_t new, delta;
+	ulong_t wcnt;
+
+	new = gethrtime();
+	delta = new - kiop->wlastupdate;
+	kiop->wlastupdate = new;
+	wcnt = kiop->wcnt--;
+	ASSERT((int)wcnt > 0);
+	kiop->wlentime += delta * wcnt;
+	kiop->wtime += delta;
+}
+EXPORT_SYMBOL(kstat_waitq_exit);
+
+void
+kstat_runq_enter(kstat_io_t *kiop)
+{
+	hrtime_t new, delta;
+	ulong_t rcnt;
+
+	new = gethrtime();
+	delta = new - kiop->rlastupdate;
+	kiop->rlastupdate = new;
+	rcnt = kiop->rcnt++;
+	if (rcnt != 0) {
+		kiop->rlentime += delta * rcnt;
+		kiop->rtime += delta;
+	}
+}
+EXPORT_SYMBOL(kstat_runq_enter);
+
+void
+kstat_runq_exit(kstat_io_t *kiop)
+{
+	hrtime_t new, delta;
+	ulong_t rcnt;
+
+	new = gethrtime();
+	delta = new - kiop->rlastupdate;
+	kiop->rlastupdate = new;
+	rcnt = kiop->rcnt--;
+	ASSERT((int)rcnt > 0);
+	kiop->rlentime += delta * rcnt;
+	kiop->rtime += delta;
+}
+EXPORT_SYMBOL(kstat_runq_exit);
+
+static int
+kstat_seq_show_headers(struct seq_file *f)
+{
+	kstat_t *ksp = (kstat_t *)f->private;
+	int rc = 0;
+
+	ASSERT(ksp->ks_magic == KS_MAGIC);
+
+	seq_printf(f, "%d %d 0x%02x %d %d %lld %lld\n",
+	    ksp->ks_kid, ksp->ks_type, ksp->ks_flags,
+	    ksp->ks_ndata, (int)ksp->ks_data_size,
+	    ksp->ks_crtime, ksp->ks_snaptime);
+
+	switch (ksp->ks_type) {
+		case KSTAT_TYPE_RAW:
+restart:
+			if (ksp->ks_raw_ops.headers) {
+				rc = ksp->ks_raw_ops.headers(
+				    ksp->ks_raw_buf, ksp->ks_raw_bufsize);
+				if (rc == ENOMEM && !kstat_resize_raw(ksp))
+					goto restart;
+				if (!rc)
+					seq_puts(f, ksp->ks_raw_buf);
+			} else {
+				seq_printf(f, "raw data\n");
+			}
+			break;
+		case KSTAT_TYPE_NAMED:
+			seq_printf(f, "%-31s %-4s %s\n",
+			    "name", "type", "data");
+			break;
+		case KSTAT_TYPE_INTR:
+			seq_printf(f, "%-8s %-8s %-8s %-8s %-8s\n",
+			    "hard", "soft", "watchdog",
+			    "spurious", "multsvc");
+			break;
+		case KSTAT_TYPE_IO:
+			seq_printf(f,
+			    "%-8s %-8s %-8s %-8s %-8s %-8s "
+			    "%-8s %-8s %-8s %-8s %-8s %-8s\n",
+			    "nread", "nwritten", "reads", "writes",
+			    "wtime", "wlentime", "wupdate",
+			    "rtime", "rlentime", "rupdate",
+			    "wcnt", "rcnt");
+			break;
+		case KSTAT_TYPE_TIMER:
+			seq_printf(f,
+			    "%-31s %-8s "
+			    "%-8s %-8s %-8s %-8s %-8s\n",
+			    "name", "events", "elapsed",
+			    "min", "max", "start", "stop");
+			break;
+		default:
+			PANIC("Undefined kstat type %d\n", ksp->ks_type);
+	}
+
+	return (-rc);
+}
+
+static int
+kstat_seq_show_raw(struct seq_file *f, unsigned char *p, int l)
+{
+	int i, j;
+
+	for (i = 0; ; i++) {
+		seq_printf(f, "%03x:", i);
+
+		for (j = 0; j < 16; j++) {
+			if (i * 16 + j >= l) {
+				seq_printf(f, "\n");
+				goto out;
+			}
+
+			seq_printf(f, " %02x", (unsigned char)p[i * 16 + j]);
+		}
+		seq_printf(f, "\n");
+	}
+out:
+	return (0);
+}
+
+static int
+kstat_seq_show_named(struct seq_file *f, kstat_named_t *knp)
+{
+	seq_printf(f, "%-31s %-4d ", knp->name, knp->data_type);
+
+	switch (knp->data_type) {
+		case KSTAT_DATA_CHAR:
+			knp->value.c[15] = '\0'; /* NULL terminate */
+			seq_printf(f, "%-16s", knp->value.c);
+			break;
+		/*
+		 * NOTE - We need to be more careful able what tokens are
+		 * used for each arch, for now this is correct for x86_64.
+		 */
+		case KSTAT_DATA_INT32:
+			seq_printf(f, "%d", knp->value.i32);
+			break;
+		case KSTAT_DATA_UINT32:
+			seq_printf(f, "%u", knp->value.ui32);
+			break;
+		case KSTAT_DATA_INT64:
+			seq_printf(f, "%lld", (signed long long)knp->value.i64);
+			break;
+		case KSTAT_DATA_UINT64:
+			seq_printf(f, "%llu",
+			    (unsigned long long)knp->value.ui64);
+			break;
+		case KSTAT_DATA_LONG:
+			seq_printf(f, "%ld", knp->value.l);
+			break;
+		case KSTAT_DATA_ULONG:
+			seq_printf(f, "%lu", knp->value.ul);
+			break;
+		case KSTAT_DATA_STRING:
+			KSTAT_NAMED_STR_PTR(knp)
+				[KSTAT_NAMED_STR_BUFLEN(knp)-1] = '\0';
+			seq_printf(f, "%s", KSTAT_NAMED_STR_PTR(knp));
+			break;
+		default:
+			PANIC("Undefined kstat data type %d\n", knp->data_type);
+	}
+
+	seq_printf(f, "\n");
+
+	return (0);
+}
+
+static int
+kstat_seq_show_intr(struct seq_file *f, kstat_intr_t *kip)
+{
+	seq_printf(f, "%-8u %-8u %-8u %-8u %-8u\n",
+	    kip->intrs[KSTAT_INTR_HARD],
+	    kip->intrs[KSTAT_INTR_SOFT],
+	    kip->intrs[KSTAT_INTR_WATCHDOG],
+	    kip->intrs[KSTAT_INTR_SPURIOUS],
+	    kip->intrs[KSTAT_INTR_MULTSVC]);
+
+	return (0);
+}
+
+static int
+kstat_seq_show_io(struct seq_file *f, kstat_io_t *kip)
+{
+	seq_printf(f,
+	    "%-8llu %-8llu %-8u %-8u %-8lld %-8lld "
+	    "%-8lld %-8lld %-8lld %-8lld %-8u %-8u\n",
+	    kip->nread, kip->nwritten,
+	    kip->reads, kip->writes,
+	    kip->wtime, kip->wlentime, kip->wlastupdate,
+	    kip->rtime, kip->rlentime, kip->rlastupdate,
+	    kip->wcnt,  kip->rcnt);
+
+	return (0);
+}
+
+static int
+kstat_seq_show_timer(struct seq_file *f, kstat_timer_t *ktp)
+{
+	seq_printf(f,
+	    "%-31s %-8llu %-8lld %-8lld %-8lld %-8lld %-8lld\n",
+	    ktp->name, ktp->num_events, ktp->elapsed_time,
+	    ktp->min_time, ktp->max_time,
+	    ktp->start_time, ktp->stop_time);
+
+	return (0);
+}
+
+static int
+kstat_seq_show(struct seq_file *f, void *p)
+{
+	kstat_t *ksp = (kstat_t *)f->private;
+	int rc = 0;
+
+	ASSERT(ksp->ks_magic == KS_MAGIC);
+
+	switch (ksp->ks_type) {
+		case KSTAT_TYPE_RAW:
+restart:
+			if (ksp->ks_raw_ops.data) {
+				rc = ksp->ks_raw_ops.data(
+				    ksp->ks_raw_buf, ksp->ks_raw_bufsize, p);
+				if (rc == ENOMEM && !kstat_resize_raw(ksp))
+					goto restart;
+				if (!rc)
+					seq_puts(f, ksp->ks_raw_buf);
+			} else {
+				ASSERT(ksp->ks_ndata == 1);
+				rc = kstat_seq_show_raw(f, ksp->ks_data,
+				    ksp->ks_data_size);
+			}
+			break;
+		case KSTAT_TYPE_NAMED:
+			rc = kstat_seq_show_named(f, (kstat_named_t *)p);
+			break;
+		case KSTAT_TYPE_INTR:
+			rc = kstat_seq_show_intr(f, (kstat_intr_t *)p);
+			break;
+		case KSTAT_TYPE_IO:
+			rc = kstat_seq_show_io(f, (kstat_io_t *)p);
+			break;
+		case KSTAT_TYPE_TIMER:
+			rc = kstat_seq_show_timer(f, (kstat_timer_t *)p);
+			break;
+		default:
+			PANIC("Undefined kstat type %d\n", ksp->ks_type);
+	}
+
+	return (-rc);
+}
+
+static int
+kstat_default_update(kstat_t *ksp, int rw)
+{
+	ASSERT(ksp != NULL);
+
+	if (rw == KSTAT_WRITE)
+		return (EACCES);
+
+	return (0);
+}
+
+static void *
+kstat_seq_data_addr(kstat_t *ksp, loff_t n)
+{
+	void *rc = NULL;
+
+	switch (ksp->ks_type) {
+		case KSTAT_TYPE_RAW:
+			if (ksp->ks_raw_ops.addr)
+				rc = ksp->ks_raw_ops.addr(ksp, n);
+			else
+				rc = ksp->ks_data;
+			break;
+		case KSTAT_TYPE_NAMED:
+			rc = ksp->ks_data + n * sizeof (kstat_named_t);
+			break;
+		case KSTAT_TYPE_INTR:
+			rc = ksp->ks_data + n * sizeof (kstat_intr_t);
+			break;
+		case KSTAT_TYPE_IO:
+			rc = ksp->ks_data + n * sizeof (kstat_io_t);
+			break;
+		case KSTAT_TYPE_TIMER:
+			rc = ksp->ks_data + n * sizeof (kstat_timer_t);
+			break;
+		default:
+			PANIC("Undefined kstat type %d\n", ksp->ks_type);
+	}
+
+	return (rc);
+}
+
+static void *
+kstat_seq_start(struct seq_file *f, loff_t *pos)
+{
+	loff_t n = *pos;
+	kstat_t *ksp = (kstat_t *)f->private;
+	ASSERT(ksp->ks_magic == KS_MAGIC);
+
+	mutex_enter(ksp->ks_lock);
+
+	if (ksp->ks_type == KSTAT_TYPE_RAW) {
+		ksp->ks_raw_bufsize = PAGE_SIZE;
+		ksp->ks_raw_buf = vmem_alloc(ksp->ks_raw_bufsize, KM_SLEEP);
+	}
+
+	/* Dynamically update kstat, on error existing kstats are used */
+	(void) ksp->ks_update(ksp, KSTAT_READ);
+
+	ksp->ks_snaptime = gethrtime();
+
+	if (!n && kstat_seq_show_headers(f))
+		return (NULL);
+
+	if (n >= ksp->ks_ndata)
+		return (NULL);
+
+	return (kstat_seq_data_addr(ksp, n));
+}
+
+static void *
+kstat_seq_next(struct seq_file *f, void *p, loff_t *pos)
+{
+	kstat_t *ksp = (kstat_t *)f->private;
+	ASSERT(ksp->ks_magic == KS_MAGIC);
+
+	++*pos;
+	if (*pos >= ksp->ks_ndata)
+		return (NULL);
+
+	return (kstat_seq_data_addr(ksp, *pos));
+}
+
+static void
+kstat_seq_stop(struct seq_file *f, void *v)
+{
+	kstat_t *ksp = (kstat_t *)f->private;
+	ASSERT(ksp->ks_magic == KS_MAGIC);
+
+	if (ksp->ks_type == KSTAT_TYPE_RAW)
+		vmem_free(ksp->ks_raw_buf, ksp->ks_raw_bufsize);
+
+	mutex_exit(ksp->ks_lock);
+}
+
+static struct seq_operations kstat_seq_ops = {
+	.show  = kstat_seq_show,
+	.start = kstat_seq_start,
+	.next  = kstat_seq_next,
+	.stop  = kstat_seq_stop,
+};
+
+static kstat_module_t *
+kstat_find_module(char *name)
+{
+	kstat_module_t *module;
+
+	list_for_each_entry(module, &kstat_module_list, ksm_module_list) {
+		if (strncmp(name, module->ksm_name, KSTAT_STRLEN) == 0)
+			return (module);
+	}
+
+	return (NULL);
+}
+
+static kstat_module_t *
+kstat_create_module(char *name)
+{
+	kstat_module_t *module;
+	struct proc_dir_entry *pde;
+
+	pde = proc_mkdir(name, proc_spl_kstat);
+	if (pde == NULL)
+		return (NULL);
+
+	module = kmem_alloc(sizeof (kstat_module_t), KM_SLEEP);
+	module->ksm_proc = pde;
+	strlcpy(module->ksm_name, name, KSTAT_STRLEN+1);
+	INIT_LIST_HEAD(&module->ksm_kstat_list);
+	list_add_tail(&module->ksm_module_list, &kstat_module_list);
+
+	return (module);
+
+}
+
+static void
+kstat_delete_module(kstat_module_t *module)
+{
+	ASSERT(list_empty(&module->ksm_kstat_list));
+	remove_proc_entry(module->ksm_name, proc_spl_kstat);
+	list_del(&module->ksm_module_list);
+	kmem_free(module, sizeof (kstat_module_t));
+}
+
+static int
+proc_kstat_open(struct inode *inode, struct file *filp)
+{
+	struct seq_file *f;
+	int rc;
+
+	rc = seq_open(filp, &kstat_seq_ops);
+	if (rc)
+		return (rc);
+
+	f = filp->private_data;
+	f->private = PDE_DATA(inode);
+
+	return (rc);
+}
+
+static ssize_t
+proc_kstat_write(struct file *filp, const char __user *buf, size_t len,
+    loff_t *ppos)
+{
+	struct seq_file *f = filp->private_data;
+	kstat_t *ksp = f->private;
+	int rc;
+
+	ASSERT(ksp->ks_magic == KS_MAGIC);
+
+	mutex_enter(ksp->ks_lock);
+	rc = ksp->ks_update(ksp, KSTAT_WRITE);
+	mutex_exit(ksp->ks_lock);
+
+	if (rc)
+		return (-rc);
+
+	*ppos += len;
+	return (len);
+}
+
+static struct file_operations proc_kstat_operations = {
+	.open		= proc_kstat_open,
+	.write		= proc_kstat_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+void
+__kstat_set_raw_ops(kstat_t *ksp,
+    int (*headers)(char *buf, size_t size),
+    int (*data)(char *buf, size_t size, void *data),
+    void *(*addr)(kstat_t *ksp, loff_t index))
+{
+	ksp->ks_raw_ops.headers = headers;
+	ksp->ks_raw_ops.data    = data;
+	ksp->ks_raw_ops.addr    = addr;
+}
+EXPORT_SYMBOL(__kstat_set_raw_ops);
+
+kstat_t *
+__kstat_create(const char *ks_module, int ks_instance, const char *ks_name,
+    const char *ks_class, uchar_t ks_type, uint_t ks_ndata,
+    uchar_t ks_flags)
+{
+	kstat_t *ksp;
+
+	ASSERT(ks_module);
+	ASSERT(ks_instance == 0);
+	ASSERT(ks_name);
+	ASSERT(!(ks_flags & KSTAT_FLAG_UNSUPPORTED));
+
+	if ((ks_type == KSTAT_TYPE_INTR) || (ks_type == KSTAT_TYPE_IO))
+		ASSERT(ks_ndata == 1);
+
+	ksp = kmem_zalloc(sizeof (*ksp), KM_SLEEP);
+	if (ksp == NULL)
+		return (ksp);
+
+	mutex_enter(&kstat_module_lock);
+	ksp->ks_kid = kstat_id;
+	kstat_id++;
+	mutex_exit(&kstat_module_lock);
+
+	ksp->ks_magic = KS_MAGIC;
+	mutex_init(&ksp->ks_private_lock, NULL, MUTEX_DEFAULT, NULL);
+	ksp->ks_lock = &ksp->ks_private_lock;
+	INIT_LIST_HEAD(&ksp->ks_list);
+
+	ksp->ks_crtime = gethrtime();
+	ksp->ks_snaptime = ksp->ks_crtime;
+	strncpy(ksp->ks_module, ks_module, KSTAT_STRLEN);
+	ksp->ks_instance = ks_instance;
+	strncpy(ksp->ks_name, ks_name, KSTAT_STRLEN);
+	strncpy(ksp->ks_class, ks_class, KSTAT_STRLEN);
+	ksp->ks_type = ks_type;
+	ksp->ks_flags = ks_flags;
+	ksp->ks_update = kstat_default_update;
+	ksp->ks_private = NULL;
+	ksp->ks_raw_ops.headers = NULL;
+	ksp->ks_raw_ops.data = NULL;
+	ksp->ks_raw_ops.addr = NULL;
+	ksp->ks_raw_buf = NULL;
+	ksp->ks_raw_bufsize = 0;
+
+	switch (ksp->ks_type) {
+		case KSTAT_TYPE_RAW:
+			ksp->ks_ndata = 1;
+			ksp->ks_data_size = ks_ndata;
+			break;
+		case KSTAT_TYPE_NAMED:
+			ksp->ks_ndata = ks_ndata;
+			ksp->ks_data_size = ks_ndata * sizeof (kstat_named_t);
+			break;
+		case KSTAT_TYPE_INTR:
+			ksp->ks_ndata = ks_ndata;
+			ksp->ks_data_size = ks_ndata * sizeof (kstat_intr_t);
+			break;
+		case KSTAT_TYPE_IO:
+			ksp->ks_ndata = ks_ndata;
+			ksp->ks_data_size = ks_ndata * sizeof (kstat_io_t);
+			break;
+		case KSTAT_TYPE_TIMER:
+			ksp->ks_ndata = ks_ndata;
+			ksp->ks_data_size = ks_ndata * sizeof (kstat_timer_t);
+			break;
+		default:
+			PANIC("Undefined kstat type %d\n", ksp->ks_type);
+	}
+
+	if (ksp->ks_flags & KSTAT_FLAG_VIRTUAL) {
+		ksp->ks_data = NULL;
+	} else {
+		ksp->ks_data = kmem_zalloc(ksp->ks_data_size, KM_SLEEP);
+		if (ksp->ks_data == NULL) {
+			kmem_free(ksp, sizeof (*ksp));
+			ksp = NULL;
+		}
+	}
+
+	return (ksp);
+}
+EXPORT_SYMBOL(__kstat_create);
+
+static int
+kstat_detect_collision(kstat_t *ksp)
+{
+	kstat_module_t *module;
+	kstat_t *tmp;
+	char *parent;
+	char *cp;
+
+	parent = kmem_asprintf("%s", ksp->ks_module);
+
+	if ((cp = strrchr(parent, '/')) == NULL) {
+		strfree(parent);
+		return (0);
+	}
+
+	cp[0] = '\0';
+	if ((module = kstat_find_module(parent)) != NULL) {
+		list_for_each_entry(tmp, &module->ksm_kstat_list, ks_list) {
+			if (strncmp(tmp->ks_name, cp+1, KSTAT_STRLEN) == 0) {
+				strfree(parent);
+				return (EEXIST);
+			}
+		}
+	}
+
+	strfree(parent);
+	return (0);
+}
+
+void
+__kstat_install(kstat_t *ksp)
+{
+	kstat_module_t *module;
+	kstat_t *tmp;
+
+	ASSERT(ksp);
+
+	mutex_enter(&kstat_module_lock);
+
+	module = kstat_find_module(ksp->ks_module);
+	if (module == NULL) {
+		if (kstat_detect_collision(ksp) != 0) {
+			cmn_err(CE_WARN, "kstat_create('%s', '%s'): namespace" \
+			    " collision", ksp->ks_module, ksp->ks_name);
+			goto out;
+		}
+		module = kstat_create_module(ksp->ks_module);
+		if (module == NULL)
+			goto out;
+	}
+
+	/*
+	 * Only one entry by this name per-module, on failure the module
+	 * shouldn't be deleted because we know it has at least one entry.
+	 */
+	list_for_each_entry(tmp, &module->ksm_kstat_list, ks_list) {
+		if (strncmp(tmp->ks_name, ksp->ks_name, KSTAT_STRLEN) == 0)
+			goto out;
+	}
+
+	list_add_tail(&ksp->ks_list, &module->ksm_kstat_list);
+
+	mutex_enter(ksp->ks_lock);
+	ksp->ks_owner = module;
+	ksp->ks_proc = proc_create_data(ksp->ks_name, 0644,
+	    module->ksm_proc, &proc_kstat_operations, (void *)ksp);
+	if (ksp->ks_proc == NULL) {
+		list_del_init(&ksp->ks_list);
+		if (list_empty(&module->ksm_kstat_list))
+			kstat_delete_module(module);
+	}
+	mutex_exit(ksp->ks_lock);
+out:
+	mutex_exit(&kstat_module_lock);
+}
+EXPORT_SYMBOL(__kstat_install);
+
+void
+__kstat_delete(kstat_t *ksp)
+{
+	kstat_module_t *module = ksp->ks_owner;
+
+	mutex_enter(&kstat_module_lock);
+	list_del_init(&ksp->ks_list);
+	mutex_exit(&kstat_module_lock);
+
+	if (ksp->ks_proc) {
+		remove_proc_entry(ksp->ks_name, module->ksm_proc);
+
+		/* Remove top level module directory if it's empty */
+		if (list_empty(&module->ksm_kstat_list))
+			kstat_delete_module(module);
+	}
+
+	if (!(ksp->ks_flags & KSTAT_FLAG_VIRTUAL))
+		kmem_free(ksp->ks_data, ksp->ks_data_size);
+
+	ksp->ks_lock = NULL;
+	mutex_destroy(&ksp->ks_private_lock);
+	kmem_free(ksp, sizeof (*ksp));
+}
+EXPORT_SYMBOL(__kstat_delete);
+
+int
+spl_kstat_init(void)
+{
+	mutex_init(&kstat_module_lock, NULL, MUTEX_DEFAULT, NULL);
+	INIT_LIST_HEAD(&kstat_module_list);
+	kstat_id = 0;
+	return (0);
+}
+
+void
+spl_kstat_fini(void)
+{
+	ASSERT(list_empty(&kstat_module_list));
+	mutex_destroy(&kstat_module_lock);
+}
diff --git a/module/spl/spl-mutex.c b/module/spl/spl-mutex.c
new file mode 100644
index 000000000..ba818862b
--- /dev/null
+++ b/module/spl/spl-mutex.c
@@ -0,0 +1,30 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Mutex Implementation.
