Reimplement rwlocks for Linux lock profiling/analysis.

It turns out that the previous rwlock implementation worked well but
did not integrate properly with the upstream kernel lock profiling/
analysis tools.  This is a major problem since it would be awfully
nice to be able to use the automatic lock checker and profiler.

The problem is that the upstream lock tools use the pre-processor
to create a lock class for each uniquely named locked.  Since the
rwsem was embedded in a wrapper structure the name was always the
same.  The effect was that we only ended up with one lock class for
the entire SPL which caused the lock dependency checker to flag
nearly everything as a possible deadlock.

The solution was to directly map a krwlock to a Linux rwsem using
a typedef there by eliminating the wrapper structure.  This was not
done initially because the rwsem implementation is specific to the arch.
To fully implement the Solaris krwlock API using only the provided rwsem
API is not possible.  It can only be done by directly accessing some of
the internal data member of the rwsem structure.

For example, the Linux API provides a different function for dropping
a reader vs writer lock.  Whereas the Solaris API uses the same function
and the caller does not pass in what type of lock it is.  This means to
properly drop the lock we need to determine if the lock is currently a
reader or writer lock.  Then we need to call the proper Linux API function.
Unfortunately, there is no provided API for this so we must extracted this
information directly from arch specific lock implementation.  This is
all do able, and what I did, but it does complicate things considerably.

The good news is that in addition to the profiling benefits of this
change.  We may see performance improvements due to slightly reduced
overhead when creating rwlocks and manipulating them.

The only function I was forced to sacrafice was rw_owner() because this
information is simply not stored anywhere in the rwsem.  Luckily this
appears not to be a commonly used function on Solaris, and it is my
understanding it is mainly used for debugging anyway.

In addition to the core rwlock changes, extensive updates were made to
the rwlock regression tests.  Each class of test was extended to provide
more API coverage and to be more rigerous in checking for misbehavior.

This is a pretty significant change and with that in mind I have been
careful to validate it on several platforms before committing.  The full
SPLAT regression test suite was run numberous times on all of the following
platforms.  This includes various kernels ranging from 2.6.16 to 2.6.29.

- SLES10   (ppc64)
- SLES11   (x86_64)
- CHAOS4.2 (x86_64)
- RHEL5.3  (x86_64)
- RHEL6    (x86_64)
- FC11     (x86_64)

4 files changed, 525 insertions, 885 deletions

diff --git a/module/spl/spl-generic.c b/module/spl/spl-generic.c
index b81dabc56..8e0ef9263 100644
--- a/module/spl/spl-generic.c
+++ b/module/spl/spl-generic.c
@@ -253,6 +253,22 @@ ddi_copyout(const void *from, void *to, size_t len, int flags)
 }
 EXPORT_SYMBOL(ddi_copyout);
 
+#ifndef HAVE_PUT_TASK_STRUCT
+/*
+ * This is only a stub function which should never be used.  The SPL should
+ * never be putting away the last reference on a task structure so this will
+ * not be called.  However, we still need to define it so the module does not
+ * have undefined symbol at load time.  That all said if this impossible
+ * thing does somehow happen SBUG() immediately so we know about it.
+ */
+void
+__put_task_struct(struct task_struct *t)
+{
+	SBUG();
+}
+EXPORT_SYMBOL(__put_task_struct);
+#endif /* HAVE_PUT_TASK_STRUCT */
+
 struct new_utsname *__utsname(void)
 {
 #ifdef HAVE_INIT_UTSNAME
diff --git a/module/spl/spl-rwlock.c b/module/spl/spl-rwlock.c
index 07fc2aae4..8ff66bf9f 100644
--- a/module/spl/spl-rwlock.c
+++ b/module/spl/spl-rwlock.c
@@ -33,6 +33,11 @@
 #define DEBUG_SUBSYSTEM S_RWLOCK
 
 #ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
+
+/*
+ * From lib/rwsem-spinlock.c but modified such that the caller is
+ * responsible for acquiring and dropping the sem->wait_lock.
+ */
 struct rwsem_waiter {
         struct list_head list;
         struct task_struct *task;
@@ -40,322 +45,49 @@ struct rwsem_waiter {
 #define RWSEM_WAITING_FOR_READ  0x00000001
 #define RWSEM_WAITING_FOR_WRITE 0x00000002
 };
+
 /* wake a single writer */
 static struct rw_semaphore *
 __rwsem_wake_one_writer_locked(struct rw_semaphore *sem)
 {
-	struct rwsem_waiter *waiter;
-	struct task_struct *tsk;
+        struct rwsem_waiter *waiter;
+        struct task_struct *tsk;
 
-	sem->activity = -1;
+        sem->activity = -1;
 
-	waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
-	list_del(&waiter->list);
+        waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
+        list_del(&waiter->list);
 
-	tsk = waiter->task;
-	smp_mb();
-	waiter->task = NULL;
-	wake_up_process(tsk);
-	put_task_struct(tsk);
-	return sem;
+        tsk = waiter->task;
+        smp_mb();
+        waiter->task = NULL;
+        wake_up_process(tsk);
+        put_task_struct(tsk);
+        return sem;
 }
 
 /* release a read lock on the semaphore */
-static void
+void
 __up_read_locked(struct rw_semaphore *sem)
 {
-	if (--sem->activity == 0 && !list_empty(&sem->wait_list))
-		(void)__rwsem_wake_one_writer_locked(sem);
+        if (--sem->activity == 0 && !list_empty(&sem->wait_list))
+                (void)__rwsem_wake_one_writer_locked(sem);
 }
+EXPORT_SYMBOL(__up_read_locked);
 
