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/*****************************************************************************\
* 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 <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://github.com/behlendorf/spl/>.
*
* 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 <spl-debug.h>
#ifdef SS_DEBUG_SUBSYS
#undef SS_DEBUG_SUBSYS
#endif
#define SS_DEBUG_SUBSYS SS_CONDVAR
void
__cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg)
{
int flags = KM_SLEEP;
SENTRY;
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);
cvp->cv_mutex = NULL;
/* 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;
SEXIT;
}
EXPORT_SYMBOL(__cv_init);
static int
cv_destroy_wakeup(kcondvar_t *cvp)
{
if ((waitqueue_active(&cvp->cv_event)) ||
(atomic_read(&cvp->cv_waiters) > 0))
return 0;
return 1;
}
void
__cv_destroy(kcondvar_t *cvp)
{
SENTRY;
ASSERT(cvp);
ASSERT(cvp->cv_magic == CV_MAGIC);
/* Block until all waiters have woken */
while (cv_destroy_wakeup(cvp) == 0)
wait_event_timeout(cvp->cv_destroy, cv_destroy_wakeup(cvp), 1);
ASSERT(cvp->cv_mutex == NULL);
ASSERT(atomic_read(&cvp->cv_waiters) == 0);
ASSERT(!waitqueue_active(&cvp->cv_event));
SEXIT;
}
EXPORT_SYMBOL(__cv_destroy);
static void
cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state)
{
DEFINE_WAIT(wait);
SENTRY;
ASSERT(cvp);
ASSERT(mp);
ASSERT(cvp->cv_magic == CV_MAGIC);
ASSERT(mutex_owned(mp));
if (cvp->cv_mutex == NULL)
cvp->cv_mutex = mp;
/* Ensure the same mutex is used by all callers */
ASSERT(cvp->cv_mutex == 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);
schedule();
mutex_enter(mp);
/* No more waiters a different mutex could be used */
if (atomic_dec_and_test(&cvp->cv_waiters)) {
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
finish_wait(&cvp->cv_event, &wait);
SEXIT;
}
void
__cv_wait(kcondvar_t *cvp, kmutex_t *mp)
{
cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(__cv_wait);
void
__cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp)
{
cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE);
}
EXPORT_SYMBOL(__cv_wait_interruptible);
/* '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)
{
DEFINE_WAIT(wait);
clock_t time_left;
SENTRY;
ASSERT(cvp);
ASSERT(mp);
ASSERT(cvp->cv_magic == CV_MAGIC);
ASSERT(mutex_owned(mp));
if (cvp->cv_mutex == NULL)
cvp->cv_mutex = mp;
/* Ensure the same mutex is used by all callers */
ASSERT(cvp->cv_mutex == mp);
/* XXX - Does not handle jiffie wrap properly */
time_left = expire_time - jiffies;
if (time_left <= 0)
SRETURN(-1);
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);
time_left = schedule_timeout(time_left);
mutex_enter(mp);
/* No more waiters a different mutex could be used */
if (atomic_dec_and_test(&cvp->cv_waiters)) {
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
finish_wait(&cvp->cv_event, &wait);
SRETURN(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);
}
EXPORT_SYMBOL(__cv_timedwait);
clock_t
__cv_timedwait_interruptible(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
{
return __cv_timedwait_common(cvp, mp, exp_time, TASK_INTERRUPTIBLE);
}
EXPORT_SYMBOL(__cv_timedwait_interruptible);
void
__cv_signal(kcondvar_t *cvp)
{
SENTRY;
ASSERT(cvp);
ASSERT(cvp->cv_magic == CV_MAGIC);
/* 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);
SEXIT;
}
EXPORT_SYMBOL(__cv_signal);
void
__cv_broadcast(kcondvar_t *cvp)
{
ASSERT(cvp);
ASSERT(cvp->cv_magic == CV_MAGIC);
SENTRY;
/* 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);
SEXIT;
}
EXPORT_SYMBOL(__cv_broadcast);
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