+ */
+
+#include <sys/mutex.h>
+
+int spl_mutex_init(void) { return 0; }
+void spl_mutex_fini(void) { }
diff --git a/module/spl/spl-proc.c b/module/spl/spl-proc.c
new file mode 100644
index 000000000..9c52924a4
--- /dev/null
+++ b/module/spl/spl-proc.c
@@ -0,0 +1,782 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Proc Implementation.
+ */
+
+#include <sys/systeminfo.h>
+#include <sys/kstat.h>
+#include <sys/kmem.h>
+#include <sys/kmem_cache.h>
+#include <sys/vmem.h>
+#include <sys/taskq.h>
+#include <sys/proc.h>
+#include <linux/ctype.h>
+#include <linux/kmod.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/version.h>
+
+#if defined(CONSTIFY_PLUGIN) && LINUX_VERSION_CODE >= KERNEL_VERSION(3, 8, 0)
+typedef struct ctl_table __no_const spl_ctl_table;
+#else
+typedef struct ctl_table spl_ctl_table;
+#endif
+
+static unsigned long table_min = 0;
+static unsigned long table_max = ~0;
+
+static struct ctl_table_header *spl_header = NULL;
+static struct proc_dir_entry *proc_spl = NULL;
+static struct proc_dir_entry *proc_spl_kmem = NULL;
+static struct proc_dir_entry *proc_spl_kmem_slab = NULL;
+static struct proc_dir_entry *proc_spl_taskq_all = NULL;
+static struct proc_dir_entry *proc_spl_taskq = NULL;
+struct proc_dir_entry *proc_spl_kstat = NULL;
+
+static int
+proc_copyin_string(char *kbuffer, int kbuffer_size, const char *ubuffer,
+    int ubuffer_size)
+{
+	int size;
+
+	if (ubuffer_size > kbuffer_size)
+		return (-EOVERFLOW);
+
+	if (copy_from_user((void *)kbuffer, (void *)ubuffer, ubuffer_size))
+		return (-EFAULT);
+
+	/* strip trailing whitespace */
+	size = strnlen(kbuffer, ubuffer_size);
+	while (size-- >= 0)
+		if (!isspace(kbuffer[size]))
+			break;
+
+	/* empty string */
+	if (size < 0)
+		return (-EINVAL);
+
+	/* no space to terminate */
+	if (size == kbuffer_size)
+		return (-EOVERFLOW);
+
+	kbuffer[size + 1] = 0;
+	return (0);
+}
+
+static int
+proc_copyout_string(char *ubuffer, int ubuffer_size, const char *kbuffer,
+    char *append)
+{
+	/*
+	 * NB if 'append' != NULL, it's a single character to append to the
+	 * copied out string - usually "\n", for /proc entries and
+	 * (i.e. a terminating zero byte) for sysctl entries
+	 */
+	int size = MIN(strlen(kbuffer), ubuffer_size);
+
+	if (copy_to_user(ubuffer, kbuffer, size))
+		return (-EFAULT);
+
+	if (append != NULL && size < ubuffer_size) {
+		if (copy_to_user(ubuffer + size, append, 1))
+			return (-EFAULT);
+
+		size++;
+	}
+
+	return (size);
+}
+
+#ifdef DEBUG_KMEM
+static int
+proc_domemused(struct ctl_table *table, int write,
+    void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	int rc = 0;
+	unsigned long min = 0, max = ~0, val;
+	spl_ctl_table dummy = *table;
+
+	dummy.data = &val;
+	dummy.proc_handler = &proc_dointvec;
+	dummy.extra1 = &min;
+	dummy.extra2 = &max;
+
+	if (write) {
+		*ppos += *lenp;
+	} else {
+#ifdef HAVE_ATOMIC64_T
+		val = atomic64_read((atomic64_t *)table->data);
+#else
+		val = atomic_read((atomic_t *)table->data);
+#endif /* HAVE_ATOMIC64_T */
+		rc = proc_doulongvec_minmax(&dummy, write, buffer, lenp, ppos);
+	}
+
+	return (rc);
+}
+#endif /* DEBUG_KMEM */
+
+static int
+proc_doslab(struct ctl_table *table, int write,
+    void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	int rc = 0;
+	unsigned long min = 0, max = ~0, val = 0, mask;
+	spl_ctl_table dummy = *table;
+	spl_kmem_cache_t *skc;
+
+	dummy.data = &val;
+	dummy.proc_handler = &proc_dointvec;
+	dummy.extra1 = &min;
+	dummy.extra2 = &max;
+
+	if (write) {
+		*ppos += *lenp;
+	} else {
+		down_read(&spl_kmem_cache_sem);
+		mask = (unsigned long)table->data;
+
+		list_for_each_entry(skc, &spl_kmem_cache_list, skc_list) {
+
+			/* Only use slabs of the correct kmem/vmem type */
+			if (!(skc->skc_flags & mask))
+				continue;
+
+			/* Sum the specified field for selected slabs */
+			switch (mask & (KMC_TOTAL | KMC_ALLOC | KMC_MAX)) {
+			case KMC_TOTAL:
+				val += skc->skc_slab_size * skc->skc_slab_total;
+				break;
+			case KMC_ALLOC:
+				val += skc->skc_obj_size * skc->skc_obj_alloc;
+				break;
+			case KMC_MAX:
+				val += skc->skc_obj_size * skc->skc_obj_max;
+				break;
+			}
+		}
+
+		up_read(&spl_kmem_cache_sem);
+		rc = proc_doulongvec_minmax(&dummy, write, buffer, lenp, ppos);
+	}
+
+	return (rc);
+}
+
+static int
+proc_dohostid(struct ctl_table *table, int write,
+    void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	int len, rc = 0;
+	char *end, str[32];
+
+	if (write) {
+		/*
+		 * We can't use proc_doulongvec_minmax() in the write
+		 * case here because hostid while a hex value has no
+		 * leading 0x which confuses the helper function.
+		 */
+		rc = proc_copyin_string(str, sizeof (str), buffer, *lenp);
+		if (rc < 0)
+			return (rc);
+
+		spl_hostid = simple_strtoul(str, &end, 16);
+		if (str == end)
+			return (-EINVAL);
+
+	} else {
+		len = snprintf(str, sizeof (str), "%lx",
+		    (unsigned long) zone_get_hostid(NULL));
+		if (*ppos >= len)
+			rc = 0;
+		else
+			rc = proc_copyout_string(buffer,
+			    *lenp, str + *ppos, "\n");
+
+		if (rc >= 0) {
+			*lenp = rc;
+			*ppos += rc;
+		}
+	}
+
+	return (rc);
+}
+
+static void
+taskq_seq_show_headers(struct seq_file *f)
+{
+	seq_printf(f, "%-25s %5s %5s %5s %5s %5s %5s %12s %5s %10s\n",
+	    "taskq", "act", "nthr", "spwn", "maxt", "pri",
+	    "mina", "maxa", "cura", "flags");
+}
+
+/* indices into the lheads array below */
+#define	LHEAD_PEND	0
+#define	LHEAD_PRIO	1
+#define	LHEAD_DELAY	2
+#define	LHEAD_WAIT	3
+#define	LHEAD_ACTIVE	4
+#define	LHEAD_SIZE	5
+
+/* BEGIN CSTYLED */
+static unsigned int spl_max_show_tasks = 512;
+module_param(spl_max_show_tasks, uint, 0644);
+MODULE_PARM_DESC(spl_max_show_tasks, "Max number of tasks shown in taskq proc");
+/* END CSTYLED */
+
+static int
+taskq_seq_show_impl(struct seq_file *f, void *p, boolean_t allflag)
+{
+	taskq_t *tq = p;
+	taskq_thread_t *tqt;
+	spl_wait_queue_entry_t *wq;
+	struct task_struct *tsk;
+	taskq_ent_t *tqe;
+	char name[100];
+	struct list_head *lheads[LHEAD_SIZE], *lh;
+	static char *list_names[LHEAD_SIZE] =
+	    {"pend", "prio", "delay", "wait", "active" };
+	int i, j, have_lheads = 0;
+	unsigned long wflags, flags;
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	spin_lock_irqsave(&tq->tq_wait_waitq.lock, wflags);
+
+	/* get the various lists and check whether they're empty */
+	lheads[LHEAD_PEND] = &tq->tq_pend_list;
+	lheads[LHEAD_PRIO] = &tq->tq_prio_list;
+	lheads[LHEAD_DELAY] = &tq->tq_delay_list;
+#ifdef HAVE_WAIT_QUEUE_HEAD_ENTRY
+	lheads[LHEAD_WAIT] = &tq->tq_wait_waitq.head;
+#else
+	lheads[LHEAD_WAIT] = &tq->tq_wait_waitq.task_list;
+#endif
+	lheads[LHEAD_ACTIVE] = &tq->tq_active_list;
+
+	for (i = 0; i < LHEAD_SIZE; ++i) {
+		if (list_empty(lheads[i]))
+			lheads[i] = NULL;
+		else
+			++have_lheads;
+	}
+
+	/* early return in non-"all" mode if lists are all empty */
+	if (!allflag && !have_lheads) {
+		spin_unlock_irqrestore(&tq->tq_wait_waitq.lock, wflags);
+		spin_unlock_irqrestore(&tq->tq_lock, flags);
+		return (0);
+	}
+
+	/* unlock the waitq quickly */
+	if (!lheads[LHEAD_WAIT])
+		spin_unlock_irqrestore(&tq->tq_wait_waitq.lock, wflags);
+
+	/* show the base taskq contents */
+	snprintf(name, sizeof (name), "%s/%d", tq->tq_name, tq->tq_instance);
+	seq_printf(f, "%-25s ", name);
+	seq_printf(f, "%5d %5d %5d %5d %5d %5d %12d %5d %10x\n",
+	    tq->tq_nactive, tq->tq_nthreads, tq->tq_nspawn,
+	    tq->tq_maxthreads, tq->tq_pri, tq->tq_minalloc, tq->tq_maxalloc,
+	    tq->tq_nalloc, tq->tq_flags);
+
+	/* show the active list */
+	if (lheads[LHEAD_ACTIVE]) {
+		j = 0;
+		list_for_each_entry(tqt, &tq->tq_active_list, tqt_active_list) {
+			if (j == 0)
+				seq_printf(f, "\t%s:",
+				    list_names[LHEAD_ACTIVE]);
+			else if (j == 2) {
+				seq_printf(f, "\n\t       ");
+				j = 0;
+			}
+			seq_printf(f, " [%d]%pf(%ps)",
+			    tqt->tqt_thread->pid,
+			    tqt->tqt_task->tqent_func,
+			    tqt->tqt_task->tqent_arg);
+			++j;
+		}
+		seq_printf(f, "\n");
+	}
+
+	for (i = LHEAD_PEND; i <= LHEAD_WAIT; ++i)
+		if (lheads[i]) {
+			j = 0;
+			list_for_each(lh, lheads[i]) {
+				if (spl_max_show_tasks != 0 &&
+				    j >= spl_max_show_tasks) {
+					seq_printf(f, "\n\t(truncated)");
+					break;
+				}
+				/* show the wait waitq list */
+				if (i == LHEAD_WAIT) {
+#ifdef HAVE_WAIT_QUEUE_HEAD_ENTRY
+					wq = list_entry(lh,
+					    spl_wait_queue_entry_t, entry);
+#else
+					wq = list_entry(lh,
+					    spl_wait_queue_entry_t, task_list);
+#endif
+					if (j == 0)
+						seq_printf(f, "\t%s:",
+						    list_names[i]);
+					else if (j % 8 == 0)
+						seq_printf(f, "\n\t     ");
+
+					tsk = wq->private;
+					seq_printf(f, " %d", tsk->pid);
+				/* pend, prio and delay lists */
+				} else {
+					tqe = list_entry(lh, taskq_ent_t,
+					    tqent_list);
+					if (j == 0)
+						seq_printf(f, "\t%s:",
+						    list_names[i]);
+					else if (j % 2 == 0)
+						seq_printf(f, "\n\t     ");
+
+					seq_printf(f, " %pf(%ps)",
+					    tqe->tqent_func,
+					    tqe->tqent_arg);
+				}
+				++j;
+			}
+			seq_printf(f, "\n");
+		}
+	if (lheads[LHEAD_WAIT])
+		spin_unlock_irqrestore(&tq->tq_wait_waitq.lock, wflags);
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	return (0);
+}
+
+static int
+taskq_all_seq_show(struct seq_file *f, void *p)
+{
+	return (taskq_seq_show_impl(f, p, B_TRUE));
+}
+
+static int
+taskq_seq_show(struct seq_file *f, void *p)
+{
+	return (taskq_seq_show_impl(f, p, B_FALSE));
+}
+
+static void *
+taskq_seq_start(struct seq_file *f, loff_t *pos)
+{
+	struct list_head *p;
+	loff_t n = *pos;
+
+	down_read(&tq_list_sem);
+	if (!n)
+		taskq_seq_show_headers(f);
+
+	p = tq_list.next;
+	while (n--) {
+		p = p->next;
+		if (p == &tq_list)
+		return (NULL);
+	}
+
+	return (list_entry(p, taskq_t, tq_taskqs));
+}
+
+static void *
+taskq_seq_next(struct seq_file *f, void *p, loff_t *pos)
+{
+	taskq_t *tq = p;
+
+	++*pos;
+	return ((tq->tq_taskqs.next == &tq_list) ?
+	    NULL : list_entry(tq->tq_taskqs.next, taskq_t, tq_taskqs));
+}
+
+static void
+slab_seq_show_headers(struct seq_file *f)
+{
+	seq_printf(f,
+	    "--------------------- cache ----------"
+	    "---------------------------------------------  "
+	    "----- slab ------  "
+	    "---- object -----  "
+	    "--- emergency ---\n");
+	seq_printf(f,
+	    "name                                  "
+	    "  flags      size     alloc slabsize  objsize  "
+	    "total alloc   max  "
+	    "total alloc   max  "
+	    "dlock alloc   max\n");
+}
+
+static int
+slab_seq_show(struct seq_file *f, void *p)
+{
+	spl_kmem_cache_t *skc = p;
+
+	ASSERT(skc->skc_magic == SKC_MAGIC);
+
+	/*
+	 * Backed by Linux slab see /proc/slabinfo.
+	 */
+	if (skc->skc_flags & KMC_SLAB)
+		return (0);
+
+	spin_lock(&skc->skc_lock);
+	seq_printf(f, "%-36s  ", skc->skc_name);
+	seq_printf(f, "0x%05lx %9lu %9lu %8u %8u  "
+	    "%5lu %5lu %5lu  %5lu %5lu %5lu  %5lu %5lu %5lu\n",
+	    (long unsigned)skc->skc_flags,
+	    (long unsigned)(skc->skc_slab_size * skc->skc_slab_total),
+	    (long unsigned)(skc->skc_obj_size * skc->skc_obj_alloc),
+	    (unsigned)skc->skc_slab_size,
+	    (unsigned)skc->skc_obj_size,
+	    (long unsigned)skc->skc_slab_total,
+	    (long unsigned)skc->skc_slab_alloc,
+	    (long unsigned)skc->skc_slab_max,
+	    (long unsigned)skc->skc_obj_total,
+	    (long unsigned)skc->skc_obj_alloc,
+	    (long unsigned)skc->skc_obj_max,
+	    (long unsigned)skc->skc_obj_deadlock,
+	    (long unsigned)skc->skc_obj_emergency,
+	    (long unsigned)skc->skc_obj_emergency_max);
+
+	spin_unlock(&skc->skc_lock);
+
+	return (0);
+}
+
+static void *
+slab_seq_start(struct seq_file *f, loff_t *pos)
+{
+	struct list_head *p;
+	loff_t n = *pos;
+
+	down_read(&spl_kmem_cache_sem);
+	if (!n)
+		slab_seq_show_headers(f);
+
+	p = spl_kmem_cache_list.next;
+	while (n--) {
+		p = p->next;
+		if (p == &spl_kmem_cache_list)
+			return (NULL);
+	}
+
+	return (list_entry(p, spl_kmem_cache_t, skc_list));
+}
+
+static void *
+slab_seq_next(struct seq_file *f, void *p, loff_t *pos)
+{
+	spl_kmem_cache_t *skc = p;
+
+	++*pos;
+	return ((skc->skc_list.next == &spl_kmem_cache_list) ?
+	    NULL : list_entry(skc->skc_list.next, spl_kmem_cache_t, skc_list));
+}
+
+static void
+slab_seq_stop(struct seq_file *f, void *v)
+{
+	up_read(&spl_kmem_cache_sem);
+}
+
+static struct seq_operations slab_seq_ops = {
+	.show  = slab_seq_show,
+	.start = slab_seq_start,
+	.next  = slab_seq_next,
+	.stop  = slab_seq_stop,
+};
+
+static int
+proc_slab_open(struct inode *inode, struct file *filp)
+{
+	return (seq_open(filp, &slab_seq_ops));
+}
+
+static struct file_operations proc_slab_operations = {
+	.open	   = proc_slab_open,
+	.read	   = seq_read,
+	.llseek	 = seq_lseek,
+	.release	= seq_release,
+};
+
+static void
+taskq_seq_stop(struct seq_file *f, void *v)
+{
+	up_read(&tq_list_sem);
+}
+
+static struct seq_operations taskq_all_seq_ops = {
+	.show	= taskq_all_seq_show,
+	.start	= taskq_seq_start,
+	.next	= taskq_seq_next,
+	.stop	= taskq_seq_stop,
+};
+
+static struct seq_operations taskq_seq_ops = {
+	.show	= taskq_seq_show,
+	.start	= taskq_seq_start,
+	.next	= taskq_seq_next,
+	.stop	= taskq_seq_stop,
+};
+
+static int
+proc_taskq_all_open(struct inode *inode, struct file *filp)
+{
+	return (seq_open(filp, &taskq_all_seq_ops));
+}
+
+static int
+proc_taskq_open(struct inode *inode, struct file *filp)
+{
+	return (seq_open(filp, &taskq_seq_ops));
+}
+
+static struct file_operations proc_taskq_all_operations = {
+	.open		= proc_taskq_all_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static struct file_operations proc_taskq_operations = {
+	.open		= proc_taskq_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static struct ctl_table spl_kmem_table[] = {
+#ifdef DEBUG_KMEM
+	{
+		.procname	= "kmem_used",
+		.data		= &kmem_alloc_used,
+#ifdef HAVE_ATOMIC64_T
+		.maxlen		= sizeof (atomic64_t),
+#else
+		.maxlen		= sizeof (atomic_t),
+#endif /* HAVE_ATOMIC64_T */
+		.mode		= 0444,
+		.proc_handler	= &proc_domemused,
+	},
+	{
+		.procname	= "kmem_max",
+		.data		= &kmem_alloc_max,
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler	= &proc_doulongvec_minmax,
+	},
+#endif /* DEBUG_KMEM */
+	{
+		.procname	= "slab_kmem_total",
+		.data		= (void *)(KMC_KMEM | KMC_TOTAL),
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler = &proc_doslab,
+	},
+	{
+		.procname	= "slab_kmem_alloc",
+		.data		= (void *)(KMC_KMEM | KMC_ALLOC),
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler	= &proc_doslab,
+	},
+	{
+		.procname	= "slab_kmem_max",
+		.data		= (void *)(KMC_KMEM | KMC_MAX),
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler	= &proc_doslab,
+	},
+	{
+		.procname	= "slab_vmem_total",
+		.data		= (void *)(KMC_VMEM | KMC_TOTAL),
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler	= &proc_doslab,
+	},
+	{
+		.procname	= "slab_vmem_alloc",
+		.data		= (void *)(KMC_VMEM | KMC_ALLOC),
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler	= &proc_doslab,
+	},
+	{
+		.procname	= "slab_vmem_max",
+		.data		= (void *)(KMC_VMEM | KMC_MAX),
+		.maxlen		= sizeof (unsigned long),
+		.extra1		= &table_min,
+		.extra2		= &table_max,
+		.mode		= 0444,
+		.proc_handler	= &proc_doslab,
+	},
+	{},
+};
+
+static struct ctl_table spl_kstat_table[] = {
+	{},
+};
+
+static struct ctl_table spl_table[] = {
+	/*
+	 * NB No .strategy entries have been provided since
+	 * sysctl(8) prefers to go via /proc for portability.
