+++ /dev/null
-/*
- * 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://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_sig(kcondvar_t *cvp, kmutex_t *mp)
-{
- cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0);
-}
-EXPORT_SYMBOL(__cv_wait_sig);
-
-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.
- */
-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;
-
- 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);
- 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));
-}
-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;
- 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);
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