 /* trylock for writing -- returns 1 if successful, 0 if contention */
-static int
-__down_write_trylock_locked(struct rw_semaphore *sem)
-{
-	int ret = 0;
-
-	if (sem->activity == 0 && list_empty(&sem->wait_list)) {
-		/* granted */
-		sem->activity = -1;
-		ret = 1;
-	}
-
-	return ret;
-}
-#endif
-
-void
-__rw_init(krwlock_t *rwlp, char *name, krw_type_t type, void *arg)
-{
-	int flags = KM_SLEEP;
-
-        ASSERT(rwlp);
-        ASSERT(name);
-	ASSERT(type == RW_DEFAULT);	/* XXX no irq handler use */
-	ASSERT(arg == NULL);		/* XXX no irq handler use */
-
-	rwlp->rw_magic = RW_MAGIC;
-	rwlp->rw_owner = NULL;
-	rwlp->rw_name = NULL;
-        rwlp->rw_name_size = strlen(name) + 1;
-
-        /* We may be called when there is a non-zero preempt_count or
-         * interrupts are disabled is which case we must not sleep.
-         */
-        if (current_thread_info()->preempt_count || irqs_disabled())
-                flags = KM_NOSLEEP;
-
-        rwlp->rw_name = kmem_alloc(rwlp->rw_name_size, flags);
-        if (rwlp->rw_name == NULL)
-                return;
-
-	init_rwsem(&rwlp->rw_sem);
-        strcpy(rwlp->rw_name, name);
-}
-EXPORT_SYMBOL(__rw_init);
-
-void
-__rw_destroy(krwlock_t *rwlp)
-{
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-	ASSERT(rwlp->rw_owner == NULL);
-	spin_lock(&rwlp->rw_sem.wait_lock);
-	ASSERT(list_empty(&rwlp->rw_sem.wait_list));
-	spin_unlock(&rwlp->rw_sem.wait_lock);
-
-        kmem_free(rwlp->rw_name, rwlp->rw_name_size);
-
-	memset(rwlp, RW_POISON, sizeof(krwlock_t));
-}
-EXPORT_SYMBOL(__rw_destroy);
-
-/* Return 0 if the lock could not be obtained without blocking. */
 int
-__rw_tryenter(krwlock_t *rwlp, krw_t rw)
-{
-	int rc = 0;
-	ENTRY;
-
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-
-	switch (rw) {
-		/* these functions return 1 if success, 0 if contention */
-		case RW_READER:
-			/* Here the Solaris code would return 0
-			 * if there were any write waiters.  Specifically
-			 * thinking about the case where readers may have
-			 * the lock and we would also allow this thread
-			 * to grab the read lock with a writer waiting in the
-			 * queue. This doesn't seem like a correctness
-			 * issue, so just call down_read_trylock()
-			 * for the test.  We may have to revisit this if
-			 * it becomes an issue */
-			rc = down_read_trylock(&rwlp->rw_sem);
-			break;
-		case RW_WRITER:
-			rc = down_write_trylock(&rwlp->rw_sem);
-			if (rc) {
-				/* there better not be anyone else
-				 * holding the write lock here */
-				ASSERT(rwlp->rw_owner == NULL);
-				rwlp->rw_owner = current;
-			}
-			break;
-		default:
-			SBUG();
-	}
-
-	RETURN(rc);
-}
-EXPORT_SYMBOL(__rw_tryenter);
-
-void
-__rw_enter(krwlock_t *rwlp, krw_t rw)
-{
-	ENTRY;
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-
-	switch (rw) {
-		case RW_READER:
-			/* Here the Solaris code would block
-			 * if there were any write waiters.  Specifically
-			 * thinking about the case where readers may have
-			 * the lock and we would also allow this thread
-			 * to grab the read lock with a writer waiting in the
-			 * queue. This doesn't seem like a correctness
-			 * issue, so just call down_read()
-			 * for the test.  We may have to revisit this if
-			 * it becomes an issue */
-			down_read(&rwlp->rw_sem);
-			break;
-		case RW_WRITER:
-			down_write(&rwlp->rw_sem);
-
-			/* there better not be anyone else
-			 * holding the write lock here */
-			ASSERT(rwlp->rw_owner == NULL);
-			rwlp->rw_owner = current;
-			break;
-		default:
-			SBUG();
-	}
-	EXIT;
-}
-EXPORT_SYMBOL(__rw_enter);
-
-void
-__rw_exit(krwlock_t *rwlp)
-{
-	ENTRY;
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-
-	/* rw_owner is held by current
-	 * thread iff it is a writer */
-	if (rwlp->rw_owner == current) {
-		rwlp->rw_owner = NULL;
-		up_write(&rwlp->rw_sem);
-	} else {
-		up_read(&rwlp->rw_sem);
-	}
-	EXIT;
-}
-EXPORT_SYMBOL(__rw_exit);
-
-void
-__rw_downgrade(krwlock_t *rwlp)
-{
-	ENTRY;
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-	ASSERT(rwlp->rw_owner == current);
-
-	rwlp->rw_owner = NULL;
-	downgrade_write(&rwlp->rw_sem);
-	EXIT;
-}
-EXPORT_SYMBOL(__rw_downgrade);
-
-/* Return 0 if unable to perform the upgrade.
- * Might be wise to fix the caller
- * to acquire the write lock first?
- */
-int
-__rw_tryupgrade(krwlock_t *rwlp)
-{
-	int rc = 0;
-	ENTRY;
-
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-
-	spin_lock(&rwlp->rw_sem.wait_lock);
-
-	/* Check if there is anyone waiting for the
-	 * lock.  If there is, then we know we should
-	 * not try to upgrade the lock */
-	if (!list_empty(&rwlp->rw_sem.wait_list)) {
-		spin_unlock(&rwlp->rw_sem.wait_lock);
-		RETURN(0);
-	}
-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-	/* Note that activity is protected by
-	 * the wait_lock.  Don't try to upgrade
-	 * if there are multiple readers currently
-	 * holding the lock */
-	if (rwlp->rw_sem.activity > 1) {
-#else
-	/* Don't try to upgrade
-	 * if there are multiple readers currently
-	 * holding the lock */
-	if ((rwlp->rw_sem.count & RWSEM_ACTIVE_MASK) > 1) {
-#endif
-		spin_unlock(&rwlp->rw_sem.wait_lock);
-		RETURN(0);
-	}
-
-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-	/* Here it should be safe to drop the
-	 * read lock and reacquire it for writing since
-	 * we know there are no waiters */
-	__up_read_locked(&rwlp->rw_sem);
-
-	/* returns 1 if success, 0 if contention */
-	rc = __down_write_trylock_locked(&rwlp->rw_sem);
-#else
-	/* Here it should be safe to drop the
-	 * read lock and reacquire it for writing since
-	 * we know there are no waiters */
-	up_read(&rwlp->rw_sem);
-
-	/* returns 1 if success, 0 if contention */
-	rc = down_write_trylock(&rwlp->rw_sem);
-#endif
-
-	/* Check if upgrade failed.  Should not ever happen
-	 * if we got to this point */
-	ASSERT(rc);
-	ASSERT(rwlp->rw_owner == NULL);
-	rwlp->rw_owner = current;
-	spin_unlock(&rwlp->rw_sem.wait_lock);
-
-	RETURN(1);
-}
-EXPORT_SYMBOL(__rw_tryupgrade);
-
-kthread_t *
-__rw_owner(krwlock_t *rwlp)
+__down_write_trylock_locked(struct rw_semaphore *sem)
 {
-	ENTRY;
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-	RETURN(rwlp->rw_owner);
-}
-EXPORT_SYMBOL(__rw_owner);
+        int ret = 0;
 
-int
-__rw_read_held(krwlock_t *rwlp)
-{
-	ENTRY;
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-	RETURN(__rw_lock_held(rwlp) && rwlp->rw_owner == NULL);
-}
-EXPORT_SYMBOL(__rw_read_held);
+        if (sem->activity == 0 && list_empty(&sem->wait_list)) {
+                sem->activity = -1;
+                ret = 1;
+        }
 
-int
-__rw_write_held(krwlock_t *rwlp)
-{
-	ENTRY;
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-	RETURN(rwlp->rw_owner == current);
+        return ret;
 }
-EXPORT_SYMBOL(__rw_write_held);
-
-int
-__rw_lock_held(krwlock_t *rwlp)
-{
-	int rc = 0;
-	ENTRY;
+EXPORT_SYMBOL(__down_write_trylock_locked);
 
-	ASSERT(rwlp);
-	ASSERT(rwlp->rw_magic == RW_MAGIC);
-
-	spin_lock_irq(&(rwlp->rw_sem.wait_lock));
-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-	if (rwlp->rw_sem.activity != 0) {
-#else
-	if (rwlp->rw_sem.count != 0) {
 #endif
-		rc = 1;
-	}
-
-	spin_unlock_irq(&(rwlp->rw_sem.wait_lock));
-
-	RETURN(rc);
-}
-EXPORT_SYMBOL(__rw_lock_held);
diff --git a/module/splat/splat-internal.h b/module/splat/splat-internal.h
index c1c84d8d1..fea78e043 100644
--- a/module/splat/splat-internal.h
+++ b/module/splat/splat-internal.h
@@ -41,6 +41,7 @@
 #include <linux/device.h>
 #include <linux/list.h>
 #include <linux/swap.h>
+#include <linux/delay.h>
 
 #include <asm/ioctls.h>
 #include <asm/uaccess.h>
@@ -195,6 +196,15 @@ typedef struct splat_info {
 #define splat_vprint(file, test, format, args...)			\
 	splat_print(file, "%*s: " format, SPLAT_NAME_SIZE, test, args)
 
+#define splat_locked_test(lock, test)					\
+({									\
+	int _rc_;							\
+	spin_lock(lock);						\
+	_rc_ = (test) ? 1 : 0;						\
+	spin_unlock(lock);						\
+	_rc_;								\
+})
+
 splat_subsystem_t *splat_condvar_init(void);
 splat_subsystem_t *splat_kmem_init(void);
 splat_subsystem_t *splat_mutex_init(void);
diff --git a/module/splat/splat-rwlock.c b/module/splat/splat-rwlock.c
index 7f19dfb32..cf3670370 100644
--- a/module/splat/splat-rwlock.c
+++ b/module/splat/splat-rwlock.c
@@ -4,9 +4,9 @@
  *  Copyright (c) 2008 Lawrence Livermore National Security, LLC.
  *  Produced at Lawrence Livermore National Laboratory
  *  Written by:
- *          Brian Behlendorf <[email protected]>,
- *          Herb Wartens <[email protected]>,
- *          Jim Garlick <[email protected]>
+ *	  Brian Behlendorf <[email protected]>,
+ *	  Herb Wartens <[email protected]>,
+ *	  Jim Garlick <[email protected]>
  *  UCRL-CODE-235197
  *
  *  This is free software; you can redistribute it and/or modify it
@@ -30,210 +30,168 @@
 #define SPLAT_RWLOCK_DESC		"Kernel RW Lock Tests"
 
 #define SPLAT_RWLOCK_TEST1_ID		0x0701
-#define SPLAT_RWLOCK_TEST1_NAME		"rwtest1"
-#define SPLAT_RWLOCK_TEST1_DESC		"Multiple Readers One Writer"
+#define SPLAT_RWLOCK_TEST1_NAME		"N-rd/1-wr"
+#define SPLAT_RWLOCK_TEST1_DESC		"Multiple readers one writer"
 