+	 */
+	{
+		.procname	= "version",
+		.data		= spl_version,
+		.maxlen		= sizeof (spl_version),
+		.mode		= 0444,
+		.proc_handler	= &proc_dostring,
+	},
+	{
+		.procname	= "hostid",
+		.data		= &spl_hostid,
+		.maxlen		= sizeof (unsigned long),
+		.mode		= 0644,
+		.proc_handler	= &proc_dohostid,
+	},
+	{
+		.procname	= "kmem",
+		.mode		= 0555,
+		.child		= spl_kmem_table,
+	},
+	{
+		.procname	= "kstat",
+		.mode		= 0555,
+		.child		= spl_kstat_table,
+	},
+	{},
+};
+
+static struct ctl_table spl_dir[] = {
+	{
+		.procname	= "spl",
+		.mode		= 0555,
+		.child		= spl_table,
+	},
+	{}
+};
+
+static struct ctl_table spl_root[] = {
+	{
+#ifdef HAVE_CTL_NAME
+	.ctl_name = CTL_KERN,
+#endif
+	.procname = "kernel",
+	.mode = 0555,
+	.child = spl_dir,
+	},
+	{}
+};
+
+int
+spl_proc_init(void)
+{
+	int rc = 0;
+
+	spl_header = register_sysctl_table(spl_root);
+	if (spl_header == NULL)
+		return (-EUNATCH);
+
+	proc_spl = proc_mkdir("spl", NULL);
+	if (proc_spl == NULL) {
+		rc = -EUNATCH;
+		goto out;
+	}
+
+	proc_spl_taskq_all = proc_create_data("taskq-all", 0444, proc_spl,
+	    &proc_taskq_all_operations, NULL);
+	if (proc_spl_taskq_all == NULL) {
+		rc = -EUNATCH;
+		goto out;
+	}
+
+	proc_spl_taskq = proc_create_data("taskq", 0444, proc_spl,
+	    &proc_taskq_operations, NULL);
+	if (proc_spl_taskq == NULL) {
+		rc = -EUNATCH;
+		goto out;
+	}
+
+	proc_spl_kmem = proc_mkdir("kmem", proc_spl);
+	if (proc_spl_kmem == NULL) {
+		rc = -EUNATCH;
+		goto out;
+	}
+
+	proc_spl_kmem_slab = proc_create_data("slab", 0444, proc_spl_kmem,
+	    &proc_slab_operations, NULL);
+	if (proc_spl_kmem_slab == NULL) {
+		rc = -EUNATCH;
+		goto out;
+	}
+
+	proc_spl_kstat = proc_mkdir("kstat", proc_spl);
+	if (proc_spl_kstat == NULL) {
+		rc = -EUNATCH;
+		goto out;
+	}
+out:
+	if (rc) {
+		remove_proc_entry("kstat", proc_spl);
+		remove_proc_entry("slab", proc_spl_kmem);
+		remove_proc_entry("kmem", proc_spl);
+		remove_proc_entry("taskq-all", proc_spl);
+		remove_proc_entry("taskq", proc_spl);
+		remove_proc_entry("spl", NULL);
+		unregister_sysctl_table(spl_header);
+	}
+
+	return (rc);
+}
+
+void
+spl_proc_fini(void)
+{
+	remove_proc_entry("kstat", proc_spl);
+	remove_proc_entry("slab", proc_spl_kmem);
+	remove_proc_entry("kmem", proc_spl);
+	remove_proc_entry("taskq-all", proc_spl);
+	remove_proc_entry("taskq", proc_spl);
+	remove_proc_entry("spl", NULL);
+
+	ASSERT(spl_header != NULL);
+	unregister_sysctl_table(spl_header);
+}
diff --git a/module/spl/spl-rwlock.c b/module/spl/spl-rwlock.c
new file mode 100644
index 000000000..9a992cc3a
--- /dev/null
+++ b/module/spl/spl-rwlock.c
@@ -0,0 +1,114 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Reader/Writer Lock Implementation.
+ */
+
+#include <sys/rwlock.h>
+
+#if defined(CONFIG_PREEMPT_RT_FULL)
+
+#include <linux/rtmutex.h>
+#define	RT_MUTEX_OWNER_MASKALL	1UL
+
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+
+	ASSERT((struct task_struct *)
+	    ((unsigned long)rwsem->lock.owner & ~RT_MUTEX_OWNER_MASKALL) ==
+	    current);
+
+	/*
+	 * Under the realtime patch series, rwsem is implemented as a
+	 * single mutex held by readers and writers alike. However,
+	 * this implementation would prevent a thread from taking a
+	 * read lock twice, as the mutex would already be locked on
+	 * the second attempt. Therefore the implementation allows a
+	 * single thread to take a rwsem as read lock multiple times
+	 * tracking that nesting as read_depth counter.
+	 */
+	if (rwsem->read_depth <= 1) {
+		/*
+		 * In case, the current thread has not taken the lock
+		 * more than once as read lock, we can allow an
+		 * upgrade to a write lock. rwsem_rt.h implements
+		 * write locks as read_depth == 0.
+		 */
+		rwsem->read_depth = 0;
+		return (1);
+	}
+	return (0);
+}
+#elif defined(CONFIG_RWSEM_GENERIC_SPINLOCK)
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+	int ret = 0;
+	unsigned long flags;
+	spl_rwsem_lock_irqsave(&rwsem->wait_lock, flags);
+	if (RWSEM_COUNT(rwsem) == SPL_RWSEM_SINGLE_READER_VALUE &&
+	    list_empty(&rwsem->wait_list)) {
+		ret = 1;
+		RWSEM_COUNT(rwsem) = SPL_RWSEM_SINGLE_WRITER_VALUE;
+	}
+	spl_rwsem_unlock_irqrestore(&rwsem->wait_lock, flags);
+	return (ret);
+}
+#elif defined(HAVE_RWSEM_ATOMIC_LONG_COUNT)
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+	long val;
+	val = atomic_long_cmpxchg(&rwsem->count, SPL_RWSEM_SINGLE_READER_VALUE,
+	    SPL_RWSEM_SINGLE_WRITER_VALUE);
+	return (val == SPL_RWSEM_SINGLE_READER_VALUE);
+}
+#else
+static int
+__rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+	typeof(rwsem->count) val;
+	val = cmpxchg(&rwsem->count, SPL_RWSEM_SINGLE_READER_VALUE,
+	    SPL_RWSEM_SINGLE_WRITER_VALUE);
+	return (val == SPL_RWSEM_SINGLE_READER_VALUE);
+}
+#endif
+
+int
+rwsem_tryupgrade(struct rw_semaphore *rwsem)
+{
+	if (__rwsem_tryupgrade(rwsem)) {
+		rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+		rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+		rwsem->owner = current;
+#endif
+		return (1);
+	}
+	return (0);
+}
+EXPORT_SYMBOL(rwsem_tryupgrade);
+
+int spl_rw_init(void) { return 0; }
+void spl_rw_fini(void) { }
diff --git a/module/spl/spl-taskq.c b/module/spl/spl-taskq.c
new file mode 100644
index 000000000..2919a942a
--- /dev/null
+++ b/module/spl/spl-taskq.c
@@ -0,0 +1,1305 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Task Queue Implementation.
+ */
+
+#include <sys/taskq.h>
+#include <sys/kmem.h>
+#include <sys/tsd.h>
+
+int spl_taskq_thread_bind = 0;
+module_param(spl_taskq_thread_bind, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_bind, "Bind taskq thread to CPU by default");
+
+
+int spl_taskq_thread_dynamic = 1;
+module_param(spl_taskq_thread_dynamic, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_dynamic, "Allow dynamic taskq threads");
+
+int spl_taskq_thread_priority = 1;
+module_param(spl_taskq_thread_priority, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_priority,
+	"Allow non-default priority for taskq threads");
+
+int spl_taskq_thread_sequential = 4;
+module_param(spl_taskq_thread_sequential, int, 0644);
+MODULE_PARM_DESC(spl_taskq_thread_sequential,
+	"Create new taskq threads after N sequential tasks");
+
+/* Global system-wide dynamic task queue available for all consumers */
+taskq_t *system_taskq;
+EXPORT_SYMBOL(system_taskq);
+/* Global dynamic task queue for long delay */
+taskq_t *system_delay_taskq;
+EXPORT_SYMBOL(system_delay_taskq);
+
+/* Private dedicated taskq for creating new taskq threads on demand. */
+static taskq_t *dynamic_taskq;
+static taskq_thread_t *taskq_thread_create(taskq_t *);
+
+/* List of all taskqs */
+LIST_HEAD(tq_list);
+DECLARE_RWSEM(tq_list_sem);
+static uint_t taskq_tsd;
+
+static int
+task_km_flags(uint_t flags)
+{
+	if (flags & TQ_NOSLEEP)
+		return (KM_NOSLEEP);
+
+	if (flags & TQ_PUSHPAGE)
+		return (KM_PUSHPAGE);
+
+	return (KM_SLEEP);
+}
+
+/*
+ * taskq_find_by_name - Find the largest instance number of a named taskq.
+ */
+static int
+taskq_find_by_name(const char *name)
+{
+	struct list_head *tql;
+	taskq_t *tq;
+
+	list_for_each_prev(tql, &tq_list) {
+		tq = list_entry(tql, taskq_t, tq_taskqs);
+		if (strcmp(name, tq->tq_name) == 0)
+			return (tq->tq_instance);
+	}
+	return (-1);
+}
+
+/*
+ * NOTE: Must be called with tq->tq_lock held, returns a list_t which
+ * is not attached to the free, work, or pending taskq lists.
+ */
+static taskq_ent_t *
+task_alloc(taskq_t *tq, uint_t flags, unsigned long *irqflags)
+{
+	taskq_ent_t *t;
+	int count = 0;
+
+	ASSERT(tq);
+retry:
+	/* Acquire taskq_ent_t's from free list if available */
+	if (!list_empty(&tq->tq_free_list) && !(flags & TQ_NEW)) {
+		t = list_entry(tq->tq_free_list.next, taskq_ent_t, tqent_list);
+
+		ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+		ASSERT(!(t->tqent_flags & TQENT_FLAG_CANCEL));
+		ASSERT(!timer_pending(&t->tqent_timer));
+
+		list_del_init(&t->tqent_list);
+		return (t);
+	}
+
+	/* Free list is empty and memory allocations are prohibited */
+	if (flags & TQ_NOALLOC)
+		return (NULL);
+
+	/* Hit maximum taskq_ent_t pool size */
+	if (tq->tq_nalloc >= tq->tq_maxalloc) {
+		if (flags & TQ_NOSLEEP)
+			return (NULL);
+
+		/*
+		 * Sleep periodically polling the free list for an available
+		 * taskq_ent_t. Dispatching with TQ_SLEEP should always succeed
+		 * but we cannot block forever waiting for an taskq_ent_t to
+		 * show up in the free list, otherwise a deadlock can happen.
+		 *
+		 * Therefore, we need to allocate a new task even if the number
+		 * of allocated tasks is above tq->tq_maxalloc, but we still
+		 * end up delaying the task allocation by one second, thereby
+		 * throttling the task dispatch rate.
+		 */
+		spin_unlock_irqrestore(&tq->tq_lock, *irqflags);
+		schedule_timeout(HZ / 100);
+		spin_lock_irqsave_nested(&tq->tq_lock, *irqflags,
+		    tq->tq_lock_class);
+		if (count < 100) {
+			count++;
+			goto retry;
+		}
+	}
+
+	spin_unlock_irqrestore(&tq->tq_lock, *irqflags);
+	t = kmem_alloc(sizeof (taskq_ent_t), task_km_flags(flags));
+	spin_lock_irqsave_nested(&tq->tq_lock, *irqflags, tq->tq_lock_class);
+
+	if (t) {
+		taskq_init_ent(t);
+		tq->tq_nalloc++;
+	}
+
+	return (t);
+}
+
+/*
+ * NOTE: Must be called with tq->tq_lock held, expects the taskq_ent_t
+ * to already be removed from the free, work, or pending taskq lists.
+ */
+static void
+task_free(taskq_t *tq, taskq_ent_t *t)
+{
+	ASSERT(tq);
+	ASSERT(t);
+	ASSERT(list_empty(&t->tqent_list));
+	ASSERT(!timer_pending(&t->tqent_timer));
+
+	kmem_free(t, sizeof (taskq_ent_t));
+	tq->tq_nalloc--;
+}
+
+/*
+ * NOTE: Must be called with tq->tq_lock held, either destroys the
+ * taskq_ent_t if too many exist or moves it to the free list for later use.
+ */
+static void
+task_done(taskq_t *tq, taskq_ent_t *t)
+{
+	ASSERT(tq);
+	ASSERT(t);
+
+	/* Wake tasks blocked in taskq_wait_id() */
+	wake_up_all(&t->tqent_waitq);
+
+	list_del_init(&t->tqent_list);
+
+	if (tq->tq_nalloc <= tq->tq_minalloc) {
+		t->tqent_id = TASKQID_INVALID;
+		t->tqent_func = NULL;
+		t->tqent_arg = NULL;
+		t->tqent_flags = 0;
+
+		list_add_tail(&t->tqent_list, &tq->tq_free_list);
+	} else {
+		task_free(tq, t);
+	}
+}
+
+/*
+ * When a delayed task timer expires remove it from the delay list and
+ * add it to the priority list in order for immediate processing.
+ */
+static void
+task_expire_impl(taskq_ent_t *t)
+{
+	taskq_ent_t *w;
+	taskq_t *tq = t->tqent_taskq;
+	struct list_head *l;
+	unsigned long flags;
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+
+	if (t->tqent_flags & TQENT_FLAG_CANCEL) {
+		ASSERT(list_empty(&t->tqent_list));
+		spin_unlock_irqrestore(&tq->tq_lock, flags);
+		return;
+	}
+
+	t->tqent_birth = jiffies;
+	/*
+	 * The priority list must be maintained in strict task id order
+	 * from lowest to highest for lowest_id to be easily calculable.
+	 */
+	list_del(&t->tqent_list);
+	list_for_each_prev(l, &tq->tq_prio_list) {
+		w = list_entry(l, taskq_ent_t, tqent_list);
+		if (w->tqent_id < t->tqent_id) {
+			list_add(&t->tqent_list, l);
+			break;
+		}
+	}
+	if (l == &tq->tq_prio_list)
+		list_add(&t->tqent_list, &tq->tq_prio_list);
+
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	wake_up(&tq->tq_work_waitq);
+}
+
+#ifdef HAVE_KERNEL_TIMER_FUNCTION_TIMER_LIST
+static void
+task_expire(struct timer_list *tl)
+{
+	taskq_ent_t *t = from_timer(t, tl, tqent_timer);
+	task_expire_impl(t);
+}
+#else
+static void
+task_expire(unsigned long data)
+{
+	task_expire_impl((taskq_ent_t *)data);
+}
+#endif
+
+/*
+ * Returns the lowest incomplete taskqid_t.  The taskqid_t may
+ * be queued on the pending list, on the priority list, on the
+ * delay list, or on the work list currently being handled, but
+ * it is not 100% complete yet.
+ */
+static taskqid_t
+taskq_lowest_id(taskq_t *tq)
+{
+	taskqid_t lowest_id = tq->tq_next_id;
+	taskq_ent_t *t;
+	taskq_thread_t *tqt;
+
+	ASSERT(tq);
+
+	if (!list_empty(&tq->tq_pend_list)) {
+		t = list_entry(tq->tq_pend_list.next, taskq_ent_t, tqent_list);
+		lowest_id = MIN(lowest_id, t->tqent_id);
+	}
+
+	if (!list_empty(&tq->tq_prio_list)) {
+		t = list_entry(tq->tq_prio_list.next, taskq_ent_t, tqent_list);
+		lowest_id = MIN(lowest_id, t->tqent_id);
+	}
+
+	if (!list_empty(&tq->tq_delay_list)) {
+		t = list_entry(tq->tq_delay_list.next, taskq_ent_t, tqent_list);
+		lowest_id = MIN(lowest_id, t->tqent_id);
+	}
+
+	if (!list_empty(&tq->tq_active_list)) {
+		tqt = list_entry(tq->tq_active_list.next, taskq_thread_t,
+		    tqt_active_list);
+		ASSERT(tqt->tqt_id != TASKQID_INVALID);
+		lowest_id = MIN(lowest_id, tqt->tqt_id);
+	}
+
+	return (lowest_id);
+}
+
+/*
+ * Insert a task into a list keeping the list sorted by increasing taskqid.
+ */
+static void
+taskq_insert_in_order(taskq_t *tq, taskq_thread_t *tqt)
+{
+	taskq_thread_t *w;
+	struct list_head *l;
+
+	ASSERT(tq);
+	ASSERT(tqt);
+
+	list_for_each_prev(l, &tq->tq_active_list) {
+		w = list_entry(l, taskq_thread_t, tqt_active_list);
+		if (w->tqt_id < tqt->tqt_id) {
+			list_add(&tqt->tqt_active_list, l);
+			break;
+		}
+	}
+	if (l == &tq->tq_active_list)
+		list_add(&tqt->tqt_active_list, &tq->tq_active_list);
+}
+
+/*
+ * Find and return a task from the given list if it exists.  The list
+ * must be in lowest to highest task id order.
+ */
+static taskq_ent_t *
+taskq_find_list(taskq_t *tq, struct list_head *lh, taskqid_t id)
+{
+	struct list_head *l;
+	taskq_ent_t *t;
+
+	list_for_each(l, lh) {
+		t = list_entry(l, taskq_ent_t, tqent_list);
+
+		if (t->tqent_id == id)
+			return (t);
+
+		if (t->tqent_id > id)
+			break;
+	}
+
+	return (NULL);
+}
+
+/*
+ * Find an already dispatched task given the task id regardless of what
+ * state it is in.  If a task is still pending it will be returned.
+ * If a task is executing, then -EBUSY will be returned instead.
+ * If the task has already been run then NULL is returned.
+ */
+static taskq_ent_t *
+taskq_find(taskq_t *tq, taskqid_t id)
+{
+	taskq_thread_t *tqt;
+	struct list_head *l;
+	taskq_ent_t *t;
+
+	t = taskq_find_list(tq, &tq->tq_delay_list, id);
+	if (t)
+		return (t);
+
+	t = taskq_find_list(tq, &tq->tq_prio_list, id);
+	if (t)
+		return (t);
+
+	t = taskq_find_list(tq, &tq->tq_pend_list, id);
+	if (t)
+		return (t);
+
+	list_for_each(l, &tq->tq_active_list) {
+		tqt = list_entry(l, taskq_thread_t, tqt_active_list);
+		if (tqt->tqt_id == id) {
+			/*
+			 * Instead of returning tqt_task, we just return a non
+			 * NULL value to prevent misuse, since tqt_task only
+			 * has two valid fields.
+			 */
+			return (ERR_PTR(-EBUSY));
+		}
+	}
+
+	return (NULL);
+}
+
+/*
+ * Theory for the taskq_wait_id(), taskq_wait_outstanding(), and
+ * taskq_wait() functions below.
+ *
+ * Taskq waiting is accomplished by tracking the lowest outstanding task
+ * id and the next available task id.  As tasks are dispatched they are
+ * added to the tail of the pending, priority, or delay lists.  As worker
+ * threads become available the tasks are removed from the heads of these
+ * lists and linked to the worker threads.  This ensures the lists are
+ * kept sorted by lowest to highest task id.
+ *
+ * Therefore the lowest outstanding task id can be quickly determined by
+ * checking the head item from all of these lists.  This value is stored
+ * with the taskq as the lowest id.  It only needs to be recalculated when
+ * either the task with the current lowest id completes or is canceled.
+ *
+ * By blocking until the lowest task id exceeds the passed task id the
+ * taskq_wait_outstanding() function can be easily implemented.  Similarly,
+ * by blocking until the lowest task id matches the next task id taskq_wait()
+ * can be implemented.
+ *
+ * Callers should be aware that when there are multiple worked threads it
+ * is possible for larger task ids to complete before smaller ones.  Also
+ * when the taskq contains delay tasks with small task ids callers may
+ * block for a considerable length of time waiting for them to expire and
+ * execute.
+ */
+static int
+taskq_wait_id_check(taskq_t *tq, taskqid_t id)
+{
+	int rc;
+	unsigned long flags;
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	rc = (taskq_find(tq, id) == NULL);
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	return (rc);
+}
+
+/*
+ * The taskq_wait_id() function blocks until the passed task id completes.
+ * This does not guarantee that all lower task ids have completed.
+ */
+void
+taskq_wait_id(taskq_t *tq, taskqid_t id)
+{
+	wait_event(tq->tq_wait_waitq, taskq_wait_id_check(tq, id));
+}
+EXPORT_SYMBOL(taskq_wait_id);
+
+static int
+taskq_wait_outstanding_check(taskq_t *tq, taskqid_t id)
+{
+	int rc;
+	unsigned long flags;
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	rc = (id < tq->tq_lowest_id);
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	return (rc);
+}
+
+/*
+ * The taskq_wait_outstanding() function will block until all tasks with a
+ * lower taskqid than the passed 'id' have been completed.  Note that all
+ * task id's are assigned monotonically at dispatch time.  Zero may be
+ * passed for the id to indicate all tasks dispatch up to this point,
+ * but not after, should be waited for.
+ */
+void
+taskq_wait_outstanding(taskq_t *tq, taskqid_t id)
+{
+	id = id ? id : tq->tq_next_id - 1;
+	wait_event(tq->tq_wait_waitq, taskq_wait_outstanding_check(tq, id));
+}
+EXPORT_SYMBOL(taskq_wait_outstanding);
+
+static int
+taskq_wait_check(taskq_t *tq)
+{
+	int rc;
+	unsigned long flags;
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	rc = (tq->tq_lowest_id == tq->tq_next_id);
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	return (rc);
+}
+
+/*
+ * The taskq_wait() function will block until the taskq is empty.
+ * This means that if a taskq re-dispatches work to itself taskq_wait()
+ * callers will block indefinitely.
+ */
+void
+taskq_wait(taskq_t *tq)
+{
+	wait_event(tq->tq_wait_waitq, taskq_wait_check(tq));
+}
+EXPORT_SYMBOL(taskq_wait);
+
+int
+taskq_member(taskq_t *tq, kthread_t *t)
+{
+	return (tq == (taskq_t *)tsd_get_by_thread(taskq_tsd, t));
+}
+EXPORT_SYMBOL(taskq_member);
+
+/*
+ * Cancel an already dispatched task given the task id.  Still pending tasks
+ * will be immediately canceled, and if the task is active the function will
+ * block until it completes.  Preallocated tasks which are canceled must be
+ * freed by the caller.
