mirror_zfs/module/spl/spl-condvar.c
Brian Behlendorf e5b9b344c7 Refactor existing code
This change introduces no functional changes to the memory management
interfaces.  It only restructures the existing codes by separating the
kmem, vmem, and kmem cache implementations in the separate source and
header files.

Splitting this functionality in to separate files required the addition
of spl_vmem_{init,fini}() and spl_kmem_cache_{initi,fini}() functions.

Additionally, several minor changes to the #include's were required to
accommodate the removal of extraneous header from kmem.h.

But again, while large this patch introduces no functional changes.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:08 -08:00

318 lines
8.3 KiB
C

/*****************************************************************************\
* 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>
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);
ASSERT(cvp);
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;
/* 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);
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)) {
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
finish_wait(&cvp->cv_event, &wait);
atomic_dec(&cvp->cv_refs);
}
void
__cv_wait(kcondvar_t *cvp, kmutex_t *mp)
{
cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 0);
}
EXPORT_SYMBOL(__cv_wait);
void
__cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp)
{
cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0);
}
EXPORT_SYMBOL(__cv_wait_interruptible);
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);
clock_t time_left;
ASSERT(cvp);
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;
/* 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) {
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);
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);
atomic_dec(&cvp->cv_refs);
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_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);
/*
*'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);
hrtime_t time_left, now;
unsigned long time_left_us;
ASSERT(cvp);
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;
/* Ensure the same mutex is used by all callers */
ASSERT(cvp->cv_mutex == mp);
now = gethrtime();
time_left = expire_time - now;
if (time_left <= 0) {
atomic_dec(&cvp->cv_refs);
return (-1);
}
time_left_us = time_left / NSEC_PER_USEC;
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 */
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)) {
cvp->cv_mutex = NULL;
wake_up(&cvp->cv_destroy);
}
finish_wait(&cvp->cv_event, &wait);
atomic_dec(&cvp->cv_refs);
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)
{
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, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(cv_timedwait_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);