 #define SPLAT_RWLOCK_TEST2_ID		0x0702
-#define SPLAT_RWLOCK_TEST2_NAME		"rwtest2"
-#define SPLAT_RWLOCK_TEST2_DESC		"Multiple Writers"
+#define SPLAT_RWLOCK_TEST2_NAME		"0-rd/N-wr"
+#define SPLAT_RWLOCK_TEST2_DESC		"Multiple writers"
 
 #define SPLAT_RWLOCK_TEST3_ID		0x0703
-#define SPLAT_RWLOCK_TEST3_NAME		"rwtest3"
-#define SPLAT_RWLOCK_TEST3_DESC		"Owner Verification"
+#define SPLAT_RWLOCK_TEST3_NAME		"held"
+#define SPLAT_RWLOCK_TEST3_DESC		"RW_{LOCK|READ|WRITE}_HELD"
 
 #define SPLAT_RWLOCK_TEST4_ID		0x0704
-#define SPLAT_RWLOCK_TEST4_NAME		"rwtest4"
-#define SPLAT_RWLOCK_TEST4_DESC		"Trylock Test"
+#define SPLAT_RWLOCK_TEST4_NAME		"tryenter"
+#define SPLAT_RWLOCK_TEST4_DESC		"Tryenter"
 
 #define SPLAT_RWLOCK_TEST5_ID		0x0705
-#define SPLAT_RWLOCK_TEST5_NAME		"rwtest5"
-#define SPLAT_RWLOCK_TEST5_DESC		"Write Downgrade Test"
+#define SPLAT_RWLOCK_TEST5_NAME		"rw_downgrade"
+#define SPLAT_RWLOCK_TEST5_DESC		"Write downgrade"
 
 #define SPLAT_RWLOCK_TEST6_ID		0x0706
-#define SPLAT_RWLOCK_TEST6_NAME		"rwtest6"
-#define SPLAT_RWLOCK_TEST6_DESC		"Read Upgrade Test"
+#define SPLAT_RWLOCK_TEST6_NAME		"rw_tryupgrade"
+#define SPLAT_RWLOCK_TEST6_DESC		"Read upgrade"
 
 #define SPLAT_RWLOCK_TEST_MAGIC		0x115599DDUL
 #define SPLAT_RWLOCK_TEST_NAME		"rwlock_test"
+#define SPLAT_RWLOCK_TEST_TASKQ		"rwlock_taskq"
 #define SPLAT_RWLOCK_TEST_COUNT		8
 
 #define SPLAT_RWLOCK_RELEASE_INIT	0
-#define SPLAT_RWLOCK_RELEASE_WRITERS	1
-#define SPLAT_RWLOCK_RELEASE_READERS	2
+#define SPLAT_RWLOCK_RELEASE_WR		1
+#define SPLAT_RWLOCK_RELEASE_RD		2
 
 typedef struct rw_priv {
-        unsigned long rw_magic;
-        struct file *rw_file;
-	krwlock_t rwl;
-	spinlock_t rw_priv_lock;
+	unsigned long rw_magic;
+	struct file *rw_file;
+	krwlock_t rw_rwlock;
+	spinlock_t rw_lock;
 	wait_queue_head_t rw_waitq;
-	atomic_t rw_completed;
-	atomic_t rw_acquired;
-	atomic_t rw_waiters;
-	atomic_t rw_release;
+	int rw_completed;
+	int rw_holders;
+	int rw_waiters;
+	int rw_release;
+	int rw_rc;
+	krw_type_t rw_type;
 } rw_priv_t;
 
 typedef struct rw_thr {
-	int rwt_id;
 	const char *rwt_name;
 	rw_priv_t *rwt_rwp;
-	int rwt_rc;
+	int rwt_id;
 } rw_thr_t;
 
-static inline void
-splat_rwlock_sleep(signed long delay)
-{
-	set_current_state(TASK_UNINTERRUPTIBLE);
-	schedule_timeout(delay);
-}
-
-#define splat_rwlock_lock_and_test(lock,test)	\
-({						\
-	int ret = 0;				\
-						\
-	spin_lock(lock);			\
-	ret = (test) ? 1 : 0;			\
-	spin_unlock(lock);			\
-	ret;					\
-})
-
-void splat_init_rw_priv(rw_priv_t *rwv, struct file *file)
+void splat_init_rw_priv(rw_priv_t *rwp, struct file *file)
 {
-	rwv->rw_magic = SPLAT_RWLOCK_TEST_MAGIC;
-	rwv->rw_file = file;
-	spin_lock_init(&rwv->rw_priv_lock);
-	init_waitqueue_head(&rwv->rw_waitq);
-	atomic_set(&rwv->rw_completed, 0);
-	atomic_set(&rwv->rw_acquired, 0);
-	atomic_set(&rwv->rw_waiters, 0);
-	atomic_set(&rwv->rw_release, SPLAT_RWLOCK_RELEASE_INIT);
-
-	/* Initialize the read/write lock */
-	rw_init(&rwv->rwl, SPLAT_RWLOCK_TEST_NAME, RW_DEFAULT, NULL);
+	rwp->rw_magic = SPLAT_RWLOCK_TEST_MAGIC;
+	rwp->rw_file = file;
+	rw_init(&rwp->rw_rwlock, SPLAT_RWLOCK_TEST_NAME, RW_DEFAULT, NULL);
+	spin_lock_init(&rwp->rw_lock);
+	init_waitqueue_head(&rwp->rw_waitq);
+	rwp->rw_completed = 0;
+	rwp->rw_holders = 0;
+	rwp->rw_waiters = 0;
+	rwp->rw_release = SPLAT_RWLOCK_RELEASE_INIT;
+	rwp->rw_rc = 0;
+	rwp->rw_type = 0;
 }
 
-int
-splat_rwlock_test1_writer_thread(void *arg)
+static int
+splat_rwlock_wr_thr(void *arg)
 {
 	rw_thr_t *rwt = (rw_thr_t *)arg;
-	rw_priv_t *rwv = rwt->rwt_rwp;
-	uint8_t rnd = 0;
+	rw_priv_t *rwp = rwt->rwt_rwp;
+	uint8_t rnd;
 	char name[16];
 
-	ASSERT(rwv->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
-        snprintf(name, sizeof(name), "%s%d",
-		 SPLAT_RWLOCK_TEST_NAME, rwt->rwt_id);
+	ASSERT(rwp->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
+	snprintf(name, sizeof(name), "rwlock_wr_thr%d", rwt->rwt_id);
 	daemonize(name);
 	get_random_bytes((void *)&rnd, 1);
-	splat_rwlock_sleep(rnd * HZ / 1000);
-
-	spin_lock(&rwv->rw_priv_lock);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s writer thread trying to acquire rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	atomic_inc(&rwv->rw_waiters);
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Take the semaphore for writing
-	 * release it when we are told to */
-	rw_enter(&rwv->rwl, RW_WRITER);
-
-	spin_lock(&rwv->rw_priv_lock);
-	atomic_dec(&rwv->rw_waiters);
-	atomic_inc(&rwv->rw_acquired);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s writer thread acquired rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Wait here until the control thread
-	 * says we can release the write lock */
-	wait_event_interruptible(rwv->rw_waitq,
-				 splat_rwlock_lock_and_test(&rwv->rw_priv_lock,
-					 atomic_read(&rwv->rw_release) ==
-					 SPLAT_RWLOCK_RELEASE_WRITERS));
-	spin_lock(&rwv->rw_priv_lock);
-	atomic_inc(&rwv->rw_completed);
-	atomic_dec(&rwv->rw_acquired);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s writer thread dropped rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Release the semaphore */
-	rw_exit(&rwv->rwl);
+	msleep((unsigned int)rnd);
+
+	splat_vprint(rwp->rw_file, rwt->rwt_name,
+		     "%s trying to acquire rwlock (%d holding/%d waiting)\n",
+		     name, rwp->rw_holders, rwp->rw_waiters);
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_waiters++;
+	spin_unlock(&rwp->rw_lock);
+	rw_enter(&rwp->rw_rwlock, RW_WRITER);
+
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_waiters--;
+	rwp->rw_holders++;
+	spin_unlock(&rwp->rw_lock);
+	splat_vprint(rwp->rw_file, rwt->rwt_name,
+		     "%s acquired rwlock (%d holding/%d waiting)\n",
+		     name, rwp->rw_holders, rwp->rw_waiters);
+
+	/* Wait for control thread to signal we can release the write lock */
+	wait_event_interruptible(rwp->rw_waitq, splat_locked_test(&rwp->rw_lock,
+				 rwp->rw_release == SPLAT_RWLOCK_RELEASE_WR));
+
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_completed++;
+	rwp->rw_holders--;
+	spin_unlock(&rwp->rw_lock);
+	splat_vprint(rwp->rw_file, rwt->rwt_name,
+		   "%s dropped rwlock (%d holding/%d waiting)\n",
+		   name, rwp->rw_holders, rwp->rw_waiters);
+
+	rw_exit(&rwp->rw_rwlock);
+
 	return 0;
 }
 