+ */
+int
+taskq_cancel_id(taskq_t *tq, taskqid_t id)
+{
+	taskq_ent_t *t;
+	int rc = ENOENT;
+	unsigned long flags;
+
+	ASSERT(tq);
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	t = taskq_find(tq, id);
+	if (t && t != ERR_PTR(-EBUSY)) {
+		list_del_init(&t->tqent_list);
+		t->tqent_flags |= TQENT_FLAG_CANCEL;
+
+		/*
+		 * When canceling the lowest outstanding task id we
+		 * must recalculate the new lowest outstanding id.
+		 */
+		if (tq->tq_lowest_id == t->tqent_id) {
+			tq->tq_lowest_id = taskq_lowest_id(tq);
+			ASSERT3S(tq->tq_lowest_id, >, t->tqent_id);
+		}
+
+		/*
+		 * The task_expire() function takes the tq->tq_lock so drop
+		 * drop the lock before synchronously cancelling the timer.
+		 */
+		if (timer_pending(&t->tqent_timer)) {
+			spin_unlock_irqrestore(&tq->tq_lock, flags);
+			del_timer_sync(&t->tqent_timer);
+			spin_lock_irqsave_nested(&tq->tq_lock, flags,
+			    tq->tq_lock_class);
+		}
+
+		if (!(t->tqent_flags & TQENT_FLAG_PREALLOC))
+			task_done(tq, t);
+
+		rc = 0;
+	}
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	if (t == ERR_PTR(-EBUSY)) {
+		taskq_wait_id(tq, id);
+		rc = EBUSY;
+	}
+
+	return (rc);
+}
+EXPORT_SYMBOL(taskq_cancel_id);
+
+static int taskq_thread_spawn(taskq_t *tq);
+
+taskqid_t
+taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
+{
+	taskq_ent_t *t;
+	taskqid_t rc = TASKQID_INVALID;
+	unsigned long irqflags;
+
+	ASSERT(tq);
+	ASSERT(func);
+
+	spin_lock_irqsave_nested(&tq->tq_lock, irqflags, tq->tq_lock_class);
+
+	/* Taskq being destroyed and all tasks drained */
+	if (!(tq->tq_flags & TASKQ_ACTIVE))
+		goto out;
+
+	/* Do not queue the task unless there is idle thread for it */
+	ASSERT(tq->tq_nactive <= tq->tq_nthreads);
+	if ((flags & TQ_NOQUEUE) && (tq->tq_nactive == tq->tq_nthreads)) {
+		/* Dynamic taskq may be able to spawn another thread */
+		if (!(tq->tq_flags & TASKQ_DYNAMIC) ||
+		    taskq_thread_spawn(tq) == 0)
+			goto out;
+	}
+
+	if ((t = task_alloc(tq, flags, &irqflags)) == NULL)
+		goto out;
+
+	spin_lock(&t->tqent_lock);
+
+	/* Queue to the front of the list to enforce TQ_NOQUEUE semantics */
+	if (flags & TQ_NOQUEUE)
+		list_add(&t->tqent_list, &tq->tq_prio_list);
+	/* Queue to the priority list instead of the pending list */
+	else if (flags & TQ_FRONT)
+		list_add_tail(&t->tqent_list, &tq->tq_prio_list);
+	else
+		list_add_tail(&t->tqent_list, &tq->tq_pend_list);
+
+	t->tqent_id = rc = tq->tq_next_id;
+	tq->tq_next_id++;
+	t->tqent_func = func;
+	t->tqent_arg = arg;
+	t->tqent_taskq = tq;
+#ifndef HAVE_KERNEL_TIMER_FUNCTION_TIMER_LIST
+	t->tqent_timer.data = 0;
+#endif
+	t->tqent_timer.function = NULL;
+	t->tqent_timer.expires = 0;
+	t->tqent_birth = jiffies;
+
+	ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+
+	spin_unlock(&t->tqent_lock);
+
+	wake_up(&tq->tq_work_waitq);
+out:
+	/* Spawn additional taskq threads if required. */
+	if (!(flags & TQ_NOQUEUE) && tq->tq_nactive == tq->tq_nthreads)
+		(void) taskq_thread_spawn(tq);
+
+	spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+	return (rc);
+}
+EXPORT_SYMBOL(taskq_dispatch);
+
+taskqid_t
+taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
+    uint_t flags, clock_t expire_time)
+{
+	taskqid_t rc = TASKQID_INVALID;
+	taskq_ent_t *t;
+	unsigned long irqflags;
+
+	ASSERT(tq);
+	ASSERT(func);
+
+	spin_lock_irqsave_nested(&tq->tq_lock, irqflags, tq->tq_lock_class);
+
+	/* Taskq being destroyed and all tasks drained */
+	if (!(tq->tq_flags & TASKQ_ACTIVE))
+		goto out;
+
+	if ((t = task_alloc(tq, flags, &irqflags)) == NULL)
+		goto out;
+
+	spin_lock(&t->tqent_lock);
+
+	/* Queue to the delay list for subsequent execution */
+	list_add_tail(&t->tqent_list, &tq->tq_delay_list);
+
+	t->tqent_id = rc = tq->tq_next_id;
+	tq->tq_next_id++;
+	t->tqent_func = func;
+	t->tqent_arg = arg;
+	t->tqent_taskq = tq;
+#ifndef HAVE_KERNEL_TIMER_FUNCTION_TIMER_LIST
+	t->tqent_timer.data = (unsigned long)t;
+#endif
+	t->tqent_timer.function = task_expire;
+	t->tqent_timer.expires = (unsigned long)expire_time;
+	add_timer(&t->tqent_timer);
+
+	ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+
+	spin_unlock(&t->tqent_lock);
+out:
+	/* Spawn additional taskq threads if required. */
+	if (tq->tq_nactive == tq->tq_nthreads)
+		(void) taskq_thread_spawn(tq);
+	spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+	return (rc);
+}
+EXPORT_SYMBOL(taskq_dispatch_delay);
+
+void
+taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
+    taskq_ent_t *t)
+{
+	unsigned long irqflags;
+	ASSERT(tq);
+	ASSERT(func);
+
+	spin_lock_irqsave_nested(&tq->tq_lock, irqflags,
+	    tq->tq_lock_class);
+
+	/* Taskq being destroyed and all tasks drained */
+	if (!(tq->tq_flags & TASKQ_ACTIVE)) {
+		t->tqent_id = TASKQID_INVALID;
+		goto out;
+	}
+
+	if ((flags & TQ_NOQUEUE) && (tq->tq_nactive == tq->tq_nthreads)) {
+		/* Dynamic taskq may be able to spawn another thread */
+		if (!(tq->tq_flags & TASKQ_DYNAMIC) ||
+		    taskq_thread_spawn(tq) == 0)
+			goto out2;
+		flags |= TQ_FRONT;
+	}
+
+	spin_lock(&t->tqent_lock);
+
+	/*
+	 * Make sure the entry is not on some other taskq; it is important to
+	 * ASSERT() under lock
+	 */
+	ASSERT(taskq_empty_ent(t));
+
+	/*
+	 * Mark it as a prealloc'd task.  This is important
+	 * to ensure that we don't free it later.
+	 */
+	t->tqent_flags |= TQENT_FLAG_PREALLOC;
+
+	/* Queue to the priority list instead of the pending list */
+	if (flags & TQ_FRONT)
+		list_add_tail(&t->tqent_list, &tq->tq_prio_list);
+	else
+		list_add_tail(&t->tqent_list, &tq->tq_pend_list);
+
+	t->tqent_id = tq->tq_next_id;
+	tq->tq_next_id++;
+	t->tqent_func = func;
+	t->tqent_arg = arg;
+	t->tqent_taskq = tq;
+	t->tqent_birth = jiffies;
+
+	spin_unlock(&t->tqent_lock);
+
+	wake_up(&tq->tq_work_waitq);
+out:
+	/* Spawn additional taskq threads if required. */
+	if (tq->tq_nactive == tq->tq_nthreads)
+		(void) taskq_thread_spawn(tq);
+out2:
+	spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+}
+EXPORT_SYMBOL(taskq_dispatch_ent);
+
+int
+taskq_empty_ent(taskq_ent_t *t)
+{
+	return (list_empty(&t->tqent_list));
+}
+EXPORT_SYMBOL(taskq_empty_ent);
+
+void
+taskq_init_ent(taskq_ent_t *t)
+{
+	spin_lock_init(&t->tqent_lock);
+	init_waitqueue_head(&t->tqent_waitq);
+#ifdef HAVE_KERNEL_TIMER_FUNCTION_TIMER_LIST
+	timer_setup(&t->tqent_timer, NULL, 0);
+#else
+	init_timer(&t->tqent_timer);
+#endif
+	INIT_LIST_HEAD(&t->tqent_list);
+	t->tqent_id = 0;
+	t->tqent_func = NULL;
+	t->tqent_arg = NULL;
+	t->tqent_flags = 0;
+	t->tqent_taskq = NULL;
+}
+EXPORT_SYMBOL(taskq_init_ent);
+
+/*
+ * Return the next pending task, preference is given to tasks on the
+ * priority list which were dispatched with TQ_FRONT.
+ */
+static taskq_ent_t *
+taskq_next_ent(taskq_t *tq)
+{
+	struct list_head *list;
+
+	if (!list_empty(&tq->tq_prio_list))
+		list = &tq->tq_prio_list;
+	else if (!list_empty(&tq->tq_pend_list))
+		list = &tq->tq_pend_list;
+	else
+		return (NULL);
+
+	return (list_entry(list->next, taskq_ent_t, tqent_list));
+}
+
+/*
+ * Spawns a new thread for the specified taskq.
+ */
+static void
+taskq_thread_spawn_task(void *arg)
+{
+	taskq_t *tq = (taskq_t *)arg;
+	unsigned long flags;
+
+	if (taskq_thread_create(tq) == NULL) {
+		/* restore spawning count if failed */
+		spin_lock_irqsave_nested(&tq->tq_lock, flags,
+		    tq->tq_lock_class);
+		tq->tq_nspawn--;
+		spin_unlock_irqrestore(&tq->tq_lock, flags);
+	}
+}
+
+/*
+ * Spawn addition threads for dynamic taskqs (TASKQ_DYNAMIC) the current
+ * number of threads is insufficient to handle the pending tasks.  These
+ * new threads must be created by the dedicated dynamic_taskq to avoid
+ * deadlocks between thread creation and memory reclaim.  The system_taskq
+ * which is also a dynamic taskq cannot be safely used for this.
+ */
+static int
+taskq_thread_spawn(taskq_t *tq)
+{
+	int spawning = 0;
+
+	if (!(tq->tq_flags & TASKQ_DYNAMIC))
+		return (0);
+
+	if ((tq->tq_nthreads + tq->tq_nspawn < tq->tq_maxthreads) &&
+	    (tq->tq_flags & TASKQ_ACTIVE)) {
+		spawning = (++tq->tq_nspawn);
+		taskq_dispatch(dynamic_taskq, taskq_thread_spawn_task,
+		    tq, TQ_NOSLEEP);
+	}
+
+	return (spawning);
+}
+
+/*
+ * Threads in a dynamic taskq should only exit once it has been completely
+ * drained and no other threads are actively servicing tasks.  This prevents
+ * threads from being created and destroyed more than is required.
+ *
+ * The first thread is the thread list is treated as the primary thread.
+ * There is nothing special about the primary thread but in order to avoid
+ * all the taskq pids from changing we opt to make it long running.
+ */
+static int
+taskq_thread_should_stop(taskq_t *tq, taskq_thread_t *tqt)
+{
+	if (!(tq->tq_flags & TASKQ_DYNAMIC))
+		return (0);
+
+	if (list_first_entry(&(tq->tq_thread_list), taskq_thread_t,
+	    tqt_thread_list) == tqt)
+		return (0);
+
+	return
+	    ((tq->tq_nspawn == 0) &&	/* No threads are being spawned */
+	    (tq->tq_nactive == 0) &&	/* No threads are handling tasks */
+	    (tq->tq_nthreads > 1) &&	/* More than 1 thread is running */
+	    (!taskq_next_ent(tq)) &&	/* There are no pending tasks */
+	    (spl_taskq_thread_dynamic)); /* Dynamic taskqs are allowed */
+}
+
+static int
+taskq_thread(void *args)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	sigset_t blocked;
+	taskq_thread_t *tqt = args;
+	taskq_t *tq;
+	taskq_ent_t *t;
+	int seq_tasks = 0;
+	unsigned long flags;
+	taskq_ent_t dup_task = {};
+
+	ASSERT(tqt);
+	ASSERT(tqt->tqt_tq);
+	tq = tqt->tqt_tq;
+	current->flags |= PF_NOFREEZE;
+
+	(void) spl_fstrans_mark();
+
+	sigfillset(&blocked);
+	sigprocmask(SIG_BLOCK, &blocked, NULL);
+	flush_signals(current);
+
+	tsd_set(taskq_tsd, tq);
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	/*
+	 * If we are dynamically spawned, decrease spawning count. Note that
+	 * we could be created during taskq_create, in which case we shouldn't
+	 * do the decrement. But it's fine because taskq_create will reset
+	 * tq_nspawn later.
+	 */
+	if (tq->tq_flags & TASKQ_DYNAMIC)
+		tq->tq_nspawn--;
+
+	/* Immediately exit if more threads than allowed were created. */
+	if (tq->tq_nthreads >= tq->tq_maxthreads)
+		goto error;
+
+	tq->tq_nthreads++;
+	list_add_tail(&tqt->tqt_thread_list, &tq->tq_thread_list);
+	wake_up(&tq->tq_wait_waitq);
+	set_current_state(TASK_INTERRUPTIBLE);
+
+	while (!kthread_should_stop()) {
+
+		if (list_empty(&tq->tq_pend_list) &&
+		    list_empty(&tq->tq_prio_list)) {
+
+			if (taskq_thread_should_stop(tq, tqt)) {
+				wake_up_all(&tq->tq_wait_waitq);
+				break;
+			}
+
+			add_wait_queue_exclusive(&tq->tq_work_waitq, &wait);
+			spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+			schedule();
+			seq_tasks = 0;
+
+			spin_lock_irqsave_nested(&tq->tq_lock, flags,
+			    tq->tq_lock_class);
+			remove_wait_queue(&tq->tq_work_waitq, &wait);
+		} else {
+			__set_current_state(TASK_RUNNING);
+		}
+
+		if ((t = taskq_next_ent(tq)) != NULL) {
+			list_del_init(&t->tqent_list);
+
+			/*
+			 * A TQENT_FLAG_PREALLOC task may be reused or freed
+			 * during the task function call. Store tqent_id and
+			 * tqent_flags here.
+			 *
+			 * Also use an on stack taskq_ent_t for tqt_task
+			 * assignment in this case. We only populate the two
+			 * fields used by the only user in taskq proc file.
+			 */
+			tqt->tqt_id = t->tqent_id;
+			tqt->tqt_flags = t->tqent_flags;
+
+			if (t->tqent_flags & TQENT_FLAG_PREALLOC) {
+				dup_task.tqent_func = t->tqent_func;
+				dup_task.tqent_arg = t->tqent_arg;
+				t = &dup_task;
+			}
+			tqt->tqt_task = t;
+
+			taskq_insert_in_order(tq, tqt);
+			tq->tq_nactive++;
+			spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+			/* Perform the requested task */
+			t->tqent_func(t->tqent_arg);
+
+			spin_lock_irqsave_nested(&tq->tq_lock, flags,
+			    tq->tq_lock_class);
+			tq->tq_nactive--;
+			list_del_init(&tqt->tqt_active_list);
+			tqt->tqt_task = NULL;
+
+			/* For prealloc'd tasks, we don't free anything. */
+			if (!(tqt->tqt_flags & TQENT_FLAG_PREALLOC))
+				task_done(tq, t);
+
+			/*
+			 * When the current lowest outstanding taskqid is
+			 * done calculate the new lowest outstanding id
+			 */
+			if (tq->tq_lowest_id == tqt->tqt_id) {
+				tq->tq_lowest_id = taskq_lowest_id(tq);
+				ASSERT3S(tq->tq_lowest_id, >, tqt->tqt_id);
+			}
+
+			/* Spawn additional taskq threads if required. */
+			if ((++seq_tasks) > spl_taskq_thread_sequential &&
+			    taskq_thread_spawn(tq))
+				seq_tasks = 0;
+
+			tqt->tqt_id = TASKQID_INVALID;
+			tqt->tqt_flags = 0;
+			wake_up_all(&tq->tq_wait_waitq);
+		} else {
+			if (taskq_thread_should_stop(tq, tqt))
+				break;
+		}
+
+		set_current_state(TASK_INTERRUPTIBLE);
+
+	}
+
+	__set_current_state(TASK_RUNNING);
+	tq->tq_nthreads--;
+	list_del_init(&tqt->tqt_thread_list);
+error:
+	kmem_free(tqt, sizeof (taskq_thread_t));
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	tsd_set(taskq_tsd, NULL);
+
+	return (0);
+}
+
+static taskq_thread_t *
+taskq_thread_create(taskq_t *tq)
+{
+	static int last_used_cpu = 0;
+	taskq_thread_t *tqt;
+
+	tqt = kmem_alloc(sizeof (*tqt), KM_PUSHPAGE);
+	INIT_LIST_HEAD(&tqt->tqt_thread_list);
+	INIT_LIST_HEAD(&tqt->tqt_active_list);
+	tqt->tqt_tq = tq;
+	tqt->tqt_id = TASKQID_INVALID;
+
+	tqt->tqt_thread = spl_kthread_create(taskq_thread, tqt,
+	    "%s", tq->tq_name);
+	if (tqt->tqt_thread == NULL) {
+		kmem_free(tqt, sizeof (taskq_thread_t));
+		return (NULL);
+	}
+
+	if (spl_taskq_thread_bind) {
+		last_used_cpu = (last_used_cpu + 1) % num_online_cpus();
+		kthread_bind(tqt->tqt_thread, last_used_cpu);
+	}
+
+	if (spl_taskq_thread_priority)
+		set_user_nice(tqt->tqt_thread, PRIO_TO_NICE(tq->tq_pri));
+
+	wake_up_process(tqt->tqt_thread);
+
+	return (tqt);
+}
+
+taskq_t *
+taskq_create(const char *name, int nthreads, pri_t pri,
+    int minalloc, int maxalloc, uint_t flags)
+{
+	taskq_t *tq;
+	taskq_thread_t *tqt;
+	int count = 0, rc = 0, i;
+	unsigned long irqflags;
+
+	ASSERT(name != NULL);
+	ASSERT(minalloc >= 0);
+	ASSERT(maxalloc <= INT_MAX);
+	ASSERT(!(flags & (TASKQ_CPR_SAFE))); /* Unsupported */
+
+	/* Scale the number of threads using nthreads as a percentage */
+	if (flags & TASKQ_THREADS_CPU_PCT) {
+		ASSERT(nthreads <= 100);
+		ASSERT(nthreads >= 0);
+		nthreads = MIN(nthreads, 100);
+		nthreads = MAX(nthreads, 0);
+		nthreads = MAX((num_online_cpus() * nthreads) / 100, 1);
+	}
+
+	tq = kmem_alloc(sizeof (*tq), KM_PUSHPAGE);
+	if (tq == NULL)
+		return (NULL);
+
+	spin_lock_init(&tq->tq_lock);
+	INIT_LIST_HEAD(&tq->tq_thread_list);
+	INIT_LIST_HEAD(&tq->tq_active_list);
+	tq->tq_name = strdup(name);
+	tq->tq_nactive = 0;
+	tq->tq_nthreads = 0;
+	tq->tq_nspawn = 0;
+	tq->tq_maxthreads = nthreads;
+	tq->tq_pri = pri;
+	tq->tq_minalloc = minalloc;
+	tq->tq_maxalloc = maxalloc;
+	tq->tq_nalloc = 0;
+	tq->tq_flags = (flags | TASKQ_ACTIVE);
+	tq->tq_next_id = TASKQID_INITIAL;
+	tq->tq_lowest_id = TASKQID_INITIAL;
+	INIT_LIST_HEAD(&tq->tq_free_list);
+	INIT_LIST_HEAD(&tq->tq_pend_list);
+	INIT_LIST_HEAD(&tq->tq_prio_list);
+	INIT_LIST_HEAD(&tq->tq_delay_list);
+	init_waitqueue_head(&tq->tq_work_waitq);
+	init_waitqueue_head(&tq->tq_wait_waitq);
+	tq->tq_lock_class = TQ_LOCK_GENERAL;
+	INIT_LIST_HEAD(&tq->tq_taskqs);
+
+	if (flags & TASKQ_PREPOPULATE) {
+		spin_lock_irqsave_nested(&tq->tq_lock, irqflags,
+		    tq->tq_lock_class);
+
+		for (i = 0; i < minalloc; i++)
+			task_done(tq, task_alloc(tq, TQ_PUSHPAGE | TQ_NEW,
+			    &irqflags));
+
+		spin_unlock_irqrestore(&tq->tq_lock, irqflags);
+	}
+
+	if ((flags & TASKQ_DYNAMIC) && spl_taskq_thread_dynamic)
+		nthreads = 1;
+
+	for (i = 0; i < nthreads; i++) {
+		tqt = taskq_thread_create(tq);
+		if (tqt == NULL)
+			rc = 1;
+		else
+			count++;
+	}
+
+	/* Wait for all threads to be started before potential destroy */
+	wait_event(tq->tq_wait_waitq, tq->tq_nthreads == count);
+	/*
+	 * taskq_thread might have touched nspawn, but we don't want them to
+	 * because they're not dynamically spawned. So we reset it to 0
+	 */
+	tq->tq_nspawn = 0;
+
+	if (rc) {
+		taskq_destroy(tq);
+		tq = NULL;
+	} else {
+		down_write(&tq_list_sem);
+		tq->tq_instance = taskq_find_by_name(name) + 1;
+		list_add_tail(&tq->tq_taskqs, &tq_list);
+		up_write(&tq_list_sem);
+	}
+
+	return (tq);
+}
+EXPORT_SYMBOL(taskq_create);
+
+void
+taskq_destroy(taskq_t *tq)
+{
+	struct task_struct *thread;
+	taskq_thread_t *tqt;
+	taskq_ent_t *t;
+	unsigned long flags;
+
+	ASSERT(tq);
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	tq->tq_flags &= ~TASKQ_ACTIVE;
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	/*
+	 * When TASKQ_ACTIVE is clear new tasks may not be added nor may
+	 * new worker threads be spawned for dynamic taskq.
