-/*****************************************************************************\
+/*
* 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).
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
- * For details, see <http://github.com/behlendorf/spl/>.
+ * 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
*
* 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>
-
-#ifdef DEBUG_SUBSYSTEM
-#undef DEBUG_SUBSYSTEM
-#endif
-
-#define DEBUG_SUBSYSTEM S_CONDVAR
+#include <sys/time.h>
+#include <linux/hrtimer.h>
void
__cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg)
{
- int flags = KM_SLEEP;
-
- ENTRY;
ASSERT(cvp);
- ASSERT(name);
+ ASSERT(name == NULL);
ASSERT(type == CV_DEFAULT);
ASSERT(arg == NULL);
cvp->cv_magic = CV_MAGIC;
init_waitqueue_head(&cvp->cv_event);
- spin_lock_init(&cvp->cv_lock);
+ init_waitqueue_head(&cvp->cv_destroy);
atomic_set(&cvp->cv_waiters, 0);
+ atomic_set(&cvp->cv_refs, 1);
cvp->cv_mutex = NULL;
- cvp->cv_name = NULL;
- cvp->cv_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;
+}
+EXPORT_SYMBOL(__cv_init);
- cvp->cv_name = kmem_alloc(cvp->cv_name_size, flags);
- if (cvp->cv_name)
- strcpy(cvp->cv_name, name);
+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);
+ }
- EXIT;
+ return (0);
}
-EXPORT_SYMBOL(__cv_init);
void
__cv_destroy(kcondvar_t *cvp)
{
- ENTRY;
ASSERT(cvp);
ASSERT(cvp->cv_magic == CV_MAGIC);
- spin_lock(&cvp->cv_lock);
- ASSERT(atomic_read(&cvp->cv_waiters) == 0);
- ASSERT(!waitqueue_active(&cvp->cv_event));
- if (cvp->cv_name)
- kmem_free(cvp->cv_name, cvp->cv_name_size);
+ 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);
- spin_unlock(&cvp->cv_lock);
- memset(cvp, CV_POISON, sizeof(*cvp));
- EXIT;
+ 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)
+cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state, int io)
{
DEFINE_WAIT(wait);
- ENTRY;
+ kmutex_t *m;
ASSERT(cvp);
- ASSERT(mp);
+ ASSERT(mp);
ASSERT(cvp->cv_magic == CV_MAGIC);
- spin_lock(&cvp->cv_lock);
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);
- spin_unlock(&cvp->cv_lock);
+ 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);
- schedule();
- mutex_enter(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);
+ }
- atomic_dec(&cvp->cv_waiters);
finish_wait(&cvp->cv_event, &wait);
- EXIT;
+ 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);
+ cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 0);
}
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);
+ cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0);
}
-EXPORT_SYMBOL(__cv_wait_interruptible);
+EXPORT_SYMBOL(__cv_wait_sig);
-/* 'expire_time' argument is an absolute wall clock time in jiffies.
+void
+__cv_wait_io(kcondvar_t *cvp, kmutex_t *mp)
+{
+ cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 1);
+}
+EXPORT_SYMBOL(__cv_wait_io);
+
+/*
+ * 'expire_time' argument is an absolute wall clock time in jiffies.
* Return value is time left (expire_time - now) or -1 if timeout occurred.
*/
-clock_t
-__cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time)
+static clock_t
+__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;
- ENTRY;
ASSERT(cvp);
- ASSERT(mp);
+ ASSERT(mp);
ASSERT(cvp->cv_magic == CV_MAGIC);
- spin_lock(&cvp->cv_lock);
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);
- spin_unlock(&cvp->cv_lock);
+ ASSERT(m == NULL || m == mp);
/* XXX - Does not handle jiffie wrap properly */
time_left = expire_time - jiffies;
- if (time_left <= 0)
- RETURN(-1);
+ 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,
- TASK_UNINTERRUPTIBLE);
+ 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);
- atomic_dec(&cvp->cv_waiters);
+ /* 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);
- RETURN(time_left > 0 ? time_left : -1);
+ /*
+ * 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));
}
EXPORT_SYMBOL(__cv_timedwait);
+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));
+}
+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, now;
+ ktime_t ktime_left;
+
+ 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);
+
+ now = gethrtime();
+ time_left = expire_time - now;
+ if (time_left <= 0) {
+ 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
+ * 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;
+ }
+
+ ASSERT(!(flag & CALLOUT_FLAG_ABSOLUTE));
+ /* get abs expire time */
+ 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)
{
- ENTRY;
ASSERT(cvp);
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);
- EXIT;
+ atomic_dec(&cvp->cv_refs);
}
EXPORT_SYMBOL(__cv_signal);
{
ASSERT(cvp);
ASSERT(cvp->cv_magic == CV_MAGIC);
- ENTRY;
+ 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);
- EXIT;
+ atomic_dec(&cvp->cv_refs);
}
EXPORT_SYMBOL(__cv_broadcast);
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