-int
-splat_rwlock_test1_reader_thread(void *arg)
+static int
+splat_rwlock_rd_thr(void *arg)
 {
 	rw_thr_t *rwt = (rw_thr_t *)arg;
-	rw_priv_t *rwv = rwt->rwt_rwp;
-	uint8_t rnd = 0;
+	rw_priv_t *rwp = rwt->rwt_rwp;
+	uint8_t rnd;
 	char name[16];
 
-	ASSERT(rwv->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
-        snprintf(name, sizeof(name), "%s%d",
-		 SPLAT_RWLOCK_TEST_NAME, rwt->rwt_id);
+	ASSERT(rwp->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
+	snprintf(name, sizeof(name), "rwlock_rd_thr%d", rwt->rwt_id);
 	daemonize(name);
 	get_random_bytes((void *)&rnd, 1);
-        splat_rwlock_sleep(rnd * HZ / 1000);
-
-	/* Don't try and and take the semaphore until
-	 * someone else has already acquired it */
-        wait_event_interruptible(rwv->rw_waitq,
-				 splat_rwlock_lock_and_test(&rwv->rw_priv_lock,
-					 atomic_read(&rwv->rw_acquired) > 0));
-
-	spin_lock(&rwv->rw_priv_lock);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s reader thread trying to acquire rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	atomic_inc(&rwv->rw_waiters);
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Take the semaphore for reading
-	 * release it when we are told to */
-	rw_enter(&rwv->rwl, RW_READER);
-
-	spin_lock(&rwv->rw_priv_lock);
-	atomic_dec(&rwv->rw_waiters);
-	atomic_inc(&rwv->rw_acquired);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s reader thread acquired rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Wait here until the control thread
-         * says we can release the read lock */
-	wait_event_interruptible(rwv->rw_waitq,
-				 splat_rwlock_lock_and_test(&rwv->rw_priv_lock,
-				 atomic_read(&rwv->rw_release) ==
-				 SPLAT_RWLOCK_RELEASE_READERS));
-
-	spin_lock(&rwv->rw_priv_lock);
-	atomic_inc(&rwv->rw_completed);
-	atomic_dec(&rwv->rw_acquired);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s reader thread dropped rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Release the semaphore */
-	rw_exit(&rwv->rwl);
+	msleep((unsigned int)rnd);
+
+	/* Don't try and take the semaphore until after someone has it */
+	wait_event_interruptible(rwp->rw_waitq, splat_locked_test(&rwp->rw_lock,
+				 rwp->rw_holders > 0));
+
+	splat_vprint(rwp->rw_file, rwt->rwt_name,
+		     "%s trying to acquire rwlock (%d holding/%d waiting)\n",
+		     name, rwp->rw_holders, rwp->rw_waiters);
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_waiters++;
+	spin_unlock(&rwp->rw_lock);
+	rw_enter(&rwp->rw_rwlock, RW_READER);
+
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_waiters--;
+	rwp->rw_holders++;
+	spin_unlock(&rwp->rw_lock);
+	splat_vprint(rwp->rw_file, rwt->rwt_name,
+		     "%s acquired rwlock (%d holding/%d waiting)\n",
+		     name, rwp->rw_holders, rwp->rw_waiters);
+
+	/* Wait for control thread to signal we can release the read lock */
+	wait_event_interruptible(rwp->rw_waitq, splat_locked_test(&rwp->rw_lock,
+				 rwp->rw_release == SPLAT_RWLOCK_RELEASE_RD));
+
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_completed++;
+	rwp->rw_holders--;
+	spin_unlock(&rwp->rw_lock);
+	splat_vprint(rwp->rw_file, rwt->rwt_name,
+		     "%s dropped rwlock (%d holding/%d waiting)\n",
+		     name, rwp->rw_holders, rwp->rw_waiters);
+
+	rw_exit(&rwp->rw_rwlock);
+
 	return 0;
 }
 
@@ -243,543 +201,467 @@ splat_rwlock_test1(struct file *file, void *arg)
 	int i, count = 0, rc = 0;
 	long pids[SPLAT_RWLOCK_TEST_COUNT];
 	rw_thr_t rwt[SPLAT_RWLOCK_TEST_COUNT];
-	rw_priv_t rwv;
+	rw_priv_t *rwp;
 
-	/* Initialize private data including the rwlock */
-	splat_init_rw_priv(&rwv, file);
+	rwp = (rw_priv_t *)kmalloc(sizeof(*rwp), GFP_KERNEL);
+	if (rwp == NULL)
+		return -ENOMEM;
+
+	splat_init_rw_priv(rwp, file);
 
 	/* Create some threads, the exact number isn't important just as
 	 * long as we know how many we managed to create and should expect. */
+
+
+
 	for (i = 0; i < SPLAT_RWLOCK_TEST_COUNT; i++) {
-		rwt[i].rwt_rwp = &rwv;
+		rwt[i].rwt_rwp = rwp;
 		rwt[i].rwt_id = i;
 		rwt[i].rwt_name = SPLAT_RWLOCK_TEST1_NAME;
-		rwt[i].rwt_rc = 0;
-
-		/* The first thread will be a writer */
-		if (i == 0) {
-			pids[i] = kernel_thread(splat_rwlock_test1_writer_thread,
-						&rwt[i], 0);
-		} else {
-			pids[i] = kernel_thread(splat_rwlock_test1_reader_thread,
-						&rwt[i], 0);
-		}
 
-		if (pids[i] >= 0) {
+		/* The first thread will be the writer */
+		if (i == 0)
+			pids[i] = kernel_thread(splat_rwlock_wr_thr, &rwt[i], 0);
+		else
+			pids[i] = kernel_thread(splat_rwlock_rd_thr, &rwt[i], 0);
+
+		if (pids[i] >= 0)
 			count++;
-		}
 	}
 
-	/* Once the writer has the lock, release the readers */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock, atomic_read(&rwv.rw_acquired) <= 0)) {
-		splat_rwlock_sleep(1 * HZ);
+	/* Wait for the writer */
+	while (splat_locked_test(&rwp->rw_lock, rwp->rw_holders == 0)) {
+		wake_up_interruptible(&rwp->rw_waitq);
+		msleep(100);
 	}
-	wake_up_interruptible(&rwv.rw_waitq);
 
-	/* Ensure that there is only 1 writer and all readers are waiting */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-				        atomic_read(&rwv.rw_acquired) != 1 ||
-					atomic_read(&rwv.rw_waiters) !=
-					SPLAT_RWLOCK_TEST_COUNT - 1)) {
+	/* Wait for 'count-1' readers */
+	while (splat_locked_test(&rwp->rw_lock, rwp->rw_waiters < count - 1)) {
+		wake_up_interruptible(&rwp->rw_waitq);
+		msleep(100);
+	}
 
-		splat_rwlock_sleep(1 * HZ);
+	/* Verify there is only one lock holder */
+	if (splat_locked_test(&rwp->rw_lock, rwp->rw_holders) != 1) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST1_NAME, "Only 1 holder "
+			     "expected for rwlock (%d holding/%d waiting)\n",
+			     rwp->rw_holders, rwp->rw_waiters);
+		rc = -EINVAL;
 	}
-	/* Relase the writer */
-	spin_lock(&rwv.rw_priv_lock);
-	atomic_set(&rwv.rw_release, SPLAT_RWLOCK_RELEASE_WRITERS);
-	spin_unlock(&rwv.rw_priv_lock);
-	wake_up_interruptible(&rwv.rw_waitq);
-
-	/* Now ensure that there are multiple reader threads holding the lock */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_acquired) <= 1)) {
-		splat_rwlock_sleep(1 * HZ);
+
+	/* Verify 'count-1' readers */
+	if (splat_locked_test(&rwp->rw_lock, rwp->rw_waiters != count - 1)) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST1_NAME, "Only %d waiters "
+			     "expected for rwlock (%d holding/%d waiting)\n",
+			     count - 1, rwp->rw_holders, rwp->rw_waiters);
+		rc = -EINVAL;
 	}
-	/* Release the readers */
-	spin_lock(&rwv.rw_priv_lock);
-	atomic_set(&rwv.rw_release, SPLAT_RWLOCK_RELEASE_READERS);
-	spin_unlock(&rwv.rw_priv_lock);
-	wake_up_interruptible(&rwv.rw_waitq);
 