+	 */
+	if (dynamic_taskq != NULL)
+		taskq_wait_outstanding(dynamic_taskq, 0);
+
+	taskq_wait(tq);
+
+	/* remove taskq from global list used by the kstats */
+	down_write(&tq_list_sem);
+	list_del(&tq->tq_taskqs);
+	up_write(&tq_list_sem);
+
+	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
+	/* wait for spawning threads to insert themselves to the list */
+	while (tq->tq_nspawn) {
+		spin_unlock_irqrestore(&tq->tq_lock, flags);
+		schedule_timeout_interruptible(1);
+		spin_lock_irqsave_nested(&tq->tq_lock, flags,
+		    tq->tq_lock_class);
+	}
+
+	/*
+	 * Signal each thread to exit and block until it does.  Each thread
+	 * is responsible for removing itself from the list and freeing its
+	 * taskq_thread_t.  This allows for idle threads to opt to remove
+	 * themselves from the taskq.  They can be recreated as needed.
+	 */
+	while (!list_empty(&tq->tq_thread_list)) {
+		tqt = list_entry(tq->tq_thread_list.next,
+		    taskq_thread_t, tqt_thread_list);
+		thread = tqt->tqt_thread;
+		spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+		kthread_stop(thread);
+
+		spin_lock_irqsave_nested(&tq->tq_lock, flags,
+		    tq->tq_lock_class);
+	}
+
+	while (!list_empty(&tq->tq_free_list)) {
+		t = list_entry(tq->tq_free_list.next, taskq_ent_t, tqent_list);
+
+		ASSERT(!(t->tqent_flags & TQENT_FLAG_PREALLOC));
+
+		list_del_init(&t->tqent_list);
+		task_free(tq, t);
+	}
+
+	ASSERT0(tq->tq_nthreads);
+	ASSERT0(tq->tq_nalloc);
+	ASSERT0(tq->tq_nspawn);
+	ASSERT(list_empty(&tq->tq_thread_list));
+	ASSERT(list_empty(&tq->tq_active_list));
+	ASSERT(list_empty(&tq->tq_free_list));
+	ASSERT(list_empty(&tq->tq_pend_list));
+	ASSERT(list_empty(&tq->tq_prio_list));
+	ASSERT(list_empty(&tq->tq_delay_list));
+
+	spin_unlock_irqrestore(&tq->tq_lock, flags);
+
+	strfree(tq->tq_name);
+	kmem_free(tq, sizeof (taskq_t));
+}
+EXPORT_SYMBOL(taskq_destroy);
+
+
+static unsigned int spl_taskq_kick = 0;
+
+/*
+ * 2.6.36 API Change
+ * module_param_cb is introduced to take kernel_param_ops and
+ * module_param_call is marked as obsolete. Also set and get operations
+ * were changed to take a 'const struct kernel_param *'.
+ */
+static int
+#ifdef module_param_cb
+param_set_taskq_kick(const char *val, const struct kernel_param *kp)
+#else
+param_set_taskq_kick(const char *val, struct kernel_param *kp)
+#endif
+{
+	int ret;
+	taskq_t *tq;
+	taskq_ent_t *t;
+	unsigned long flags;
+
+	ret = param_set_uint(val, kp);
+	if (ret < 0 || !spl_taskq_kick)
+		return (ret);
+	/* reset value */
+	spl_taskq_kick = 0;
+
+	down_read(&tq_list_sem);
+	list_for_each_entry(tq, &tq_list, tq_taskqs) {
+		spin_lock_irqsave_nested(&tq->tq_lock, flags,
+		    tq->tq_lock_class);
+		/* Check if the first pending is older than 5 seconds */
+		t = taskq_next_ent(tq);
+		if (t && time_after(jiffies, t->tqent_birth + 5*HZ)) {
+			(void) taskq_thread_spawn(tq);
+			printk(KERN_INFO "spl: Kicked taskq %s/%d\n",
+			    tq->tq_name, tq->tq_instance);
+		}
+		spin_unlock_irqrestore(&tq->tq_lock, flags);
+	}
+	up_read(&tq_list_sem);
+	return (ret);
+}
+
+#ifdef module_param_cb
+static const struct kernel_param_ops param_ops_taskq_kick = {
+	.set = param_set_taskq_kick,
+	.get = param_get_uint,
+};
+module_param_cb(spl_taskq_kick, &param_ops_taskq_kick, &spl_taskq_kick, 0644);
+#else
+module_param_call(spl_taskq_kick, param_set_taskq_kick, param_get_uint,
+	&spl_taskq_kick, 0644);
+#endif
+MODULE_PARM_DESC(spl_taskq_kick,
+	"Write nonzero to kick stuck taskqs to spawn more threads");
+
+int
+spl_taskq_init(void)
+{
+	tsd_create(&taskq_tsd, NULL);
+
+	system_taskq = taskq_create("spl_system_taskq", MAX(boot_ncpus, 64),
+	    maxclsyspri, boot_ncpus, INT_MAX, TASKQ_PREPOPULATE|TASKQ_DYNAMIC);
+	if (system_taskq == NULL)
+		return (1);
+
+	system_delay_taskq = taskq_create("spl_delay_taskq", MAX(boot_ncpus, 4),
+	    maxclsyspri, boot_ncpus, INT_MAX, TASKQ_PREPOPULATE|TASKQ_DYNAMIC);
+	if (system_delay_taskq == NULL) {
+		taskq_destroy(system_taskq);
+		return (1);
+	}
+
+	dynamic_taskq = taskq_create("spl_dynamic_taskq", 1,
+	    maxclsyspri, boot_ncpus, INT_MAX, TASKQ_PREPOPULATE);
+	if (dynamic_taskq == NULL) {
+		taskq_destroy(system_taskq);
+		taskq_destroy(system_delay_taskq);
+		return (1);
+	}
+
+	/*
+	 * This is used to annotate tq_lock, so
+	 *   taskq_dispatch -> taskq_thread_spawn -> taskq_dispatch
+	 * does not trigger a lockdep warning re: possible recursive locking
+	 */
+	dynamic_taskq->tq_lock_class = TQ_LOCK_DYNAMIC;
+
+	return (0);
+}
+
+void
+spl_taskq_fini(void)
+{
+	taskq_destroy(dynamic_taskq);
+	dynamic_taskq = NULL;
+
+	taskq_destroy(system_delay_taskq);
+	system_delay_taskq = NULL;
+
+	taskq_destroy(system_taskq);
+	system_taskq = NULL;
+
+	tsd_destroy(&taskq_tsd);
+}
diff --git a/module/spl/spl-thread.c b/module/spl/spl-thread.c
new file mode 100644
index 000000000..d441ad65f
--- /dev/null
+++ b/module/spl/spl-thread.c
@@ -0,0 +1,160 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Thread Implementation.
+ */
+
+#include <sys/thread.h>
+#include <sys/kmem.h>
+#include <sys/tsd.h>
+
+/*
+ * Thread interfaces
+ */
+typedef struct thread_priv_s {
+	unsigned long tp_magic;		/* Magic */
+	int tp_name_size;		/* Name size */
+	char *tp_name;			/* Name (without _thread suffix) */
+	void (*tp_func)(void *);	/* Registered function */
+	void *tp_args;			/* Args to be passed to function */
+	size_t tp_len;			/* Len to be passed to function */
+	int tp_state;			/* State to start thread at */
+	pri_t tp_pri;			/* Priority to start threat at */
+} thread_priv_t;
+
+static int
+thread_generic_wrapper(void *arg)
+{
+	thread_priv_t *tp = (thread_priv_t *)arg;
+	void (*func)(void *);
+	void *args;
+
+	ASSERT(tp->tp_magic == TP_MAGIC);
+	func = tp->tp_func;
+	args = tp->tp_args;
+	set_current_state(tp->tp_state);
+	set_user_nice((kthread_t *)current, PRIO_TO_NICE(tp->tp_pri));
+	kmem_free(tp->tp_name, tp->tp_name_size);
+	kmem_free(tp, sizeof (thread_priv_t));
+
+	if (func)
+		func(args);
+
+	return (0);
+}
+
+void
+__thread_exit(void)
+{
+	tsd_exit();
+	complete_and_exit(NULL, 0);
+	/* Unreachable */
+}
+EXPORT_SYMBOL(__thread_exit);
+
+/*
+ * thread_create() may block forever if it cannot create a thread or
+ * allocate memory.  This is preferable to returning a NULL which Solaris
+ * style callers likely never check for... since it can't fail.
+ */
+kthread_t *
+__thread_create(caddr_t stk, size_t  stksize, thread_func_t func,
+    const char *name, void *args, size_t len, proc_t *pp, int state, pri_t pri)
+{
+	thread_priv_t *tp;
+	struct task_struct *tsk;
+	char *p;
+
+	/* Option pp is simply ignored */
+	/* Variable stack size unsupported */
+	ASSERT(stk == NULL);
+
+	tp = kmem_alloc(sizeof (thread_priv_t), KM_PUSHPAGE);
+	if (tp == NULL)
+		return (NULL);
+
+	tp->tp_magic = TP_MAGIC;
+	tp->tp_name_size = strlen(name) + 1;
+
+	tp->tp_name = kmem_alloc(tp->tp_name_size, KM_PUSHPAGE);
+	if (tp->tp_name == NULL) {
+		kmem_free(tp, sizeof (thread_priv_t));
+		return (NULL);
+	}
+
+	strncpy(tp->tp_name, name, tp->tp_name_size);
+
+	/*
+	 * Strip trailing "_thread" from passed name which will be the func
+	 * name since the exposed API has no parameter for passing a name.
+	 */
+	p = strstr(tp->tp_name, "_thread");
+	if (p)
+		p[0] = '\0';
+
+	tp->tp_func  = func;
+	tp->tp_args  = args;
+	tp->tp_len   = len;
+	tp->tp_state = state;
+	tp->tp_pri   = pri;
+
+	tsk = spl_kthread_create(thread_generic_wrapper, (void *)tp,
+	    "%s", tp->tp_name);
+	if (IS_ERR(tsk))
+		return (NULL);
+
+	wake_up_process(tsk);
+	return ((kthread_t *)tsk);
+}
+EXPORT_SYMBOL(__thread_create);
+
+/*
+ * spl_kthread_create - Wrapper providing pre-3.13 semantics for
+ * kthread_create() in which it is not killable and less likely
+ * to return -ENOMEM.
+ */
+struct task_struct *
+spl_kthread_create(int (*func)(void *), void *data, const char namefmt[], ...)
+{
+	struct task_struct *tsk;
+	va_list args;
+	char name[TASK_COMM_LEN];
+
+	va_start(args, namefmt);
+	vsnprintf(name, sizeof (name), namefmt, args);
+	va_end(args);
+	do {
+		tsk = kthread_create(func, data, "%s", name);
+		if (IS_ERR(tsk)) {
+			if (signal_pending(current)) {
+				clear_thread_flag(TIF_SIGPENDING);
+				continue;
+			}
+			if (PTR_ERR(tsk) == -ENOMEM)
+				continue;
+			return (NULL);
+		} else
+			return (tsk);
+	} while (1);
+}
+EXPORT_SYMBOL(spl_kthread_create);
diff --git a/module/spl/spl-tsd.c b/module/spl/spl-tsd.c
new file mode 100644
index 000000000..4c800292a
--- /dev/null
+++ b/module/spl/spl-tsd.c
@@ -0,0 +1,720 @@
+/*
+ *  Copyright (C) 2010 Lawrence Livermore National Security, LLC.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ *  Solaris Porting Layer (SPL) Thread Specific Data Implementation.
+ *
+ *  Thread specific data has implemented using a hash table, this avoids
+ *  the need to add a member to the task structure and allows maximum
+ *  portability between kernels.  This implementation has been optimized
+ *  to keep the tsd_set() and tsd_get() times as small as possible.
+ *
+ *  The majority of the entries in the hash table are for specific tsd
+ *  entries.  These entries are hashed by the product of their key and
+ *  pid because by design the key and pid are guaranteed to be unique.
+ *  Their product also has the desirable properly that it will be uniformly
+ *  distributed over the hash bins providing neither the pid nor key is zero.
+ *  Under linux the zero pid is always the init process and thus won't be
+ *  used, and this implementation is careful to never to assign a zero key.
+ *  By default the hash table is sized to 512 bins which is expected to
+ *  be sufficient for light to moderate usage of thread specific data.
+ *
+ *  The hash table contains two additional type of entries.  They first
+ *  type is entry is called a 'key' entry and it is added to the hash during
+ *  tsd_create().  It is used to store the address of the destructor function
+ *  and it is used as an anchor point.  All tsd entries which use the same
+ *  key will be linked to this entry.  This is used during tsd_destory() to
+ *  quickly call the destructor function for all tsd associated with the key.
+ *  The 'key' entry may be looked up with tsd_hash_search() by passing the
+ *  key you wish to lookup and DTOR_PID constant as the pid.
+ *
+ *  The second type of entry is called a 'pid' entry and it is added to the
+ *  hash the first time a process set a key.  The 'pid' entry is also used
+ *  as an anchor and all tsd for the process will be linked to it.  This
+ *  list is using during tsd_exit() to ensure all registered destructors
+ *  are run for the process.  The 'pid' entry may be looked up with
+ *  tsd_hash_search() by passing the PID_KEY constant as the key, and
+ *  the process pid.  Note that tsd_exit() is called by thread_exit()
+ *  so if your using the Solaris thread API you should not need to call
+ *  tsd_exit() directly.
+ *
+ */
+
+#include <sys/kmem.h>
+#include <sys/thread.h>
+#include <sys/tsd.h>
+#include <linux/hash.h>
+
+typedef struct tsd_hash_bin {
+	spinlock_t		hb_lock;
+	struct hlist_head	hb_head;
+} tsd_hash_bin_t;
+
+typedef struct tsd_hash_table {
+	spinlock_t		ht_lock;
+	uint_t			ht_bits;
+	uint_t			ht_key;
+	tsd_hash_bin_t		*ht_bins;
+} tsd_hash_table_t;
+
+typedef struct tsd_hash_entry {
+	uint_t			he_key;
+	pid_t			he_pid;
+	dtor_func_t		he_dtor;
+	void			*he_value;
+	struct hlist_node	he_list;
+	struct list_head	he_key_list;
+	struct list_head	he_pid_list;
+} tsd_hash_entry_t;
+
+static tsd_hash_table_t *tsd_hash_table = NULL;
+
+
+/*
+ * tsd_hash_search - searches hash table for tsd_hash_entry
+ * @table: hash table
+ * @key: search key
+ * @pid: search pid
+ */
+static tsd_hash_entry_t *
+tsd_hash_search(tsd_hash_table_t *table, uint_t key, pid_t pid)
+{
+	struct hlist_node *node;
+	tsd_hash_entry_t *entry;
+	tsd_hash_bin_t *bin;
+	ulong_t hash;
+
+	hash = hash_long((ulong_t)key * (ulong_t)pid, table->ht_bits);
+	bin = &table->ht_bins[hash];
+	spin_lock(&bin->hb_lock);
+	hlist_for_each(node, &bin->hb_head) {
+		entry = list_entry(node, tsd_hash_entry_t, he_list);
+		if ((entry->he_key == key) && (entry->he_pid == pid)) {
+			spin_unlock(&bin->hb_lock);
+			return (entry);
+		}
+	}
+
+	spin_unlock(&bin->hb_lock);
+	return (NULL);
+}
+
+/*
+ * tsd_hash_dtor - call the destructor and free all entries on the list
+ * @work: list of hash entries
+ *
+ * For a list of entries which have all already been removed from the
+ * hash call their registered destructor then free the associated memory.
+ */
+static void
+tsd_hash_dtor(struct hlist_head *work)
+{
+	tsd_hash_entry_t *entry;
+
+	while (!hlist_empty(work)) {
+		entry = hlist_entry(work->first, tsd_hash_entry_t, he_list);
+		hlist_del(&entry->he_list);
+
+		if (entry->he_dtor && entry->he_pid != DTOR_PID)
+			entry->he_dtor(entry->he_value);
+
+		kmem_free(entry, sizeof (tsd_hash_entry_t));
+	}
+}
+
+/*
+ * tsd_hash_add - adds an entry to hash table
+ * @table: hash table
+ * @key: search key
+ * @pid: search pid
+ *
+ * The caller is responsible for ensuring the unique key/pid do not
+ * already exist in the hash table.  This possible because all entries
+ * are thread specific thus a concurrent thread will never attempt to
+ * add this key/pid.  Because multiple bins must be checked to add
+ * links to the dtor and pid entries the entire table is locked.
+ */
+static int
+tsd_hash_add(tsd_hash_table_t *table, uint_t key, pid_t pid, void *value)
+{
+	tsd_hash_entry_t *entry, *dtor_entry, *pid_entry;
+	tsd_hash_bin_t *bin;
+	ulong_t hash;
+	int rc = 0;
+
+	ASSERT3P(tsd_hash_search(table, key, pid), ==, NULL);
+
+	/* New entry allocate structure, set value, and add to hash */
+	entry = kmem_alloc(sizeof (tsd_hash_entry_t), KM_PUSHPAGE);
+	if (entry == NULL)
+		return (ENOMEM);
+
+	entry->he_key = key;
+	entry->he_pid = pid;
+	entry->he_value = value;
+	INIT_HLIST_NODE(&entry->he_list);
+	INIT_LIST_HEAD(&entry->he_key_list);
+	INIT_LIST_HEAD(&entry->he_pid_list);
+
+	spin_lock(&table->ht_lock);
+
+	/* Destructor entry must exist for all valid keys */
+	dtor_entry = tsd_hash_search(table, entry->he_key, DTOR_PID);
+	ASSERT3P(dtor_entry, !=, NULL);
+	entry->he_dtor = dtor_entry->he_dtor;
+
+	/* Process entry must exist for all valid processes */
+	pid_entry = tsd_hash_search(table, PID_KEY, entry->he_pid);
+	ASSERT3P(pid_entry, !=, NULL);
+
+	hash = hash_long((ulong_t)key * (ulong_t)pid, table->ht_bits);
+	bin = &table->ht_bins[hash];
+	spin_lock(&bin->hb_lock);
+
+	/* Add to the hash, key, and pid lists */
+	hlist_add_head(&entry->he_list, &bin->hb_head);
+	list_add(&entry->he_key_list, &dtor_entry->he_key_list);
+	list_add(&entry->he_pid_list, &pid_entry->he_pid_list);
+
+	spin_unlock(&bin->hb_lock);
+	spin_unlock(&table->ht_lock);
+
+	return (rc);
+}
+
+/*
+ * tsd_hash_add_key - adds a destructor entry to the hash table
+ * @table: hash table
+ * @keyp: search key
+ * @dtor: key destructor
+ *
+ * For every unique key there is a single entry in the hash which is used
+ * as anchor.  All other thread specific entries for this key are linked
+ * to this anchor via the 'he_key_list' list head.  On return they keyp
+ * will be set to the next available key for the hash table.
+ */
+static int
+tsd_hash_add_key(tsd_hash_table_t *table, uint_t *keyp, dtor_func_t dtor)
+{
+	tsd_hash_entry_t *tmp_entry, *entry;
+	tsd_hash_bin_t *bin;
+	ulong_t hash;
+	int keys_checked = 0;
+
+	ASSERT3P(table, !=, NULL);
+
+	/* Allocate entry to be used as a destructor for this key */
+	entry = kmem_alloc(sizeof (tsd_hash_entry_t), KM_PUSHPAGE);
+	if (entry == NULL)
+		return (ENOMEM);
+
+	/* Determine next available key value */
+	spin_lock(&table->ht_lock);
+	do {
+		/* Limited to TSD_KEYS_MAX concurrent unique keys */
+		if (table->ht_key++ > TSD_KEYS_MAX)
+			table->ht_key = 1;
+
+		/* Ensure failure when all TSD_KEYS_MAX keys are in use */
+		if (keys_checked++ >= TSD_KEYS_MAX) {
+			spin_unlock(&table->ht_lock);
+			return (ENOENT);
+		}
+
+		tmp_entry = tsd_hash_search(table, table->ht_key, DTOR_PID);
+	} while (tmp_entry);
+
+	/* Add destructor entry in to hash table */
+	entry->he_key = *keyp = table->ht_key;
+	entry->he_pid = DTOR_PID;
+	entry->he_dtor = dtor;
+	entry->he_value = NULL;
+	INIT_HLIST_NODE(&entry->he_list);
+	INIT_LIST_HEAD(&entry->he_key_list);
+	INIT_LIST_HEAD(&entry->he_pid_list);
+
+	hash = hash_long((ulong_t)*keyp * (ulong_t)DTOR_PID, table->ht_bits);
+	bin = &table->ht_bins[hash];
+	spin_lock(&bin->hb_lock);
+
+	hlist_add_head(&entry->he_list, &bin->hb_head);
+
+	spin_unlock(&bin->hb_lock);
+	spin_unlock(&table->ht_lock);
+
+	return (0);
+}
+
+/*
+ * tsd_hash_add_pid - adds a process entry to the hash table
+ * @table: hash table
+ * @pid: search pid
+ *
+ * For every process these is a single entry in the hash which is used
+ * as anchor.  All other thread specific entries for this process are
+ * linked to this anchor via the 'he_pid_list' list head.
