-/*****************************************************************************\
+/*
* 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).
*
* 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>
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 (1);
}
- return 0;
+ return (0);
}
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(mp);
ASSERT(cvp->cv_magic == CV_MAGIC);
ASSERT(mutex_owned(mp));
atomic_inc(&cvp->cv_refs);
- if (cvp->cv_mutex == NULL)
- cvp->cv_mutex = mp;
-
+ m = ACCESS_ONCE(cvp->cv_mutex);
+ if (!m)
+ m = xchg(&cvp->cv_mutex, mp);
/* Ensure the same mutex is used by all callers */
- ASSERT(cvp->cv_mutex == mp);
+ 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
+ /*
+ * 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. */
+ * race where 'cvp->cv_waiters > 0' but the list is empty.
+ */
mutex_exit(mp);
if (io)
io_schedule();
else
schedule();
- mutex_enter(mp);
/* 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
EXPORT_SYMBOL(__cv_wait);
void
-__cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp)
+__cv_wait_sig(kcondvar_t *cvp, kmutex_t *mp)
{
cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0);
}
-EXPORT_SYMBOL(__cv_wait_interruptible);
+EXPORT_SYMBOL(__cv_wait_sig);
void
__cv_wait_io(kcondvar_t *cvp, kmutex_t *mp)
}
EXPORT_SYMBOL(__cv_wait_io);
-/* 'expire_time' argument is an absolute wall clock time in jiffies.
+/*
+ * '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)
+__cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time,
+ int state)
{
DEFINE_WAIT(wait);
+ kmutex_t *m;
clock_t time_left;
ASSERT(cvp);
- ASSERT(mp);
+ ASSERT(mp);
ASSERT(cvp->cv_magic == CV_MAGIC);
ASSERT(mutex_owned(mp));
atomic_inc(&cvp->cv_refs);
- if (cvp->cv_mutex == NULL)
- cvp->cv_mutex = mp;
-
+ m = ACCESS_ONCE(cvp->cv_mutex);
+ if (!m)
+ m = xchg(&cvp->cv_mutex, mp);
/* Ensure the same mutex is used by all callers */
- ASSERT(cvp->cv_mutex == mp);
+ ASSERT(m == NULL || m == mp);
/* XXX - Does not handle jiffie wrap properly */
time_left = expire_time - jiffies;
if (time_left <= 0) {
+ /* XXX - doesn't reset cv_mutex */
atomic_dec(&cvp->cv_refs);
return (-1);
}
prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
atomic_inc(&cvp->cv_waiters);
- /* Mutex should be dropped after prepare_to_wait() this
+ /*
+ * 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. */
+ * 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)) {
+ /*
+ * 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);
+ 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)
+__cv_timedwait_sig(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
{
- return __cv_timedwait_common(cvp, mp, exp_time, TASK_INTERRUPTIBLE);
+ return (__cv_timedwait_common(cvp, mp, exp_time, TASK_INTERRUPTIBLE));
}
-EXPORT_SYMBOL(__cv_timedwait_interruptible);
+EXPORT_SYMBOL(__cv_timedwait_sig);
/*
- *'expire_time' argument is an absolute clock time in nanoseconds.
+ * '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)
+__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, now;
unsigned long time_left_us;
ASSERT(mutex_owned(mp));
atomic_inc(&cvp->cv_refs);
- if (cvp->cv_mutex == NULL)
- cvp->cv_mutex = mp;
-
+ m = ACCESS_ONCE(cvp->cv_mutex);
+ if (!m)
+ m = xchg(&cvp->cv_mutex, mp);
/* Ensure the same mutex is used by all callers */
- ASSERT(cvp->cv_mutex == mp);
+ ASSERT(m == NULL || m == mp);
now = gethrtime();
time_left = expire_time - now;
prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
atomic_inc(&cvp->cv_waiters);
- /* Mutex should be dropped after prepare_to_wait() this
+ /*
+ * 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. */
+ * 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 */
+ /*
+ * Allow a 100 us range to give kernel an opportunity to coalesce
+ * interrupts
+ */
usleep_range(time_left_us, time_left_us + 100);
- mutex_enter(mp);
/* 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 ? time_left : -1);
}
* Compatibility wrapper for the cv_timedwait_hires() Illumos interface.
*/
clock_t
-cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim,
- hrtime_t res, int flag)
+cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim, hrtime_t res,
+ int flag)
{
if (res > 1) {
/*
if (!(flag & CALLOUT_FLAG_ABSOLUTE))
tim += gethrtime();
- return __cv_timedwait_hires(cvp, mp, tim, TASK_UNINTERRUPTIBLE);
+ return (__cv_timedwait_hires(cvp, mp, tim, TASK_UNINTERRUPTIBLE));
}
EXPORT_SYMBOL(cv_timedwait_hires);
ASSERT(cvp->cv_magic == CV_MAGIC);
atomic_inc(&cvp->cv_refs);
- /* All waiters are added with WQ_FLAG_EXCLUSIVE so only one
+ /*
+ * 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. */
+ * the wait queue to ensure we don't race waking up processes.
+ */
if (atomic_read(&cvp->cv_waiters) > 0)
wake_up(&cvp->cv_event);
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. */
+ /*
+ * 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);
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