-	/* Wait for the test to complete */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_acquired) != 0 ||
-	       atomic_read(&rwv.rw_waiters) != 0)) {
-		splat_rwlock_sleep(1 * HZ);
+	/* Signal the writer to release, allows readers to acquire */
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_release = SPLAT_RWLOCK_RELEASE_WR;
+	wake_up_interruptible(&rwp->rw_waitq);
+	spin_unlock(&rwp->rw_lock);
 
+	/* Wait for 'count-1' readers to hold the lock */
+	while (splat_locked_test(&rwp->rw_lock, rwp->rw_holders < count - 1)) {
+		wake_up_interruptible(&rwp->rw_waitq);
+		msleep(100);
 	}
 
-	rw_destroy(&rwv.rwl);
-	return rc;
-}
+	/* Verify there are 'count-1' readers */
+	if (splat_locked_test(&rwp->rw_lock, rwp->rw_holders != count - 1)) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST1_NAME, "Only %d holders "
+			     "expected for rwlock (%d holding/%d waiting)\n",
+			     count - 1, rwp->rw_holders, rwp->rw_waiters);
+		rc = -EINVAL;
+	}
 
-int
-splat_rwlock_test2_writer_thread(void *arg)
-{
-	rw_thr_t *rwt = (rw_thr_t *)arg;
-	rw_priv_t *rwv = rwt->rwt_rwp;
-	uint8_t rnd = 0;
-	char name[16];
+	/* Release 'count-1' readers */
+	spin_lock(&rwp->rw_lock);
+	rwp->rw_release = SPLAT_RWLOCK_RELEASE_RD;
+	wake_up_interruptible(&rwp->rw_waitq);
+	spin_unlock(&rwp->rw_lock);
 
-	ASSERT(rwv->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
-	snprintf(name, sizeof(name), "%s%d",
-		 SPLAT_RWLOCK_TEST_NAME, rwt->rwt_id);
-	daemonize(name);
-	get_random_bytes((void *)&rnd, 1);
-	splat_rwlock_sleep(rnd * HZ / 1000);
-
-	/* Here just increment the waiters count even if we are not
-	 * exactly about to call rw_enter().  Not really a big deal
-	 * since more than likely will be true when we simulate work
-	 * later on */
-	spin_lock(&rwv->rw_priv_lock);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s writer thread trying to acquire rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	atomic_inc(&rwv->rw_waiters);
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Wait here until the control thread
-	 * says we can acquire the write lock */
-	wait_event_interruptible(rwv->rw_waitq,
-				 splat_rwlock_lock_and_test(&rwv->rw_priv_lock,
-				 atomic_read(&rwv->rw_release) ==
-				 SPLAT_RWLOCK_RELEASE_WRITERS));
-
-	/* Take the semaphore for writing */
-	rw_enter(&rwv->rwl, RW_WRITER);
-
-	spin_lock(&rwv->rw_priv_lock);
-	atomic_dec(&rwv->rw_waiters);
-	atomic_inc(&rwv->rw_acquired);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s writer thread acquired rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Give up the processor for a bit to simulate
-	 * doing some work while taking the write lock */
-	splat_rwlock_sleep(rnd * HZ / 1000);
-
-	/* Ensure that we are the only one writing */
-	if (atomic_read(&rwv->rw_acquired) > 1) {
-		rwt->rwt_rc = 1;
-	} else {
-		rwt->rwt_rc = 0;
-	}
+	/* Wait for the test to complete */
+	while (splat_locked_test(&rwp->rw_lock,
+				 rwp->rw_holders>0 || rwp->rw_waiters>0))
+		msleep(100);
 
-	spin_lock(&rwv->rw_priv_lock);
-	atomic_inc(&rwv->rw_completed);
-	atomic_dec(&rwv->rw_acquired);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s writer thread dropped rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
+	rw_destroy(&(rwp->rw_rwlock));
+	kfree(rwp);
 
-	rw_exit(&rwv->rwl);
+	return rc;
+}
 
-	return 0;
+static void
+splat_rwlock_test2_func(void *arg)
+{
+	rw_priv_t *rwp = (rw_priv_t *)arg;
+	int rc;
+	ASSERT(rwp->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
+
+	/* Read the value before sleeping and write it after we wake up to
+	 * maximize the chance of a race if rwlocks are not working properly */
+	rw_enter(&rwp->rw_rwlock, RW_WRITER);
+	rc = rwp->rw_rc;
+	set_current_state(TASK_INTERRUPTIBLE);
+	schedule_timeout(HZ / 100);  /* 1/100 of a second */
+	VERIFY(rwp->rw_rc == rc);
+	rwp->rw_rc = rc + 1;
+	rw_exit(&rwp->rw_rwlock);
 }
 
 static int
 splat_rwlock_test2(struct file *file, void *arg)
 {
-	int i, count = 0, rc = 0;
-	long pids[SPLAT_RWLOCK_TEST_COUNT];
-	rw_thr_t rwt[SPLAT_RWLOCK_TEST_COUNT];
-	rw_priv_t rwv;
+	rw_priv_t *rwp;
+	taskq_t *tq;
+	int i, rc = 0, tq_count = 256;
 
-	/* Initialize private data including the rwlock */
-	splat_init_rw_priv(&rwv, file);
+	rwp = (rw_priv_t *)kmalloc(sizeof(*rwp), GFP_KERNEL);
+	if (rwp == NULL)
+		return -ENOMEM;
 
-	/* Create some threads, the exact number isn't important just as
-	 * long as we know how many we managed to create and should expect. */
-	for (i = 0; i < SPLAT_RWLOCK_TEST_COUNT; i++) {
-		rwt[i].rwt_rwp = &rwv;
-		rwt[i].rwt_id = i;
-		rwt[i].rwt_name = SPLAT_RWLOCK_TEST2_NAME;
-		rwt[i].rwt_rc = 0;
+	splat_init_rw_priv(rwp, file);
 
-		/* The first thread will be a writer */
-		pids[i] = kernel_thread(splat_rwlock_test2_writer_thread,
-					&rwt[i], 0);
-
-		if (pids[i] >= 0) {
-			count++;
-		}
+	/* Create several threads allowing tasks to race with each other */
+	tq = taskq_create(SPLAT_RWLOCK_TEST_TASKQ, num_online_cpus(),
+			  maxclsyspri, 50, INT_MAX, TASKQ_PREPOPULATE);
+	if (tq == NULL) {
+		rc = -ENOMEM;
+		goto out;
 	}
 
-	/* Wait for writers to get queued up */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_waiters) < SPLAT_RWLOCK_TEST_COUNT)) {
-		splat_rwlock_sleep(1 * HZ);
+	/*
+	 * Schedule N work items to the work queue each of which enters the
+	 * writer rwlock, sleeps briefly, then exits the writer rwlock.  On a
+	 * multiprocessor box these work items will be handled by all available
+	 * CPUs.  The task function checks to ensure the tracked shared variable
+	 * is always only incremented by one.  Additionally, the rwlock itself
+	 * is instrumented such that if any two processors are in the
+	 * critical region at the same time the system will panic.  If the
+	 * rwlock is implemented right this will never happy, that's a pass.
+	 */
+	for (i = 0; i < tq_count; i++) {
+		if (!taskq_dispatch(tq,splat_rwlock_test2_func,rwp,TQ_SLEEP)) {
+			splat_vprint(file, SPLAT_RWLOCK_TEST2_NAME,
+				     "Failed to queue task %d\n", i);
+			rc = -EINVAL;
+		}
 	}
-	/* Relase the writers */
-	spin_lock(&rwv.rw_priv_lock);
-	atomic_set(&rwv.rw_release, SPLAT_RWLOCK_RELEASE_WRITERS);
-	spin_unlock(&rwv.rw_priv_lock);
-	wake_up_interruptible(&rwv.rw_waitq);
 
-	/* Wait for the test to complete */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_acquired) != 0 ||
-	       atomic_read(&rwv.rw_waiters) != 0)) {
-		splat_rwlock_sleep(HZ);
-	}
+	taskq_wait(tq);
 