+ */
+static int
+tsd_hash_add_pid(tsd_hash_table_t *table, pid_t pid)
+{
+	tsd_hash_entry_t *entry;
+	tsd_hash_bin_t *bin;
+	ulong_t hash;
+
+	/* Allocate entry to be used as the process reference */
+	entry = kmem_alloc(sizeof (tsd_hash_entry_t), KM_PUSHPAGE);
+	if (entry == NULL)
+		return (ENOMEM);
+
+	spin_lock(&table->ht_lock);
+	entry->he_key = PID_KEY;
+	entry->he_pid = pid;
+	entry->he_dtor = NULL;
+	entry->he_value = NULL;
+	INIT_HLIST_NODE(&entry->he_list);
+	INIT_LIST_HEAD(&entry->he_key_list);
+	INIT_LIST_HEAD(&entry->he_pid_list);
+
+	hash = hash_long((ulong_t)PID_KEY * (ulong_t)pid, table->ht_bits);
+	bin = &table->ht_bins[hash];
+	spin_lock(&bin->hb_lock);
+
+	hlist_add_head(&entry->he_list, &bin->hb_head);
+
+	spin_unlock(&bin->hb_lock);
+	spin_unlock(&table->ht_lock);
+
+	return (0);
+}
+
+/*
+ * tsd_hash_del - delete an entry from hash table, key, and pid lists
+ * @table: hash table
+ * @key: search key
+ * @pid: search pid
+ */
+static void
+tsd_hash_del(tsd_hash_table_t *table, tsd_hash_entry_t *entry)
+{
+	hlist_del(&entry->he_list);
+	list_del_init(&entry->he_key_list);
+	list_del_init(&entry->he_pid_list);
+}
+
+/*
+ * tsd_hash_table_init - allocate a hash table
+ * @bits: hash table size
+ *
+ * A hash table with 2^bits bins will be created, it may not be resized
+ * after the fact and must be free'd with tsd_hash_table_fini().
+ */
+static tsd_hash_table_t *
+tsd_hash_table_init(uint_t bits)
+{
+	tsd_hash_table_t *table;
+	int hash, size = (1 << bits);
+
+	table = kmem_zalloc(sizeof (tsd_hash_table_t), KM_SLEEP);
+	if (table == NULL)
+		return (NULL);
+
+	table->ht_bins = kmem_zalloc(sizeof (tsd_hash_bin_t) * size, KM_SLEEP);
+	if (table->ht_bins == NULL) {
+		kmem_free(table, sizeof (tsd_hash_table_t));
+		return (NULL);
+	}
+
+	for (hash = 0; hash < size; hash++) {
+		spin_lock_init(&table->ht_bins[hash].hb_lock);
+		INIT_HLIST_HEAD(&table->ht_bins[hash].hb_head);
+	}
+
+	spin_lock_init(&table->ht_lock);
+	table->ht_bits = bits;
+	table->ht_key = 1;
+
+	return (table);
+}
+
+/*
+ * tsd_hash_table_fini - free a hash table
+ * @table: hash table
+ *
+ * Free a hash table allocated by tsd_hash_table_init().  If the hash
+ * table is not empty this function will call the proper destructor for
+ * all remaining entries before freeing the memory used by those entries.
+ */
+static void
+tsd_hash_table_fini(tsd_hash_table_t *table)
+{
+	HLIST_HEAD(work);
+	tsd_hash_bin_t *bin;
+	tsd_hash_entry_t *entry;
+	int size, i;
+
+	ASSERT3P(table, !=, NULL);
+	spin_lock(&table->ht_lock);
+	for (i = 0, size = (1 << table->ht_bits); i < size; i++) {
+		bin = &table->ht_bins[i];
+		spin_lock(&bin->hb_lock);
+		while (!hlist_empty(&bin->hb_head)) {
+			entry = hlist_entry(bin->hb_head.first,
+			    tsd_hash_entry_t, he_list);
+			tsd_hash_del(table, entry);
+			hlist_add_head(&entry->he_list, &work);
+		}
+		spin_unlock(&bin->hb_lock);
+	}
+	spin_unlock(&table->ht_lock);
+
+	tsd_hash_dtor(&work);
+	kmem_free(table->ht_bins, sizeof (tsd_hash_bin_t)*(1<<table->ht_bits));
+	kmem_free(table, sizeof (tsd_hash_table_t));
+}
+
+/*
+ * tsd_remove_entry - remove a tsd entry for this thread
+ * @entry: entry to remove
+ *
+ * Remove the thread specific data @entry for this thread.
+ * If this is the last entry for this thread, also remove the PID entry.
+ */
+static void
+tsd_remove_entry(tsd_hash_entry_t *entry)
+{
+	HLIST_HEAD(work);
+	tsd_hash_table_t *table;
+	tsd_hash_entry_t *pid_entry;
+	tsd_hash_bin_t *pid_entry_bin, *entry_bin;
+	ulong_t hash;
+
+	table = tsd_hash_table;
+	ASSERT3P(table, !=, NULL);
+	ASSERT3P(entry, !=, NULL);
+
+	spin_lock(&table->ht_lock);
+
+	hash = hash_long((ulong_t)entry->he_key *
+	    (ulong_t)entry->he_pid, table->ht_bits);
+	entry_bin = &table->ht_bins[hash];
+
+	/* save the possible pid_entry */
+	pid_entry = list_entry(entry->he_pid_list.next, tsd_hash_entry_t,
+	    he_pid_list);
+
+	/* remove entry */
+	spin_lock(&entry_bin->hb_lock);
+	tsd_hash_del(table, entry);
+	hlist_add_head(&entry->he_list, &work);
+	spin_unlock(&entry_bin->hb_lock);
+
+	/* if pid_entry is indeed pid_entry, then remove it if it's empty */
+	if (pid_entry->he_key == PID_KEY &&
+	    list_empty(&pid_entry->he_pid_list)) {
+		hash = hash_long((ulong_t)pid_entry->he_key *
+		    (ulong_t)pid_entry->he_pid, table->ht_bits);
+		pid_entry_bin = &table->ht_bins[hash];
+
+		spin_lock(&pid_entry_bin->hb_lock);
+		tsd_hash_del(table, pid_entry);
+		hlist_add_head(&pid_entry->he_list, &work);
+		spin_unlock(&pid_entry_bin->hb_lock);
+	}
+
+	spin_unlock(&table->ht_lock);
+
+	tsd_hash_dtor(&work);
+}
+
+/*
+ * tsd_set - set thread specific data
+ * @key: lookup key
+ * @value: value to set
+ *
+ * Caller must prevent racing tsd_create() or tsd_destroy(), protected
+ * from racing tsd_get() or tsd_set() because it is thread specific.
+ * This function has been optimized to be fast for the update case.
+ * When setting the tsd initially it will be slower due to additional
+ * required locking and potential memory allocations.
+ */
+int
+tsd_set(uint_t key, void *value)
+{
+	tsd_hash_table_t *table;
+	tsd_hash_entry_t *entry;
+	pid_t pid;
+	int rc;
+	/* mark remove if value is NULL */
+	boolean_t remove = (value == NULL);
+
+	table = tsd_hash_table;
+	pid = curthread->pid;
+	ASSERT3P(table, !=, NULL);
+
+	if ((key == 0) || (key > TSD_KEYS_MAX))
+		return (EINVAL);
+
+	/* Entry already exists in hash table update value */
+	entry = tsd_hash_search(table, key, pid);
+	if (entry) {
+		entry->he_value = value;
+		/* remove the entry */
+		if (remove)
+			tsd_remove_entry(entry);
+		return (0);
+	}
+
+	/* don't create entry if value is NULL */
+	if (remove)
+		return (0);
+
+	/* Add a process entry to the hash if not yet exists */
+	entry = tsd_hash_search(table, PID_KEY, pid);
+	if (entry == NULL) {
+		rc = tsd_hash_add_pid(table, pid);
+		if (rc)
+			return (rc);
+	}
+
+	rc = tsd_hash_add(table, key, pid, value);
+	return (rc);
+}
+EXPORT_SYMBOL(tsd_set);
+
+/*
+ * tsd_get - get thread specific data
+ * @key: lookup key
+ *
+ * Caller must prevent racing tsd_create() or tsd_destroy().  This
+ * implementation is designed to be fast and scalable, it does not
+ * lock the entire table only a single hash bin.
+ */
+void *
+tsd_get(uint_t key)
+{
+	tsd_hash_entry_t *entry;
+
+	ASSERT3P(tsd_hash_table, !=, NULL);
+
+	if ((key == 0) || (key > TSD_KEYS_MAX))
+		return (NULL);
+
+	entry = tsd_hash_search(tsd_hash_table, key, curthread->pid);
+	if (entry == NULL)
+		return (NULL);
+
+	return (entry->he_value);
+}
+EXPORT_SYMBOL(tsd_get);
+
+/*
+ * tsd_get_by_thread - get thread specific data for specified thread
+ * @key: lookup key
+ * @thread: thread to lookup
+ *
+ * Caller must prevent racing tsd_create() or tsd_destroy().  This
+ * implementation is designed to be fast and scalable, it does not
+ * lock the entire table only a single hash bin.
+ */
+void *
+tsd_get_by_thread(uint_t key, kthread_t *thread)
+{
+	tsd_hash_entry_t *entry;
+
+	ASSERT3P(tsd_hash_table, !=, NULL);
+
+	if ((key == 0) || (key > TSD_KEYS_MAX))
+		return (NULL);
+
+	entry = tsd_hash_search(tsd_hash_table, key, thread->pid);
+	if (entry == NULL)
+		return (NULL);
+
+	return (entry->he_value);
+}
+EXPORT_SYMBOL(tsd_get_by_thread);
+
+/*
+ * tsd_create - create thread specific data key
+ * @keyp: lookup key address
+ * @dtor: destructor called during tsd_destroy() or tsd_exit()
+ *
+ * Provided key must be set to 0 or it assumed to be already in use.
+ * The dtor is allowed to be NULL in which case no additional cleanup
+ * for the data is performed during tsd_destroy() or tsd_exit().
+ *
+ * Caller must prevent racing tsd_set() or tsd_get(), this function is
+ * safe from racing tsd_create(), tsd_destroy(), and tsd_exit().
+ */
+void
+tsd_create(uint_t *keyp, dtor_func_t dtor)
+{
+	ASSERT3P(keyp, !=, NULL);
+	if (*keyp)
+		return;
+
+	(void) tsd_hash_add_key(tsd_hash_table, keyp, dtor);
+}
+EXPORT_SYMBOL(tsd_create);
+
+/*
+ * tsd_destroy - destroy thread specific data
+ * @keyp: lookup key address
+ *
+ * Destroys the thread specific data on all threads which use this key.
+ *
+ * Caller must prevent racing tsd_set() or tsd_get(), this function is
+ * safe from racing tsd_create(), tsd_destroy(), and tsd_exit().
+ */
+void
+tsd_destroy(uint_t *keyp)
+{
+	HLIST_HEAD(work);
+	tsd_hash_table_t *table;
+	tsd_hash_entry_t *dtor_entry, *entry;
+	tsd_hash_bin_t *dtor_entry_bin, *entry_bin;
+	ulong_t hash;
+
+	table = tsd_hash_table;
+	ASSERT3P(table, !=, NULL);
+
+	spin_lock(&table->ht_lock);
+	dtor_entry = tsd_hash_search(table, *keyp, DTOR_PID);
+	if (dtor_entry == NULL) {
+		spin_unlock(&table->ht_lock);
+		return;
+	}
+
+	/*
+	 * All threads which use this key must be linked off of the
+	 * DTOR_PID entry.  They are removed from the hash table and
+	 * linked in to a private working list to be destroyed.
+	 */
+	while (!list_empty(&dtor_entry->he_key_list)) {
+		entry = list_entry(dtor_entry->he_key_list.next,
+		    tsd_hash_entry_t, he_key_list);
+		ASSERT3U(dtor_entry->he_key, ==, entry->he_key);
+		ASSERT3P(dtor_entry->he_dtor, ==, entry->he_dtor);
+
+		hash = hash_long((ulong_t)entry->he_key *
+		    (ulong_t)entry->he_pid, table->ht_bits);
+		entry_bin = &table->ht_bins[hash];
+
+		spin_lock(&entry_bin->hb_lock);
+		tsd_hash_del(table, entry);
+		hlist_add_head(&entry->he_list, &work);
+		spin_unlock(&entry_bin->hb_lock);
+	}
+
+	hash = hash_long((ulong_t)dtor_entry->he_key *
+	    (ulong_t)dtor_entry->he_pid, table->ht_bits);
+	dtor_entry_bin = &table->ht_bins[hash];
+
+	spin_lock(&dtor_entry_bin->hb_lock);
+	tsd_hash_del(table, dtor_entry);
+	hlist_add_head(&dtor_entry->he_list, &work);
+	spin_unlock(&dtor_entry_bin->hb_lock);
+	spin_unlock(&table->ht_lock);
+
+	tsd_hash_dtor(&work);
+	*keyp = 0;
+}
+EXPORT_SYMBOL(tsd_destroy);
+
+/*
+ * tsd_exit - destroys all thread specific data for this thread
+ *
+ * Destroys all the thread specific data for this thread.
+ *
+ * Caller must prevent racing tsd_set() or tsd_get(), this function is
+ * safe from racing tsd_create(), tsd_destroy(), and tsd_exit().
+ */
+void
+tsd_exit(void)
+{
+	HLIST_HEAD(work);
+	tsd_hash_table_t *table;
+	tsd_hash_entry_t *pid_entry, *entry;
+	tsd_hash_bin_t *pid_entry_bin, *entry_bin;
+	ulong_t hash;
+
+	table = tsd_hash_table;
+	ASSERT3P(table, !=, NULL);
+
+	spin_lock(&table->ht_lock);
+	pid_entry = tsd_hash_search(table, PID_KEY, curthread->pid);
+	if (pid_entry == NULL) {
+		spin_unlock(&table->ht_lock);
+		return;
+	}
+
+	/*
+	 * All keys associated with this pid must be linked off of the
+	 * PID_KEY entry.  They are removed from the hash table and
+	 * linked in to a private working list to be destroyed.
+	 */
+
+	while (!list_empty(&pid_entry->he_pid_list)) {
+		entry = list_entry(pid_entry->he_pid_list.next,
+		    tsd_hash_entry_t, he_pid_list);
+		ASSERT3U(pid_entry->he_pid, ==, entry->he_pid);
+
+		hash = hash_long((ulong_t)entry->he_key *
+		    (ulong_t)entry->he_pid, table->ht_bits);
+		entry_bin = &table->ht_bins[hash];
+
+		spin_lock(&entry_bin->hb_lock);
+		tsd_hash_del(table, entry);
+		hlist_add_head(&entry->he_list, &work);
+		spin_unlock(&entry_bin->hb_lock);
+	}
+
+	hash = hash_long((ulong_t)pid_entry->he_key *
+	    (ulong_t)pid_entry->he_pid, table->ht_bits);
+	pid_entry_bin = &table->ht_bins[hash];
+
+	spin_lock(&pid_entry_bin->hb_lock);
+	tsd_hash_del(table, pid_entry);
+	hlist_add_head(&pid_entry->he_list, &work);
+	spin_unlock(&pid_entry_bin->hb_lock);
+	spin_unlock(&table->ht_lock);
+
+	tsd_hash_dtor(&work);
+}
+EXPORT_SYMBOL(tsd_exit);
+
+int
+spl_tsd_init(void)
+{
+	tsd_hash_table = tsd_hash_table_init(TSD_HASH_TABLE_BITS_DEFAULT);
+	if (tsd_hash_table == NULL)
+		return (1);
+
+	return (0);
+}
+
+void
+spl_tsd_fini(void)
+{
+	tsd_hash_table_fini(tsd_hash_table);
+	tsd_hash_table = NULL;
+}
diff --git a/module/spl/spl-vmem.c b/module/spl/spl-vmem.c
new file mode 100644
index 000000000..e1a84a911
--- /dev/null
+++ b/module/spl/spl-vmem.c
@@ -0,0 +1,135 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/debug.h>
+#include <sys/vmem.h>
+#include <sys/kmem_cache.h>
+#include <sys/shrinker.h>
+#include <linux/module.h>
+
+vmem_t *heap_arena = NULL;
+EXPORT_SYMBOL(heap_arena);
+
+vmem_t *zio_alloc_arena = NULL;
+EXPORT_SYMBOL(zio_alloc_arena);
+
+vmem_t *zio_arena = NULL;
+EXPORT_SYMBOL(zio_arena);
+
+#define	VMEM_FLOOR_SIZE		(4 * 1024 * 1024)	/* 4MB floor */
+
+/*
+ * Return approximate virtual memory usage based on these assumptions:
+ *
+ * 1) The major SPL consumer of virtual memory is the kmem cache.
+ * 2) Memory allocated with vmem_alloc() is short lived and can be ignored.
+ * 3) Allow a 4MB floor as a generous pad given normal consumption.
+ * 4) The spl_kmem_cache_sem only contends with cache create/destroy.
+ */
+size_t
+vmem_size(vmem_t *vmp, int typemask)
+{
+	spl_kmem_cache_t *skc;
+	size_t alloc = VMEM_FLOOR_SIZE;
+
+	if ((typemask & VMEM_ALLOC) && (typemask & VMEM_FREE))
+		return (VMALLOC_TOTAL);
+
+
+	down_read(&spl_kmem_cache_sem);
+	list_for_each_entry(skc, &spl_kmem_cache_list, skc_list) {
+		if (skc->skc_flags & KMC_VMEM)
+			alloc += skc->skc_slab_size * skc->skc_slab_total;
+	}
+	up_read(&spl_kmem_cache_sem);
+
+	if (typemask & VMEM_ALLOC)
+		return (MIN(alloc, VMALLOC_TOTAL));
+	else if (typemask & VMEM_FREE)
+		return (MAX(VMALLOC_TOTAL - alloc, 0));
+	else
+		return (0);
+}
+EXPORT_SYMBOL(vmem_size);
+
+/*
+ * Public vmem_alloc(), vmem_zalloc() and vmem_free() interfaces.
+ */
+void *
+spl_vmem_alloc(size_t size, int flags, const char *func, int line)
+{
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+
+	flags |= KM_VMEM;
+
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
+#else
+	return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
+#endif
+}
+EXPORT_SYMBOL(spl_vmem_alloc);
+
+void *
+spl_vmem_zalloc(size_t size, int flags, const char *func, int line)
+{
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+
+	flags |= (KM_VMEM | KM_ZERO);
+
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
+#else
+	return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
+#endif
+}
+EXPORT_SYMBOL(spl_vmem_zalloc);
+
+void
+spl_vmem_free(const void *buf, size_t size)
+{
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_free_impl(buf, size));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_free_debug(buf, size));
+#else
+	return (spl_kmem_free_track(buf, size));
+#endif
+}
+EXPORT_SYMBOL(spl_vmem_free);
+
+int
+spl_vmem_init(void)
+{
+	return (0);
+}
+
+void
+spl_vmem_fini(void)
+{
+}
diff --git a/module/spl/spl-vnode.c b/module/spl/spl-vnode.c
new file mode 100644
index 000000000..28ce21276
--- /dev/null
+++ b/module/spl/spl-vnode.c
@@ -0,0 +1,779 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) Vnode Implementation.