-	/* If any of the write threads ever acquired the lock
-	 * while another thread had it, make sure we return
-	 * an error */
-	for (i = 0; i < SPLAT_RWLOCK_TEST_COUNT; i++) {
-		if (rwt[i].rwt_rc) {
-			rc++;
-		}
+	if (rwp->rw_rc == tq_count) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST2_NAME, "%d racing threads "
+			     "correctly entered/exited the rwlock %d times\n",
+			     num_online_cpus(), rwp->rw_rc);
+	} else {
+		splat_vprint(file, SPLAT_RWLOCK_TEST2_NAME, "%d racing threads "
+			     "only processed %d/%d w rwlock work items\n",
+			     num_online_cpus(), rwp->rw_rc, tq_count);
+		rc = -EINVAL;
 	}
 
-	rw_destroy(&rwv.rwl);
+	taskq_destroy(tq);
+	rw_destroy(&(rwp->rw_rwlock));
+out:
+	kfree(rwp);
 	return rc;
 }
 
+#define splat_rwlock_test3_helper(rwp,rex1,rex2,wex1,wex2,held_func,rc)	\
+do {									\
+	int result, _rc1_, _rc2_, _rc3_, _rc4_;				\
+									\
+	rc = 0;								\
+	rw_enter(&(rwp)->rw_rwlock, RW_READER);				\
+	_rc1_ = ((result = held_func(&(rwp)->rw_rwlock)) != rex1);	\
+	splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "%s" #held_func	\
+		     " returned %d (expected %d) when RW_READER\n",	\
+		     _rc1_ ? "Fail " : "", result, rex1);		\
+	rw_exit(&(rwp)->rw_rwlock);					\
+	_rc2_ = ((result = held_func(&(rwp)->rw_rwlock)) != rex2);	\
+	splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "%s" #held_func	\
+		     " returned %d (expected %d) when !RW_READER\n",	\
+		     _rc2_ ? "Fail " : "", result, rex2);		\
+									\
+	rw_enter(&(rwp)->rw_rwlock, RW_WRITER);				\
+	_rc3_ = ((result = held_func(&(rwp)->rw_rwlock)) != wex1);	\
+	splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "%s" #held_func	\
+		     " returned %d (expected %d) when RW_WRITER\n",	\
+		     _rc3_ ? "Fail " : "", result, wex1);		\
+	rw_exit(&(rwp)->rw_rwlock);					\
+	_rc4_ = ((result = held_func(&(rwp)->rw_rwlock)) != wex2);	\
+	splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "%s" #held_func	\
+		     " returned %d (expected %d) when !RW_WRITER\n",	\
+		     _rc4_ ? "Fail " : "", result, wex2);		\
+									\
+	rc = ((_rc1_ ||  _rc2_ || _rc3_ || _rc4_) ? -EINVAL : 0);	\
+} while(0);
+
 static int
 splat_rwlock_test3(struct file *file, void *arg)
 {
-	kthread_t *owner;
-	rw_priv_t rwv;
-	int rc = 0;
-
-	/* Initialize private data 
-	 * including the rwlock */
-	splat_init_rw_priv(&rwv, file);
-
-	/* Take the rwlock for writing */
-	rw_enter(&rwv.rwl, RW_WRITER);
-	owner = rw_owner(&rwv.rwl);
-	if (current != owner) {
-		splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "rwlock should "
-			   "be owned by pid %d but is owned by pid %d\n",
-			   current->pid, owner ? owner->pid : -1);
-		rc = -EINVAL;
-		goto out;
-	}
+	rw_priv_t *rwp;
+	int rc1, rc2, rc3;
 
-	/* Release the rwlock */
-	rw_exit(&rwv.rwl);
-	owner = rw_owner(&rwv.rwl);
-	if (owner) {
-		splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "rwlock should not "
-			   "be owned but is owned by pid %d\n", owner->pid);
-		rc = -EINVAL;
-		goto out;
-	}
+	rwp = (rw_priv_t *)kmalloc(sizeof(*rwp), GFP_KERNEL);
+	if (rwp == NULL)
+		return -ENOMEM;
 
-	/* Take the rwlock for reading.
-	 * Should not have an owner */
-	rw_enter(&rwv.rwl, RW_READER);
-	owner = rw_owner(&rwv.rwl);
-	if (owner) {
-		splat_vprint(file, SPLAT_RWLOCK_TEST3_NAME, "rwlock should not "
-			   "be owned but is owned by pid %d\n", owner->pid);
-		/* Release the rwlock */
-		rw_exit(&rwv.rwl);
-		rc = -EINVAL;
-		goto out;
-	}
+	splat_init_rw_priv(rwp, file);
 
-	/* Release the rwlock */
-	rw_exit(&rwv.rwl);
+	splat_rwlock_test3_helper(rwp, 1, 0, 1, 0, RW_LOCK_HELD, rc1);
+	splat_rwlock_test3_helper(rwp, 1, 0, 0, 0, RW_READ_HELD, rc2);
+	splat_rwlock_test3_helper(rwp, 0, 0, 1, 0, RW_WRITE_HELD, rc3);
 
-out:
-	rw_destroy(&rwv.rwl);
-	return rc;
+	rw_destroy(&rwp->rw_rwlock);
+	kfree(rwp);
+
+	return ((rc1 || rc2 || rc3) ? -EINVAL : 0);
 }
 
-int
-splat_rwlock_test4_reader_thread(void *arg)
+static void
+splat_rwlock_test4_func(void *arg)
 {
-	rw_thr_t *rwt = (rw_thr_t *)arg;
-	rw_priv_t *rwv = rwt->rwt_rwp;
-	uint8_t rnd = 0;
-	char name[16];
+	rw_priv_t *rwp = (rw_priv_t *)arg;
+	ASSERT(rwp->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
 
-	ASSERT(rwv->rw_magic == SPLAT_RWLOCK_TEST_MAGIC);
-        snprintf(name, sizeof(name), "%s%d",
-		 SPLAT_RWLOCK_TEST_NAME, rwt->rwt_id);
-	daemonize(name);
-	get_random_bytes((void *)&rnd, 1);
-        splat_rwlock_sleep(rnd * HZ / 1000);
-
-	/* Don't try and and take the semaphore until
-	 * someone else has already acquired it */
-        wait_event_interruptible(rwv->rw_waitq,
-				 splat_rwlock_lock_and_test(&rwv->rw_priv_lock,
-				 atomic_read(&rwv->rw_acquired) > 0));
-
-	spin_lock(&rwv->rw_priv_lock);
-	splat_vprint(rwv->rw_file, rwt->rwt_name,
-	           "%s reader thread trying to acquire rwlock with "
-		   "%d holding lock and %d waiting\n",
-		   name, atomic_read(&rwv->rw_acquired),
-		   atomic_read(&rwv->rw_waiters));
-	spin_unlock(&rwv->rw_priv_lock);
-
-	/* Take the semaphore for reading
-	 * release it when we are told to */
-	rwt->rwt_rc = rw_tryenter(&rwv->rwl, RW_READER);
-
-	/* Here we acquired the lock this is a
-	 * failure since the writer should be
-	 * holding the lock */
-	if (rwt->rwt_rc == 1) {
-		spin_lock(&rwv->rw_priv_lock);
-		atomic_inc(&rwv->rw_acquired);
-		splat_vprint(rwv->rw_file, rwt->rwt_name,
-			   "%s reader thread acquired rwlock with "
-			   "%d holding lock and %d waiting\n",
-			   name, atomic_read(&rwv->rw_acquired),
-			   atomic_read(&rwv->rw_waiters));
-		spin_unlock(&rwv->rw_priv_lock);
-
-		spin_lock(&rwv->rw_priv_lock);
-		atomic_dec(&rwv->rw_acquired);
-		splat_vprint(rwv->rw_file, rwt->rwt_name,
-			   "%s reader thread dropped rwlock with "
-			   "%d holding lock and %d waiting\n",
-			   name, atomic_read(&rwv->rw_acquired),
-			   atomic_read(&rwv->rw_waiters));
-		spin_unlock(&rwv->rw_priv_lock);
-
-		/* Release the semaphore */
-		rw_exit(&rwv->rwl);
+	if (rw_tryenter(&rwp->rw_rwlock, rwp->rw_type)) {
+		rwp->rw_rc = 0;
+		rw_exit(&rwp->rw_rwlock);
+	} else {
+		rwp->rw_rc = -EBUSY;
 	}
-	/* Here we know we didn't block and didn't
-	 * acquire the rwlock for reading */
-	else {
-		spin_lock(&rwv->rw_priv_lock);
-		atomic_inc(&rwv->rw_completed);
-		splat_vprint(rwv->rw_file, rwt->rwt_name,
-			   "%s reader thread could not acquire rwlock with "
-			   "%d holding lock and %d waiting\n",
-			   name, atomic_read(&rwv->rw_acquired),
-			   atomic_read(&rwv->rw_waiters));
-		spin_unlock(&rwv->rw_priv_lock);
+}
+
+static char *
+splat_rwlock_test4_name(krw_t type)
+{
+	switch (type) {
+		case RW_NONE: return "RW_NONE";
+		case RW_WRITER: return "RW_WRITER";
+		case RW_READER: return "RW_READER";
 	}
 
-	return 0;
+	return NULL;
 }
 
 static int
-splat_rwlock_test4(struct file *file, void *arg)
+splat_rwlock_test4_type(taskq_t *tq, rw_priv_t *rwp, int expected_rc,
+			krw_t holder_type, krw_t try_type)
 {
-	int i, count = 0, rc = 0;
-	long pids[SPLAT_RWLOCK_TEST_COUNT];
-	rw_thr_t rwt[SPLAT_RWLOCK_TEST_COUNT];
-	rw_priv_t rwv;
+	int id, rc = 0;
 
-	/* Initialize private data 
-	 * including the rwlock */
-	splat_init_rw_priv(&rwv, file);
-
-	/* Create some threads, the exact number isn't important just as
-	 * long as we know how many we managed to create and should expect. */
-	for (i = 0; i < SPLAT_RWLOCK_TEST_COUNT; i++) {
-		rwt[i].rwt_rwp = &rwv;
-		rwt[i].rwt_id = i;
-		rwt[i].rwt_name = SPLAT_RWLOCK_TEST4_NAME;
-		rwt[i].rwt_rc = 0;
-
-		/* The first thread will be a writer */
-		if (i == 0) {
-			/* We can reuse the test1 writer thread here */
-			pids[i] = kernel_thread(splat_rwlock_test1_writer_thread,
-						&rwt[i], 0);
-		} else {
-			 pids[i] = kernel_thread(splat_rwlock_test4_reader_thread,
-						&rwt[i], 0);
-		}
+	/* Schedule a task function which will try and acquire the rwlock
+	 * using type try_type while the rwlock is being held as holder_type.
+	 * The result must match expected_rc for the test to pass */
+	rwp->rw_rc = -EINVAL;
+	rwp->rw_type = try_type;
 
-		if (pids[i] >= 0) {
-			count++;
-		}
-	}
+	if (holder_type == RW_WRITER || holder_type == RW_READER)
+		rw_enter(&rwp->rw_rwlock, holder_type);
 
-	/* Once the writer has the lock, release the readers */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_acquired) <= 0)) {
-		splat_rwlock_sleep(1 * HZ);
+	id = taskq_dispatch(tq, splat_rwlock_test4_func, rwp, TQ_SLEEP);
+	if (id == 0) {
+		splat_vprint(rwp->rw_file, SPLAT_RWLOCK_TEST4_NAME, "%s",
+			     "taskq_dispatch() failed\n");
+		rc = -EINVAL;
+		goto out;
 	}
-	wake_up_interruptible(&rwv.rw_waitq);
 
-	/* Make sure that the reader threads complete */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_completed) != SPLAT_RWLOCK_TEST_COUNT - 1)) {
-		splat_rwlock_sleep(1 * HZ);
-	}
-	/* Release the writer */
-	spin_lock(&rwv.rw_priv_lock);
-	atomic_set(&rwv.rw_release, SPLAT_RWLOCK_RELEASE_WRITERS);
-	spin_unlock(&rwv.rw_priv_lock);
-	wake_up_interruptible(&rwv.rw_waitq);
+	taskq_wait_id(tq, id);
 
-	/* Wait for the test to complete */
-	while (splat_rwlock_lock_and_test(&rwv.rw_priv_lock,
-	       atomic_read(&rwv.rw_acquired) != 0 ||
-	       atomic_read(&rwv.rw_waiters) != 0)) {
-		splat_rwlock_sleep(1 * HZ);
-	}
+	if (rwp->rw_rc != expected_rc)
+		rc = -EINVAL;
 
-	/* If any of the reader threads ever acquired the lock
-	 * while another thread had it, make sure we return
-	 * an error since the rw_tryenter() should have failed */
-	for (i = 0; i < SPLAT_RWLOCK_TEST_COUNT; i++) {
-		if (rwt[i].rwt_rc) {
-			rc++;
-		}
-	}
+	splat_vprint(rwp->rw_file, SPLAT_RWLOCK_TEST4_NAME,
+		     "%srw_tryenter(%s) returned %d (expected %d) when %s\n",
+		     rc ? "Fail " : "", splat_rwlock_test4_name(try_type),
+		     rwp->rw_rc, expected_rc,
+		     splat_rwlock_test4_name(holder_type));
+out:
+	if (holder_type == RW_WRITER || holder_type == RW_READER)
+		rw_exit(&rwp->rw_rwlock);
 
-	rw_destroy(&rwv.rwl);
 	return rc;
 }
 
 static int
-splat_rwlock_test5(struct file *file, void *arg)
+splat_rwlock_test4(struct file *file, void *arg)
 {
-	kthread_t *owner;
-	rw_priv_t rwv;
-	int rc = 0;
-
-	/* Initialize private data 
-	 * including the rwlock */
-	splat_init_rw_priv(&rwv, file);
-
-	/* Take the rwlock for writing */
-	rw_enter(&rwv.rwl, RW_WRITER);
-	owner = rw_owner(&rwv.rwl);
-	if (current != owner) {
-		splat_vprint(file, SPLAT_RWLOCK_TEST5_NAME, "rwlock should "
-			   "be owned by pid %d but is owned by pid %d\n",
-			   current->pid, owner ? owner->pid : -1);
-		rc = -EINVAL;
+	rw_priv_t *rwp;
+	taskq_t *tq;
+	int rc = 0, rc1, rc2, rc3, rc4, rc5, rc6;
+
+	rwp = (rw_priv_t *)kmalloc(sizeof(*rwp), GFP_KERNEL);
+	if (rwp == NULL)
+		return -ENOMEM;
+
+	tq = taskq_create(SPLAT_RWLOCK_TEST_TASKQ, 1, maxclsyspri,
+			  50, INT_MAX, TASKQ_PREPOPULATE);
+	if (tq == NULL) {
+		rc = -ENOMEM;
 		goto out;
 	}
 
-	/* Make sure that the downgrade
-	 * worked properly */
-	rw_downgrade(&rwv.rwl);
+	splat_init_rw_priv(rwp, file);
+
+	/* Validate all combinations of rw_tryenter() contention */
+	rc1 = splat_rwlock_test4_type(tq, rwp, -EBUSY, RW_WRITER, RW_WRITER);
+	rc2 = splat_rwlock_test4_type(tq, rwp, -EBUSY, RW_WRITER, RW_READER);
+	rc3 = splat_rwlock_test4_type(tq, rwp, -EBUSY, RW_READER, RW_WRITER);
+	rc4 = splat_rwlock_test4_type(tq, rwp, 0,      RW_READER, RW_READER);
+	rc5 = splat_rwlock_test4_type(tq, rwp, 0,      RW_NONE,   RW_WRITER);
+	rc6 = splat_rwlock_test4_type(tq, rwp, 0,      RW_NONE,   RW_READER);
 
-	owner = rw_owner(&rwv.rwl);
-	if (owner) {
-		splat_vprint(file, SPLAT_RWLOCK_TEST5_NAME, "rwlock should not "
-			   "be owned but is owned by pid %d\n", owner->pid);
-		/* Release the rwlock */
-		rw_exit(&rwv.rwl);
+	if (rc1 || rc2 || rc3 || rc4 || rc5 || rc6)
 		rc = -EINVAL;
+
+	taskq_destroy(tq);
+out:
+	rw_destroy(&(rwp->rw_rwlock));
+	kfree(rwp);
+
+	return rc;
+}
+
+static int
+splat_rwlock_test5(struct file *file, void *arg)
+{
+	rw_priv_t *rwp;
+	int rc = -EINVAL;
+
+	rwp = (rw_priv_t *)kmalloc(sizeof(*rwp), GFP_KERNEL);
+	if (rwp == NULL)
+		return -ENOMEM;
+
+	splat_init_rw_priv(rwp, file);
+
+	rw_enter(&rwp->rw_rwlock, RW_WRITER);
+	if (!RW_WRITE_HELD(&rwp->rw_rwlock)) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST5_NAME,
+			     "rwlock should be write lock: %d\n",
+			     RW_WRITE_HELD(&rwp->rw_rwlock));
 		goto out;
 	}
 