+ */
+
+#include <sys/cred.h>
+#include <sys/vnode.h>
+#include <sys/kmem_cache.h>
+#include <linux/falloc.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#ifdef HAVE_FDTABLE_HEADER
+#include <linux/fdtable.h>
+#endif
+
+vnode_t *rootdir = (vnode_t *)0xabcd1234;
+EXPORT_SYMBOL(rootdir);
+
+static spl_kmem_cache_t *vn_cache;
+static spl_kmem_cache_t *vn_file_cache;
+
+static DEFINE_SPINLOCK(vn_file_lock);
+static LIST_HEAD(vn_file_list);
+
+static int
+spl_filp_fallocate(struct file *fp, int mode, loff_t offset, loff_t len)
+{
+	int error = -EOPNOTSUPP;
+
+#ifdef HAVE_FILE_FALLOCATE
+	if (fp->f_op->fallocate)
+		error = fp->f_op->fallocate(fp, mode, offset, len);
+#else
+#ifdef HAVE_INODE_FALLOCATE
+	if (fp->f_dentry && fp->f_dentry->d_inode &&
+	    fp->f_dentry->d_inode->i_op->fallocate)
+		error = fp->f_dentry->d_inode->i_op->fallocate(
+		    fp->f_dentry->d_inode, mode, offset, len);
+#endif /* HAVE_INODE_FALLOCATE */
+#endif /* HAVE_FILE_FALLOCATE */
+
+	return (error);
+}
+
+static int
+spl_filp_fsync(struct file *fp, int sync)
+{
+#ifdef HAVE_2ARGS_VFS_FSYNC
+	return (vfs_fsync(fp, sync));
+#else
+	return (vfs_fsync(fp, (fp)->f_dentry, sync));
+#endif /* HAVE_2ARGS_VFS_FSYNC */
+}
+
+static ssize_t
+spl_kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
+{
+#if defined(HAVE_KERNEL_WRITE_PPOS)
+	return (kernel_write(file, buf, count, pos));
+#else
+	mm_segment_t saved_fs;
+	ssize_t ret;
+
+	saved_fs = get_fs();
+	set_fs(get_ds());
+
+	ret = vfs_write(file, (__force const char __user *)buf, count, pos);
+
+	set_fs(saved_fs);
+
+	return (ret);
+#endif
+}
+
+static ssize_t
+spl_kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
+{
+#if defined(HAVE_KERNEL_READ_PPOS)
+	return (kernel_read(file, buf, count, pos));
+#else
+	mm_segment_t saved_fs;
+	ssize_t ret;
+
+	saved_fs = get_fs();
+	set_fs(get_ds());
+
+	ret = vfs_read(file, (void __user *)buf, count, pos);
+
+	set_fs(saved_fs);
+
+	return (ret);
+#endif
+}
+
+vtype_t
+vn_mode_to_vtype(mode_t mode)
+{
+	if (S_ISREG(mode))
+		return (VREG);
+
+	if (S_ISDIR(mode))
+		return (VDIR);
+
+	if (S_ISCHR(mode))
+		return (VCHR);
+
+	if (S_ISBLK(mode))
+		return (VBLK);
+
+	if (S_ISFIFO(mode))
+		return (VFIFO);
+
+	if (S_ISLNK(mode))
+		return (VLNK);
+
+	if (S_ISSOCK(mode))
+		return (VSOCK);
+
+	return (VNON);
+} /* vn_mode_to_vtype() */
+EXPORT_SYMBOL(vn_mode_to_vtype);
+
+mode_t
+vn_vtype_to_mode(vtype_t vtype)
+{
+	if (vtype == VREG)
+		return (S_IFREG);
+
+	if (vtype == VDIR)
+		return (S_IFDIR);
+
+	if (vtype == VCHR)
+		return (S_IFCHR);
+
+	if (vtype == VBLK)
+		return (S_IFBLK);
+
+	if (vtype == VFIFO)
+		return (S_IFIFO);
+
+	if (vtype == VLNK)
+		return (S_IFLNK);
+
+	if (vtype == VSOCK)
+		return (S_IFSOCK);
+
+	return (VNON);
+} /* vn_vtype_to_mode() */
+EXPORT_SYMBOL(vn_vtype_to_mode);
+
+vnode_t *
+vn_alloc(int flag)
+{
+	vnode_t *vp;
+
+	vp = kmem_cache_alloc(vn_cache, flag);
+	if (vp != NULL) {
+		vp->v_file = NULL;
+		vp->v_type = 0;
+	}
+
+	return (vp);
+} /* vn_alloc() */
+EXPORT_SYMBOL(vn_alloc);
+
+void
+vn_free(vnode_t *vp)
+{
+	kmem_cache_free(vn_cache, vp);
+} /* vn_free() */
+EXPORT_SYMBOL(vn_free);
+
+int
+vn_open(const char *path, uio_seg_t seg, int flags, int mode, vnode_t **vpp,
+    int x1, void *x2)
+{
+	struct file *fp;
+	struct kstat stat;
+	int rc, saved_umask = 0;
+	gfp_t saved_gfp;
+	vnode_t *vp;
+
+	ASSERT(flags & (FWRITE | FREAD));
+	ASSERT(seg == UIO_SYSSPACE);
+	ASSERT(vpp);
+	*vpp = NULL;
+
+	if (!(flags & FCREAT) && (flags & FWRITE))
+		flags |= FEXCL;
+
+	/*
+	 * Note for filp_open() the two low bits must be remapped to mean:
+	 * 01 - read-only  -> 00 read-only
+	 * 10 - write-only -> 01 write-only
+	 * 11 - read-write -> 10 read-write
+	 */
+	flags--;
+
+	if (flags & FCREAT)
+		saved_umask = xchg(&current->fs->umask, 0);
+
+	fp = filp_open(path, flags, mode);
+
+	if (flags & FCREAT)
+		(void) xchg(&current->fs->umask, saved_umask);
+
+	if (IS_ERR(fp))
+		return (-PTR_ERR(fp));
+
+#if defined(HAVE_4ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&fp->f_path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
+#elif defined(HAVE_2ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&fp->f_path, &stat);
+#else
+	rc = vfs_getattr(fp->f_path.mnt, fp->f_dentry, &stat);
+#endif
+	if (rc) {
+		filp_close(fp, 0);
+		return (-rc);
+	}
+
+	vp = vn_alloc(KM_SLEEP);
+	if (!vp) {
+		filp_close(fp, 0);
+		return (ENOMEM);
+	}
+
+	saved_gfp = mapping_gfp_mask(fp->f_mapping);
+	mapping_set_gfp_mask(fp->f_mapping, saved_gfp & ~(__GFP_IO|__GFP_FS));
+
+	mutex_enter(&vp->v_lock);
+	vp->v_type = vn_mode_to_vtype(stat.mode);
+	vp->v_file = fp;
+	vp->v_gfp_mask = saved_gfp;
+	*vpp = vp;
+	mutex_exit(&vp->v_lock);
+
+	return (0);
+} /* vn_open() */
+EXPORT_SYMBOL(vn_open);
+
+int
+vn_openat(const char *path, uio_seg_t seg, int flags, int mode,
+    vnode_t **vpp, int x1, void *x2, vnode_t *vp, int fd)
+{
+	char *realpath;
+	int len, rc;
+
+	ASSERT(vp == rootdir);
+
+	len = strlen(path) + 2;
+	realpath = kmalloc(len, kmem_flags_convert(KM_SLEEP));
+	if (!realpath)
+		return (ENOMEM);
+
+	(void) snprintf(realpath, len, "/%s", path);
+	rc = vn_open(realpath, seg, flags, mode, vpp, x1, x2);
+	kfree(realpath);
+
+	return (rc);
+} /* vn_openat() */
+EXPORT_SYMBOL(vn_openat);
+
+int
+vn_rdwr(uio_rw_t uio, vnode_t *vp, void *addr, ssize_t len, offset_t off,
+    uio_seg_t seg, int ioflag, rlim64_t x2, void *x3, ssize_t *residp)
+{
+	struct file *fp = vp->v_file;
+	loff_t offset = off;
+	int rc;
+
+	ASSERT(uio == UIO_WRITE || uio == UIO_READ);
+	ASSERT(seg == UIO_SYSSPACE);
+	ASSERT((ioflag & ~FAPPEND) == 0);
+
+	if (ioflag & FAPPEND)
+		offset = fp->f_pos;
+
+	if (uio & UIO_WRITE)
+		rc = spl_kernel_write(fp, addr, len, &offset);
+	else
+		rc = spl_kernel_read(fp, addr, len, &offset);
+
+	fp->f_pos = offset;
+
+	if (rc < 0)
+		return (-rc);
+
+	if (residp) {
+		*residp = len - rc;
+	} else {
+		if (rc != len)
+			return (EIO);
+	}
+
+	return (0);
+} /* vn_rdwr() */
+EXPORT_SYMBOL(vn_rdwr);
+
+int
+vn_close(vnode_t *vp, int flags, int x1, int x2, void *x3, void *x4)
+{
+	int rc;
+
+	ASSERT(vp);
+	ASSERT(vp->v_file);
+
+	mapping_set_gfp_mask(vp->v_file->f_mapping, vp->v_gfp_mask);
+	rc = filp_close(vp->v_file, 0);
+	vn_free(vp);
+
+	return (-rc);
+} /* vn_close() */
+EXPORT_SYMBOL(vn_close);
+
+/*
+ * vn_seek() does not actually seek it only performs bounds checking on the
+ * proposed seek.  We perform minimal checking and allow vn_rdwr() to catch
+ * anything more serious.
+ */
+int
+vn_seek(vnode_t *vp, offset_t ooff, offset_t *noffp, void *ct)
+{
+	return ((*noffp < 0 || *noffp > MAXOFFSET_T) ? EINVAL : 0);
+}
+EXPORT_SYMBOL(vn_seek);
+
+int
+vn_getattr(vnode_t *vp, vattr_t *vap, int flags, void *x3, void *x4)
+{
+	struct file *fp;
+	struct kstat stat;
+	int rc;
+
+	ASSERT(vp);
+	ASSERT(vp->v_file);
+	ASSERT(vap);
+
+	fp = vp->v_file;
+
+#if defined(HAVE_4ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&fp->f_path, &stat, STATX_BASIC_STATS,
+	    AT_STATX_SYNC_AS_STAT);
+#elif defined(HAVE_2ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&fp->f_path, &stat);
+#else
+	rc = vfs_getattr(fp->f_path.mnt, fp->f_dentry, &stat);
+#endif
+	if (rc)
+		return (-rc);
+
+	vap->va_type	= vn_mode_to_vtype(stat.mode);
+	vap->va_mode	= stat.mode;
+	vap->va_uid	= KUID_TO_SUID(stat.uid);
+	vap->va_gid	= KGID_TO_SGID(stat.gid);
+	vap->va_fsid	= 0;
+	vap->va_nodeid	= stat.ino;
+	vap->va_nlink	= stat.nlink;
+	vap->va_size	= stat.size;
+	vap->va_blksize	= stat.blksize;
+	vap->va_atime	= stat.atime;
+	vap->va_mtime	= stat.mtime;
+	vap->va_ctime	= stat.ctime;
+	vap->va_rdev	= stat.rdev;
+	vap->va_nblocks	= stat.blocks;
+
+	return (0);
+}
+EXPORT_SYMBOL(vn_getattr);
+
+int
+vn_fsync(vnode_t *vp, int flags, void *x3, void *x4)
+{
+	int datasync = 0;
+	int error;
+	int fstrans;
+
+	ASSERT(vp);
+	ASSERT(vp->v_file);
+
+	if (flags & FDSYNC)
+		datasync = 1;
+
+	/*
+	 * May enter XFS which generates a warning when PF_FSTRANS is set.
+	 * To avoid this the flag is cleared over vfs_sync() and then reset.
+	 */
+	fstrans = __spl_pf_fstrans_check();
+	if (fstrans)
+		current->flags &= ~(__SPL_PF_FSTRANS);
+
+	error = -spl_filp_fsync(vp->v_file, datasync);
+	if (fstrans)
+		current->flags |= __SPL_PF_FSTRANS;
+
+	return (error);
+} /* vn_fsync() */
+EXPORT_SYMBOL(vn_fsync);
+
+int vn_space(vnode_t *vp, int cmd, struct flock *bfp, int flag,
+    offset_t offset, void *x6, void *x7)
+{
+	int error = EOPNOTSUPP;
+#ifdef FALLOC_FL_PUNCH_HOLE
+	int fstrans;
+#endif
+
+	if (cmd != F_FREESP || bfp->l_whence != 0)
+		return (EOPNOTSUPP);
+
+	ASSERT(vp);
+	ASSERT(vp->v_file);
+	ASSERT(bfp->l_start >= 0 && bfp->l_len > 0);
+
+#ifdef FALLOC_FL_PUNCH_HOLE
+	/*
+	 * May enter XFS which generates a warning when PF_FSTRANS is set.
+	 * To avoid this the flag is cleared over vfs_sync() and then reset.
+	 */
+	fstrans = __spl_pf_fstrans_check();
+	if (fstrans)
+		current->flags &= ~(__SPL_PF_FSTRANS);
+
+	/*
+	 * When supported by the underlying file system preferentially
+	 * use the fallocate() callback to preallocate the space.
+	 */
+	error = -spl_filp_fallocate(vp->v_file,
+	    FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
+	    bfp->l_start, bfp->l_len);
+
+	if (fstrans)
+		current->flags |= __SPL_PF_FSTRANS;
+
+	if (error == 0)
+		return (0);
+#endif
+
+#ifdef HAVE_INODE_TRUNCATE_RANGE
+	if (vp->v_file->f_dentry && vp->v_file->f_dentry->d_inode &&
+	    vp->v_file->f_dentry->d_inode->i_op &&
+	    vp->v_file->f_dentry->d_inode->i_op->truncate_range) {
+		off_t end = bfp->l_start + bfp->l_len;
+		/*
+		 * Judging from the code in shmem_truncate_range(),
+		 * it seems the kernel expects the end offset to be
+		 * inclusive and aligned to the end of a page.
+		 */
+		if (end % PAGE_SIZE != 0) {
+			end &= ~(off_t)(PAGE_SIZE - 1);
+			if (end <= bfp->l_start)
+				return (0);
+		}
+		--end;
+
+		vp->v_file->f_dentry->d_inode->i_op->truncate_range(
+		    vp->v_file->f_dentry->d_inode, bfp->l_start, end);
+
+		return (0);
+	}
+#endif
+
+	return (error);
+}
+EXPORT_SYMBOL(vn_space);
+
+/* Function must be called while holding the vn_file_lock */
+static file_t *
+file_find(int fd, struct task_struct *task)
+{
+	file_t *fp;
+
+	list_for_each_entry(fp, &vn_file_list,  f_list) {
+		if (fd == fp->f_fd && fp->f_task == task) {
+			ASSERT(atomic_read(&fp->f_ref) != 0);
+			return (fp);
+		}
+	}
+
+	return (NULL);
+} /* file_find() */
+
+file_t *
+vn_getf(int fd)
+{
+	struct kstat stat;
+	struct file *lfp;
+	file_t *fp;
+	vnode_t *vp;
+	int rc = 0;
+
+	if (fd < 0)
+		return (NULL);
+
+	/* Already open just take an extra reference */
+	spin_lock(&vn_file_lock);
+
+	fp = file_find(fd, current);
+	if (fp) {
+		lfp = fget(fd);
+		fput(fp->f_file);
+		/*
+		 * areleasef() can cause us to see a stale reference when
+		 * userspace has reused a file descriptor before areleasef()
+		 * has run. fput() the stale reference and replace it. We
+		 * retain the original reference count such that the concurrent
+		 * areleasef() will decrement its reference and terminate.
+		 */
+		if (lfp != fp->f_file) {
+			fp->f_file = lfp;
+			fp->f_vnode->v_file = lfp;
+		}
+		atomic_inc(&fp->f_ref);
+		spin_unlock(&vn_file_lock);
+		return (fp);
+	}
+
+	spin_unlock(&vn_file_lock);
+
+	/* File was not yet opened create the object and setup */
+	fp = kmem_cache_alloc(vn_file_cache, KM_SLEEP);
+	if (fp == NULL)
+		goto out;
+
+	mutex_enter(&fp->f_lock);
+
+	fp->f_fd = fd;
+	fp->f_task = current;
+	fp->f_offset = 0;
+	atomic_inc(&fp->f_ref);
+
+	lfp = fget(fd);
+	if (lfp == NULL)
+		goto out_mutex;
+
+	vp = vn_alloc(KM_SLEEP);
+	if (vp == NULL)
+		goto out_fget;
+
+#if defined(HAVE_4ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&lfp->f_path, &stat, STATX_TYPE,
+	    AT_STATX_SYNC_AS_STAT);
+#elif defined(HAVE_2ARGS_VFS_GETATTR)
+	rc = vfs_getattr(&lfp->f_path, &stat);
+#else
+	rc = vfs_getattr(lfp->f_path.mnt, lfp->f_dentry, &stat);
+#endif
+	if (rc)
+		goto out_vnode;
+
+	mutex_enter(&vp->v_lock);
+	vp->v_type = vn_mode_to_vtype(stat.mode);
+	vp->v_file = lfp;
+	mutex_exit(&vp->v_lock);
+
+	fp->f_vnode = vp;
+	fp->f_file = lfp;
+
+	/* Put it on the tracking list */
+	spin_lock(&vn_file_lock);
+	list_add(&fp->f_list, &vn_file_list);
+	spin_unlock(&vn_file_lock);
+
+	mutex_exit(&fp->f_lock);
+	return (fp);
+
+out_vnode:
+	vn_free(vp);
+out_fget:
+	fput(lfp);
+out_mutex:
+	mutex_exit(&fp->f_lock);
+	kmem_cache_free(vn_file_cache, fp);
+out:
+	return (NULL);
+} /* getf() */
+EXPORT_SYMBOL(getf);
+
+static void releasef_locked(file_t *fp)
+{
+	ASSERT(fp->f_file);
+	ASSERT(fp->f_vnode);
+
+	/* Unlinked from list, no refs, safe to free outside mutex */
+	fput(fp->f_file);
+	vn_free(fp->f_vnode);
+
+	kmem_cache_free(vn_file_cache, fp);
+}
+
+void
+vn_releasef(int fd)
+{
+	areleasef(fd, P_FINFO(current));
+}
+EXPORT_SYMBOL(releasef);
+
+void
+vn_areleasef(int fd, uf_info_t *fip)
+{
+	file_t *fp;
+	struct task_struct *task = (struct task_struct *)fip;
+
+	if (fd < 0)
+		return;
+
+	spin_lock(&vn_file_lock);
+	fp = file_find(fd, task);
+	if (fp) {
+		atomic_dec(&fp->f_ref);
+		if (atomic_read(&fp->f_ref) > 0) {
+			spin_unlock(&vn_file_lock);
+			return;
+		}
+
+		list_del(&fp->f_list);
+		releasef_locked(fp);
+	}
+	spin_unlock(&vn_file_lock);
+} /* releasef() */
+EXPORT_SYMBOL(areleasef);
+
+
+static void
+#ifdef HAVE_SET_FS_PWD_WITH_CONST
+vn_set_fs_pwd(struct fs_struct *fs, const struct path *path)
+#else
+vn_set_fs_pwd(struct fs_struct *fs, struct path *path)
+#endif /* HAVE_SET_FS_PWD_WITH_CONST */
+{
+	struct path old_pwd;
+
+#ifdef HAVE_FS_STRUCT_SPINLOCK
+	spin_lock(&fs->lock);
+	old_pwd = fs->pwd;
+	fs->pwd = *path;
+	path_get(path);
+	spin_unlock(&fs->lock);
+#else
+	write_lock(&fs->lock);
+	old_pwd = fs->pwd;
+	fs->pwd = *path;
+	path_get(path);
+	write_unlock(&fs->lock);
+#endif /* HAVE_FS_STRUCT_SPINLOCK */
+
+	if (old_pwd.dentry)
+		path_put(&old_pwd);
+}
+
+int
+vn_set_pwd(const char *filename)
+{
+	struct path path;
+	mm_segment_t saved_fs;
+	int rc;
+
+	/*
+	 * user_path_dir() and __user_walk() both expect 'filename' to be
+	 * a user space address so we must briefly increase the data segment
+	 * size to ensure strncpy_from_user() does not fail with -EFAULT.
+	 */
+	saved_fs = get_fs();
+	set_fs(get_ds());
+
+	rc = user_path_dir(filename, &path);
+	if (rc)
+		goto out;
+
+	rc = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
+	if (rc)
+		goto dput_and_out;
+
+	vn_set_fs_pwd(current->fs, &path);
+
+dput_and_out:
+	path_put(&path);
+out:
+	set_fs(saved_fs);
+
+	return (-rc);
+} /* vn_set_pwd() */
+EXPORT_SYMBOL(vn_set_pwd);
+
+static int
+vn_cache_constructor(void *buf, void *cdrarg, int kmflags)
+{
+	struct vnode *vp = buf;
+
+	mutex_init(&vp->v_lock, NULL, MUTEX_DEFAULT, NULL);
+
+	return (0);
+} /* vn_cache_constructor() */
+
+static void
+vn_cache_destructor(void *buf, void *cdrarg)
+{
+	struct vnode *vp = buf;
+
+	mutex_destroy(&vp->v_lock);
+} /* vn_cache_destructor() */
+
+static int
+vn_file_cache_constructor(void *buf, void *cdrarg, int kmflags)
+{
+	file_t *fp = buf;
+
+	atomic_set(&fp->f_ref, 0);
+	mutex_init(&fp->f_lock, NULL, MUTEX_DEFAULT, NULL);
+	INIT_LIST_HEAD(&fp->f_list);
+
+	return (0);
+} /* vn_file_cache_constructor() */
+
+static void
+vn_file_cache_destructor(void *buf, void *cdrarg)
+{
+	file_t *fp = buf;
+
+	mutex_destroy(&fp->f_lock);
+} /* vn_file_cache_destructor() */
+
+int
+spl_vn_init(void)
+{
+	vn_cache = kmem_cache_create("spl_vn_cache",
+	    sizeof (struct vnode), 64, vn_cache_constructor,
+	    vn_cache_destructor, NULL, NULL, NULL, 0);
+
+	vn_file_cache = kmem_cache_create("spl_vn_file_cache",
+	    sizeof (file_t), 64, vn_file_cache_constructor,
+	    vn_file_cache_destructor, NULL, NULL, NULL, 0);
+
+	return (0);
+} /* spl_vn_init() */
+
+void
+spl_vn_fini(void)
+{
+	file_t *fp, *next_fp;
+	int leaked = 0;
+
+	spin_lock(&vn_file_lock);
+
+	list_for_each_entry_safe(fp, next_fp, &vn_file_list,  f_list) {
+		list_del(&fp->f_list);
+		releasef_locked(fp);
+		leaked++;
+	}
+
+	spin_unlock(&vn_file_lock);
+
+	if (leaked > 0)
+		printk(KERN_WARNING "WARNING: %d vnode files leaked\n", leaked);
+
+	kmem_cache_destroy(vn_file_cache);
+	kmem_cache_destroy(vn_cache);
+} /* spl_vn_fini() */
diff --git a/module/spl/spl-xdr.c b/module/spl/spl-xdr.c
new file mode 100644
index 000000000..2cc3e2a03
--- /dev/null
+++ b/module/spl/spl-xdr.c
@@ -0,0 +1,515 @@
+/*
+ *  Copyright (c) 2008-2010 Sun Microsystems, Inc.
+ *  Written by Ricardo Correia <[email protected]>
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Solaris Porting Layer (SPL) XDR Implementation.
+ */
+
+#include <linux/string.h>
+#include <sys/kmem.h>
+#include <sys/debug.h>
+#include <sys/types.h>
+#include <sys/sysmacros.h>
+#include <rpc/xdr.h>
+
+/*
+ * SPL's XDR mem implementation.
+ *
+ * This is used by libnvpair to serialize/deserialize the name-value pair data
+ * structures into byte arrays in a well-defined and portable manner.
+ *
+ * These data structures are used by the DMU/ZFS to flexibly manipulate various
+ * information in memory and later serialize it/deserialize it to disk.
+ * Examples of usages include the pool configuration, lists of pool and dataset
+ * properties, etc.
+ *
+ * Reference documentation for the XDR representation and XDR operations can be
+ * found in RFC 1832 and xdr(3), respectively.