-	/* Release the rwlock */
-	rw_exit(&rwv.rwl);
+	rw_downgrade(&rwp->rw_rwlock);
+	if (!RW_READ_HELD(&rwp->rw_rwlock)) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST5_NAME,
+			     "rwlock should be read lock: %d\n",
+			     RW_READ_HELD(&rwp->rw_rwlock));
+		goto out;
+	}
 
+	rc = 0;
+	splat_vprint(file, SPLAT_RWLOCK_TEST5_NAME, "%s",
+		     "rwlock properly downgraded\n");
 out:
-	rw_destroy(&rwv.rwl);
+	rw_exit(&rwp->rw_rwlock);
+	rw_destroy(&rwp->rw_rwlock);
+	kfree(rwp);
+
 	return rc;
 }
 
 static int
 splat_rwlock_test6(struct file *file, void *arg)
 {
-	kthread_t *owner;
-	rw_priv_t rwv;
-	int rc = 0;
-
-	/* Initialize private data 
-	 * including the rwlock */
-	splat_init_rw_priv(&rwv, file);
-
-	/* Take the rwlock for reading */
-	rw_enter(&rwv.rwl, RW_READER);
-	owner = rw_owner(&rwv.rwl);
-	if (owner) {
-		splat_vprint(file, SPLAT_RWLOCK_TEST6_NAME, "rwlock should not "
-			   "be owned but is owned by pid %d\n", owner->pid);
-		rc = -EINVAL;
+	rw_priv_t *rwp;
+	int rc = -EINVAL;
+
+	rwp = (rw_priv_t *)kmalloc(sizeof(*rwp), GFP_KERNEL);
+	if (rwp == NULL)
+		return -ENOMEM;
+
+	splat_init_rw_priv(rwp, file);
+
+	rw_enter(&rwp->rw_rwlock, RW_READER);
+	if (!RW_READ_HELD(&rwp->rw_rwlock)) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST6_NAME,
+		             "rwlock should be read lock: %d\n",
+			     RW_READ_HELD(&rwp->rw_rwlock));
 		goto out;
 	}
 
-	/* Make sure that the upgrade
-	 * worked properly */
-	rc = !rw_tryupgrade(&rwv.rwl);
+	/* With one reader upgrade should never fail */
+	rc = rw_tryupgrade(&rwp->rw_rwlock);
+	if (!rc) {
+		splat_vprint(file, SPLAT_RWLOCK_TEST6_NAME,
+			     "rwlock contended preventing upgrade: %d\n",
+			     RW_COUNT(&rwp->rw_rwlock));
+		goto out;
+	}
 
-	owner = rw_owner(&rwv.rwl);
-	if (rc || current != owner) {
+	if (RW_READ_HELD(&rwp->rw_rwlock) || !RW_WRITE_HELD(&rwp->rw_rwlock)) {
 		splat_vprint(file, SPLAT_RWLOCK_TEST6_NAME, "rwlock should "
-			   "be owned by pid %d but is owned by pid %d "
-			   "trylock rc %d\n",
-			   current->pid, owner ? owner->pid : -1, rc);
-		rc = -EINVAL;
+			   "have 0 (not %d) reader and 1 (not %d) writer\n",
+			   RW_READ_HELD(&rwp->rw_rwlock),
+			   RW_WRITE_HELD(&rwp->rw_rwlock));
 		goto out;
 	}
 
-	/* Release the rwlock */
-	rw_exit(&rwv.rwl);
-
+	rc = 0;
+	splat_vprint(file, SPLAT_RWLOCK_TEST6_NAME, "%s",
+		     "rwlock properly upgraded\n");
 out:
-	rw_destroy(&rwv.rwl);
+	rw_exit(&rwp->rw_rwlock);
+	rw_destroy(&rwp->rw_rwlock);
+	kfree(rwp);
+
 	return rc;
 }
 
 splat_subsystem_t *
 splat_rwlock_init(void)
 {
-        splat_subsystem_t *sub;
-
-        sub = kmalloc(sizeof(*sub), GFP_KERNEL);
-        if (sub == NULL)
-                return NULL;
-
-        memset(sub, 0, sizeof(*sub));
-        strncpy(sub->desc.name, SPLAT_RWLOCK_NAME, SPLAT_NAME_SIZE);
-        strncpy(sub->desc.desc, SPLAT_RWLOCK_DESC, SPLAT_DESC_SIZE);
-        INIT_LIST_HEAD(&sub->subsystem_list);
-        INIT_LIST_HEAD(&sub->test_list);
-        spin_lock_init(&sub->test_lock);
-        sub->desc.id = SPLAT_SUBSYSTEM_RWLOCK;
-
-        SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST1_NAME, SPLAT_RWLOCK_TEST1_DESC,
-                      SPLAT_RWLOCK_TEST1_ID, splat_rwlock_test1);
-        SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST2_NAME, SPLAT_RWLOCK_TEST2_DESC,
-                      SPLAT_RWLOCK_TEST2_ID, splat_rwlock_test2);
-        SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST3_NAME, SPLAT_RWLOCK_TEST3_DESC,
-                      SPLAT_RWLOCK_TEST3_ID, splat_rwlock_test3);
-        SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST4_NAME, SPLAT_RWLOCK_TEST4_DESC,
-                      SPLAT_RWLOCK_TEST4_ID, splat_rwlock_test4);
-        SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST5_NAME, SPLAT_RWLOCK_TEST5_DESC,
-                      SPLAT_RWLOCK_TEST5_ID, splat_rwlock_test5);
-        SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST6_NAME, SPLAT_RWLOCK_TEST6_DESC,
-                      SPLAT_RWLOCK_TEST6_ID, splat_rwlock_test6);
-
-        return sub;
+	splat_subsystem_t *sub;
+
+	sub = kmalloc(sizeof(*sub), GFP_KERNEL);
+	if (sub == NULL)
+		return NULL;
+
+	memset(sub, 0, sizeof(*sub));
+	strncpy(sub->desc.name, SPLAT_RWLOCK_NAME, SPLAT_NAME_SIZE);
+	strncpy(sub->desc.desc, SPLAT_RWLOCK_DESC, SPLAT_DESC_SIZE);
+	INIT_LIST_HEAD(&sub->subsystem_list);
+	INIT_LIST_HEAD(&sub->test_list);
+	spin_lock_init(&sub->test_lock);
+	sub->desc.id = SPLAT_SUBSYSTEM_RWLOCK;
+
+	SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST1_NAME, SPLAT_RWLOCK_TEST1_DESC,
+		      SPLAT_RWLOCK_TEST1_ID, splat_rwlock_test1);
+	SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST2_NAME, SPLAT_RWLOCK_TEST2_DESC,
+		      SPLAT_RWLOCK_TEST2_ID, splat_rwlock_test2);
+	SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST3_NAME, SPLAT_RWLOCK_TEST3_DESC,
+		      SPLAT_RWLOCK_TEST3_ID, splat_rwlock_test3);
+	SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST4_NAME, SPLAT_RWLOCK_TEST4_DESC,
+		      SPLAT_RWLOCK_TEST4_ID, splat_rwlock_test4);
+	SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST5_NAME, SPLAT_RWLOCK_TEST5_DESC,
+		      SPLAT_RWLOCK_TEST5_ID, splat_rwlock_test5);
+	SPLAT_TEST_INIT(sub, SPLAT_RWLOCK_TEST6_NAME, SPLAT_RWLOCK_TEST6_DESC,
+		      SPLAT_RWLOCK_TEST6_ID, splat_rwlock_test6);
+
+	return sub;
 }
 
 void
 splat_rwlock_fini(splat_subsystem_t *sub)
 {
-        ASSERT(sub);
-        SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST6_ID);
-        SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST5_ID);
-        SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST4_ID);
-        SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST3_ID);
-        SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST2_ID);
-        SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST1_ID);
-        kfree(sub);
+	ASSERT(sub);
+	SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST6_ID);
+	SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST5_ID);
+	SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST4_ID);
+	SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST3_ID);
+	SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST2_ID);
+	SPLAT_TEST_FINI(sub, SPLAT_RWLOCK_TEST1_ID);
+	kfree(sub);
 }
 
 int
 splat_rwlock_id(void) {
-        return SPLAT_SUBSYSTEM_RWLOCK;
+	return SPLAT_SUBSYSTEM_RWLOCK;
 }