+ *
+ * ===  Implementation shortcomings ===
+ *
+ * It is assumed that the following C types have the following sizes:
+ *
+ * char/unsigned char:      1 byte
+ * short/unsigned short:    2 bytes
+ * int/unsigned int:        4 bytes
+ * longlong_t/u_longlong_t: 8 bytes
+ *
+ * The C standard allows these types to be larger (and in the case of ints,
+ * shorter), so if that is the case on some compiler/architecture, the build
+ * will fail (on purpose).
+ *
+ * If someone wants to fix the code to work properly on such environments, then:
+ *
+ * 1) Preconditions should be added to xdrmem_enc functions to make sure the
+ *    caller doesn't pass arguments which exceed the expected range.
+ * 2) Functions which take signed integers should be changed to properly do
+ *    sign extension.
+ * 3) For ints with less than 32 bits, well.. I suspect you'll have bigger
+ *    problems than this implementation.
+ *
+ * It is also assumed that:
+ *
+ * 1) Chars have 8 bits.
+ * 2) We can always do 32-bit-aligned int memory accesses and byte-aligned
+ *    memcpy, memset and memcmp.
+ * 3) Arrays passed to xdr_array() are packed and the compiler/architecture
+ *    supports element-sized-aligned memory accesses.
+ * 4) Negative integers are natively stored in two's complement binary
+ *    representation.
+ *
+ * No checks are done for the 4 assumptions above, though.
+ *
+ * === Caller expectations ===
+ *
+ * Existing documentation does not describe the semantics of XDR operations very
+ * well.  Therefore, some assumptions about failure semantics will be made and
+ * will be described below:
+ *
+ * 1) If any encoding operation fails (e.g., due to lack of buffer space), the
+ * the stream should be considered valid only up to the encoding operation
+ * previous to the one that first failed. However, the stream size as returned
+ * by xdr_control() cannot be considered to be strictly correct (it may be
+ * bigger).
+ *
+ * Putting it another way, if there is an encoding failure it's undefined
+ * whether anything is added to the stream in that operation and therefore
+ * neither xdr_control() nor future encoding operations on the same stream can
+ * be relied upon to produce correct results.
+ *
+ * 2) If a decoding operation fails, it's undefined whether anything will be
+ * decoded into passed buffers/pointers during that operation, or what the
+ * values on those buffers will look like.
+ *
+ * Future decoding operations on the same stream will also have similar
+ * undefined behavior.
+ *
+ * 3) When the first decoding operation fails it is OK to trust the results of
+ * previous decoding operations on the same stream, as long as the caller
+ * expects a failure to be possible (e.g. due to end-of-stream).
+ *
+ * However, this is highly discouraged because the caller should know the
+ * stream size and should be coded to expect any decoding failure to be data
+ * corruption due to hardware, accidental or even malicious causes, which should
+ * be handled gracefully in all cases.
+ *
+ * In very rare situations where there are strong reasons to believe the data
+ * can be trusted to be valid and non-tampered with, then the caller may assume
+ * a decoding failure to be a bug (e.g. due to mismatched data types) and may
+ * fail non-gracefully.
+ *
+ * 4) Non-zero padding bytes will cause the decoding operation to fail.
+ *
+ * 5) Zero bytes on string types will also cause the decoding operation to fail.
+ *
+ * 6) It is assumed that either the pointer to the stream buffer given by the
+ * caller is 32-bit aligned or the architecture supports non-32-bit-aligned int
+ * memory accesses.
+ *
+ * 7) The stream buffer and encoding/decoding buffers/ptrs should not overlap.
+ *
+ * 8) If a caller passes pointers to non-kernel memory (e.g., pointers to user
+ * space or MMIO space), the computer may explode.
+ */
+
+static struct xdr_ops xdrmem_encode_ops;
+static struct xdr_ops xdrmem_decode_ops;
+
+typedef int bool_t;
+
+void
+xdrmem_create(XDR *xdrs, const caddr_t addr, const uint_t size,
+    const enum xdr_op op)
+{
+	switch (op) {
+		case XDR_ENCODE:
+			xdrs->x_ops = &xdrmem_encode_ops;
+			break;
+		case XDR_DECODE:
+			xdrs->x_ops = &xdrmem_decode_ops;
+			break;
+		default:
+			xdrs->x_ops = NULL; /* Let the caller know we failed */
+			return;
+	}
+
+	xdrs->x_op = op;
+	xdrs->x_addr = addr;
+	xdrs->x_addr_end = addr + size;
+
+	if (xdrs->x_addr_end < xdrs->x_addr) {
+		xdrs->x_ops = NULL;
+	}
+}
+EXPORT_SYMBOL(xdrmem_create);
+
+static bool_t
+xdrmem_control(XDR *xdrs, int req, void *info)
+{
+	struct xdr_bytesrec *rec = (struct xdr_bytesrec *)info;
+
+	if (req != XDR_GET_BYTES_AVAIL)
+		return (FALSE);
+
+	rec->xc_is_last_record = TRUE; /* always TRUE in xdrmem streams */
+	rec->xc_num_avail = xdrs->x_addr_end - xdrs->x_addr;
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_enc_bytes(XDR *xdrs, caddr_t cp, const uint_t cnt)
+{
+	uint_t size = roundup(cnt, 4);
+	uint_t pad;
+
+	if (size < cnt)
+		return (FALSE); /* Integer overflow */
+
+	if (xdrs->x_addr > xdrs->x_addr_end)
+		return (FALSE);
+
+	if (xdrs->x_addr_end - xdrs->x_addr < size)
+		return (FALSE);
+
+	memcpy(xdrs->x_addr, cp, cnt);
+
+	xdrs->x_addr += cnt;
+
+	pad = size - cnt;
+	if (pad > 0) {
+		memset(xdrs->x_addr, 0, pad);
+		xdrs->x_addr += pad;
+	}
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_dec_bytes(XDR *xdrs, caddr_t cp, const uint_t cnt)
+{
+	static uint32_t zero = 0;
+	uint_t size = roundup(cnt, 4);
+	uint_t pad;
+
+	if (size < cnt)
+		return (FALSE); /* Integer overflow */
+
+	if (xdrs->x_addr > xdrs->x_addr_end)
+		return (FALSE);
+
+	if (xdrs->x_addr_end - xdrs->x_addr < size)
+		return (FALSE);
+
+	memcpy(cp, xdrs->x_addr, cnt);
+	xdrs->x_addr += cnt;
+
+	pad = size - cnt;
+	if (pad > 0) {
+		/* An inverted memchr() would be useful here... */
+		if (memcmp(&zero, xdrs->x_addr, pad) != 0)
+			return (FALSE);
+
+		xdrs->x_addr += pad;
+	}
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_enc_uint32(XDR *xdrs, uint32_t val)
+{
+	if (xdrs->x_addr + sizeof (uint32_t) > xdrs->x_addr_end)
+		return (FALSE);
+
+	*((uint32_t *)xdrs->x_addr) = cpu_to_be32(val);
+
+	xdrs->x_addr += sizeof (uint32_t);
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_dec_uint32(XDR *xdrs, uint32_t *val)
+{
+	if (xdrs->x_addr + sizeof (uint32_t) > xdrs->x_addr_end)
+		return (FALSE);
+
+	*val = be32_to_cpu(*((uint32_t *)xdrs->x_addr));
+
+	xdrs->x_addr += sizeof (uint32_t);
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_enc_char(XDR *xdrs, char *cp)
+{
+	uint32_t val;
+
+	BUILD_BUG_ON(sizeof (char) != 1);
+	val = *((unsigned char *) cp);
+
+	return (xdrmem_enc_uint32(xdrs, val));
+}
+
+static bool_t
+xdrmem_dec_char(XDR *xdrs, char *cp)
+{
+	uint32_t val;
+
+	BUILD_BUG_ON(sizeof (char) != 1);
+
+	if (!xdrmem_dec_uint32(xdrs, &val))
+		return (FALSE);
+
+	/*
+	 * If any of the 3 other bytes are non-zero then val will be greater
+	 * than 0xff and we fail because according to the RFC, this block does
+	 * not have a char encoded in it.
+	 */
+	if (val > 0xff)
+		return (FALSE);
+
+	*((unsigned char *) cp) = val;
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_enc_ushort(XDR *xdrs, unsigned short *usp)
+{
+	BUILD_BUG_ON(sizeof (unsigned short) != 2);
+
+	return (xdrmem_enc_uint32(xdrs, *usp));
+}
+
+static bool_t
+xdrmem_dec_ushort(XDR *xdrs, unsigned short *usp)
+{
+	uint32_t val;
+
+	BUILD_BUG_ON(sizeof (unsigned short) != 2);
+
+	if (!xdrmem_dec_uint32(xdrs, &val))
+		return (FALSE);
+
+	/*
+	 * Short ints are not in the RFC, but we assume similar logic as in
+	 * xdrmem_dec_char().
+	 */
+	if (val > 0xffff)
+		return (FALSE);
+
+	*usp = val;
+
+	return (TRUE);
+}
+
+static bool_t
+xdrmem_enc_uint(XDR *xdrs, unsigned *up)
+{
+	BUILD_BUG_ON(sizeof (unsigned) != 4);
+
+	return (xdrmem_enc_uint32(xdrs, *up));
+}
+
+static bool_t
+xdrmem_dec_uint(XDR *xdrs, unsigned *up)
+{
+	BUILD_BUG_ON(sizeof (unsigned) != 4);
+
+	return (xdrmem_dec_uint32(xdrs, (uint32_t *)up));
+}
+
+static bool_t
+xdrmem_enc_ulonglong(XDR *xdrs, u_longlong_t *ullp)
+{
+	BUILD_BUG_ON(sizeof (u_longlong_t) != 8);
+
+	if (!xdrmem_enc_uint32(xdrs, *ullp >> 32))
+		return (FALSE);
+
+	return (xdrmem_enc_uint32(xdrs, *ullp & 0xffffffff));
+}
+
+static bool_t
+xdrmem_dec_ulonglong(XDR *xdrs, u_longlong_t *ullp)
+{
+	uint32_t low, high;
+
+	BUILD_BUG_ON(sizeof (u_longlong_t) != 8);
+
+	if (!xdrmem_dec_uint32(xdrs, &high))
+		return (FALSE);
+	if (!xdrmem_dec_uint32(xdrs, &low))
+		return (FALSE);
+
+	*ullp = ((u_longlong_t)high << 32) | low;
+
+	return (TRUE);
+}
+
+static bool_t
+xdr_enc_array(XDR *xdrs, caddr_t *arrp, uint_t *sizep, const uint_t maxsize,
+    const uint_t elsize, const xdrproc_t elproc)
+{
+	uint_t i;
+	caddr_t addr = *arrp;
+
+	if (*sizep > maxsize || *sizep > UINT_MAX / elsize)
+		return (FALSE);
+
+	if (!xdrmem_enc_uint(xdrs, sizep))
+		return (FALSE);
+
+	for (i = 0; i < *sizep; i++) {
+		if (!elproc(xdrs, addr))
+			return (FALSE);
+		addr += elsize;
+	}
+
+	return (TRUE);
+}
+
+static bool_t
+xdr_dec_array(XDR *xdrs, caddr_t *arrp, uint_t *sizep, const uint_t maxsize,
+    const uint_t elsize, const xdrproc_t elproc)
+{
+	uint_t i, size;
+	bool_t alloc = FALSE;
+	caddr_t addr;
+
+	if (!xdrmem_dec_uint(xdrs, sizep))
+		return (FALSE);
+
+	size = *sizep;
+
+	if (size > maxsize || size > UINT_MAX / elsize)
+		return (FALSE);
+
+	/*
+	 * The Solaris man page says: "If *arrp is NULL when decoding,
+	 * xdr_array() allocates memory and *arrp points to it".
+	 */
+	if (*arrp == NULL) {
+		BUILD_BUG_ON(sizeof (uint_t) > sizeof (size_t));
+
+		*arrp = kmem_alloc(size * elsize, KM_NOSLEEP);
+		if (*arrp == NULL)
+			return (FALSE);
+
+		alloc = TRUE;
+	}
+
+	addr = *arrp;
+
+	for (i = 0; i < size; i++) {
+		if (!elproc(xdrs, addr)) {
+			if (alloc)
+				kmem_free(*arrp, size * elsize);
+			return (FALSE);
+		}
+		addr += elsize;
+	}
+
+	return (TRUE);
+}
+
+static bool_t
+xdr_enc_string(XDR *xdrs, char **sp, const uint_t maxsize)
+{
+	size_t slen = strlen(*sp);
+	uint_t len;
+
+	if (slen > maxsize)
+		return (FALSE);
+
+	len = slen;
+
+	if (!xdrmem_enc_uint(xdrs, &len))
+		return (FALSE);
+
+	return (xdrmem_enc_bytes(xdrs, *sp, len));
+}
+
+static bool_t
+xdr_dec_string(XDR *xdrs, char **sp, const uint_t maxsize)
+{
+	uint_t size;
+	bool_t alloc = FALSE;
+
+	if (!xdrmem_dec_uint(xdrs, &size))
+		return (FALSE);
+
+	if (size > maxsize || size > UINT_MAX - 1)
+		return (FALSE);
+
+	/*
+	 * Solaris man page: "If *sp is NULL when decoding, xdr_string()
+	 * allocates memory and *sp points to it".
+	 */
+	if (*sp == NULL) {
+		BUILD_BUG_ON(sizeof (uint_t) > sizeof (size_t));
+
+		*sp = kmem_alloc(size + 1, KM_NOSLEEP);
+		if (*sp == NULL)
+			return (FALSE);
+
+		alloc = TRUE;
+	}
+
+	if (!xdrmem_dec_bytes(xdrs, *sp, size))
+		goto fail;
+
+	if (memchr(*sp, 0, size) != NULL)
+		goto fail;
+
+	(*sp)[size] = '\0';
+
+	return (TRUE);
+
+fail:
+	if (alloc)
+		kmem_free(*sp, size + 1);
+
+	return (FALSE);
+}
+
+static struct xdr_ops xdrmem_encode_ops = {
+	.xdr_control		= xdrmem_control,
+	.xdr_char		= xdrmem_enc_char,
+	.xdr_u_short		= xdrmem_enc_ushort,
+	.xdr_u_int		= xdrmem_enc_uint,
+	.xdr_u_longlong_t	= xdrmem_enc_ulonglong,
+	.xdr_opaque		= xdrmem_enc_bytes,
+	.xdr_string		= xdr_enc_string,
+	.xdr_array		= xdr_enc_array
+};
+
+static struct xdr_ops xdrmem_decode_ops = {
+	.xdr_control		= xdrmem_control,
+	.xdr_char		= xdrmem_dec_char,
+	.xdr_u_short		= xdrmem_dec_ushort,
+	.xdr_u_int		= xdrmem_dec_uint,
+	.xdr_u_longlong_t	= xdrmem_dec_ulonglong,
+	.xdr_opaque		= xdrmem_dec_bytes,
+	.xdr_string		= xdr_dec_string,
+	.xdr_array		= xdr_dec_array
+};
diff --git a/module/spl/spl-zlib.c b/module/spl/spl-zlib.c
new file mode 100644
index 000000000..229e6a44b
--- /dev/null
+++ b/module/spl/spl-zlib.c
@@ -0,0 +1,217 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <[email protected]>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ *  z_compress_level/z_uncompress are nearly identical copies of the
+ *  compress2/uncompress functions provided by the official zlib package
+ *  available at http://zlib.net/.  The only changes made we to slightly
+ *  adapt the functions called to match the linux kernel implementation
+ *  of zlib.  The full zlib license follows:
+ *
+ *  zlib.h -- interface of the 'zlib' general purpose compression library
+ *  version 1.2.5, April 19th, 2010
+ *
+ *  Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
+ *
+ *  This software is provided 'as-is', without any express or implied
+ *  warranty.  In no event will the authors be held liable for any damages
+ *  arising from the use of this software.
+ *
+ *  Permission is granted to anyone to use this software for any purpose,
+ *  including commercial applications, and to alter it and redistribute it
+ *  freely, subject to the following restrictions:
+ *
+ *  1. The origin of this software must not be misrepresented; you must not
+ *     claim that you wrote the original software. If you use this software
+ *     in a product, an acknowledgment in the product documentation would be
+ *     appreciated but is not required.
+ *  2. Altered source versions must be plainly marked as such, and must not be
+ *     misrepresented as being the original software.
+ *  3. This notice may not be removed or altered from any source distribution.
+ *
+ *  Jean-loup Gailly
+ *  Mark Adler
+ */
+
+
+#include <sys/kmem.h>
+#include <sys/kmem_cache.h>
+#include <sys/zmod.h>
+
+static spl_kmem_cache_t *zlib_workspace_cache;
+
+/*
+ * A kmem_cache is used for the zlib workspaces to avoid having to vmalloc
+ * and vfree for every call.  Using a kmem_cache also has the advantage
+ * that improves the odds that the memory used will be local to this cpu.
+ * To further improve things it might be wise to create a dedicated per-cpu
+ * workspace for use.  This would take some additional care because we then
+ * must disable preemption around the critical section, and verify that
+ * zlib_deflate* and zlib_inflate* never internally call schedule().
+ */
+static void *
+zlib_workspace_alloc(int flags)
+{
+	return (kmem_cache_alloc(zlib_workspace_cache, flags & ~(__GFP_FS)));
+}
+
+static void
+zlib_workspace_free(void *workspace)
+{
+	kmem_cache_free(zlib_workspace_cache, workspace);
+}
+
+/*
+ * Compresses the source buffer into the destination buffer. The level
+ * parameter has the same meaning as in deflateInit.  sourceLen is the byte
+ * length of the source buffer. Upon entry, destLen is the total size of the
+ * destination buffer, which must be at least 0.1% larger than sourceLen plus
+ * 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
+ *
+ * compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
+ * memory, Z_BUF_ERROR if there was not enough room in the output buffer,
+ * Z_STREAM_ERROR if the level parameter is invalid.
+ */
+int
+z_compress_level(void *dest, size_t *destLen, const void *source,
+    size_t sourceLen, int level)
+{
+	z_stream stream;
+	int err;
+
+	stream.next_in = (Byte *)source;
+	stream.avail_in = (uInt)sourceLen;
+	stream.next_out = dest;
+	stream.avail_out = (uInt)*destLen;
+
+	if ((size_t)stream.avail_out != *destLen)
+		return (Z_BUF_ERROR);
+
+	stream.workspace = zlib_workspace_alloc(KM_SLEEP);
+	if (!stream.workspace)
+		return (Z_MEM_ERROR);
+
+	err = zlib_deflateInit(&stream, level);
+	if (err != Z_OK) {
+		zlib_workspace_free(stream.workspace);
+		return (err);
+	}
+
+	err = zlib_deflate(&stream, Z_FINISH);
+	if (err != Z_STREAM_END) {
+		zlib_deflateEnd(&stream);
+		zlib_workspace_free(stream.workspace);
+		return (err == Z_OK ? Z_BUF_ERROR : err);
+	}
+	*destLen = stream.total_out;
+
+	err = zlib_deflateEnd(&stream);
+	zlib_workspace_free(stream.workspace);
+
+	return (err);
+}
+EXPORT_SYMBOL(z_compress_level);
+
+/*
+ * Decompresses the source buffer into the destination buffer.  sourceLen is
+ * the byte length of the source buffer. Upon entry, destLen is the total
+ * size of the destination buffer, which must be large enough to hold the
+ * entire uncompressed data. (The size of the uncompressed data must have
+ * been saved previously by the compressor and transmitted to the decompressor
+ * by some mechanism outside the scope of this compression library.)
+ * Upon exit, destLen is the actual size of the compressed buffer.
+ * This function can be used to decompress a whole file at once if the
+ * input file is mmap'ed.
+ *
+ * uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
+ * enough memory, Z_BUF_ERROR if there was not enough room in the output
+ * buffer, or Z_DATA_ERROR if the input data was corrupted.
+ */
+int
+z_uncompress(void *dest, size_t *destLen, const void *source, size_t sourceLen)
+{
+	z_stream stream;
+	int err;
+
+	stream.next_in = (Byte *)source;
+	stream.avail_in = (uInt)sourceLen;
+	stream.next_out = dest;
+	stream.avail_out = (uInt)*destLen;
+
+	if ((size_t)stream.avail_out != *destLen)
+		return (Z_BUF_ERROR);
+
+	stream.workspace = zlib_workspace_alloc(KM_SLEEP);
+	if (!stream.workspace)
+		return (Z_MEM_ERROR);
+
+	err = zlib_inflateInit(&stream);
+	if (err != Z_OK) {
+		zlib_workspace_free(stream.workspace);
+		return (err);
+	}
+
+	err = zlib_inflate(&stream, Z_FINISH);
+	if (err != Z_STREAM_END) {
+		zlib_inflateEnd(&stream);
+		zlib_workspace_free(stream.workspace);
+
+		if (err == Z_NEED_DICT ||
+		    (err == Z_BUF_ERROR && stream.avail_in == 0))
+			return (Z_DATA_ERROR);
+
+		return (err);
+	}
+	*destLen = stream.total_out;
+
+	err = zlib_inflateEnd(&stream);
+	zlib_workspace_free(stream.workspace);
+
+	return (err);
+}
+EXPORT_SYMBOL(z_uncompress);
+
+int
+spl_zlib_init(void)
+{
+	int size;
+
+	size = MAX(spl_zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
+	    zlib_inflate_workspacesize());
+
+	zlib_workspace_cache = kmem_cache_create(
+	    "spl_zlib_workspace_cache",
+	    size, 0, NULL, NULL, NULL, NULL, NULL,
+	    KMC_VMEM | KMC_NOEMERGENCY);
+	if (!zlib_workspace_cache)
+		return (1);
+
+	return (0);
+}
+
+void
+spl_zlib_fini(void)
+{
+	kmem_cache_destroy(zlib_workspace_cache);
+	zlib_workspace_cache = NULL;
+}