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thr_mutex.c
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thr_mutex.c
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/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* Copyright (c) 2006 David Xu <davidxu@freebsd.org>.
* Copyright (c) 2015, 2016 The FreeBSD Foundation
*
* All rights reserved.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <pthread.h>
#include <pthread_np.h>
#include "un-namespace.h"
#include "thr_private.h"
_Static_assert(sizeof(struct pthread_mutex) <= PAGE_SIZE,
"pthread_mutex is too large for off-page");
/*
* For adaptive mutexes, how many times to spin doing trylock2
* before entering the kernel to block
*/
#define MUTEX_ADAPTIVE_SPINS 2000
/*
* Prototypes
*/
int __pthread_mutex_timedlock(pthread_mutex_t * __restrict mutex,
const struct timespec * __restrict abstime);
int _pthread_mutex_getspinloops_np(pthread_mutex_t *mutex, int *count);
int _pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count);
int __pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count);
int _pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count);
int _pthread_mutex_getyieldloops_np(pthread_mutex_t *mutex, int *count);
int __pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count);
static int mutex_self_trylock(pthread_mutex_t);
static int mutex_self_lock(pthread_mutex_t,
const struct timespec *abstime);
static int mutex_unlock_common(struct pthread_mutex *, bool, int *);
static int mutex_lock_sleep(struct pthread *, pthread_mutex_t,
const struct timespec *);
static void mutex_init_robust(struct pthread *curthread);
static int mutex_qidx(struct pthread_mutex *m);
static bool is_robust_mutex(struct pthread_mutex *m);
static bool is_pshared_mutex(struct pthread_mutex *m);
__weak_reference(__Tthr_mutex_init, pthread_mutex_init);
__weak_reference(__Tthr_mutex_init, __pthread_mutex_init);
__strong_reference(__Tthr_mutex_init, _pthread_mutex_init);
__weak_reference(__Tthr_mutex_lock, pthread_mutex_lock);
__weak_reference(__Tthr_mutex_lock, __pthread_mutex_lock);
__strong_reference(__Tthr_mutex_lock, _pthread_mutex_lock);
__weak_reference(__pthread_mutex_timedlock, pthread_mutex_timedlock);
__strong_reference(__pthread_mutex_timedlock, _pthread_mutex_timedlock);
__weak_reference(__Tthr_mutex_trylock, pthread_mutex_trylock);
__weak_reference(__Tthr_mutex_trylock, __pthread_mutex_trylock);
__strong_reference(__Tthr_mutex_trylock, _pthread_mutex_trylock);
__weak_reference(_Tthr_mutex_consistent, pthread_mutex_consistent);
__weak_reference(_Tthr_mutex_consistent, _pthread_mutex_consistent);
__strong_reference(_Tthr_mutex_consistent, __pthread_mutex_consistent);
/* Single underscore versions provided for libc internal usage: */
/* No difference between libc and application usage of these: */
__weak_reference(_thr_mutex_destroy, pthread_mutex_destroy);
__weak_reference(_thr_mutex_destroy, _pthread_mutex_destroy);
__weak_reference(_thr_mutex_unlock, pthread_mutex_unlock);
__weak_reference(_thr_mutex_unlock, _pthread_mutex_unlock);
__weak_reference(_pthread_mutex_getprioceiling, pthread_mutex_getprioceiling);
__weak_reference(_pthread_mutex_setprioceiling, pthread_mutex_setprioceiling);
__weak_reference(__pthread_mutex_setspinloops_np, pthread_mutex_setspinloops_np);
__strong_reference(__pthread_mutex_setspinloops_np, _pthread_mutex_setspinloops_np);
__weak_reference(_pthread_mutex_getspinloops_np, pthread_mutex_getspinloops_np);
__weak_reference(__pthread_mutex_setyieldloops_np, pthread_mutex_setyieldloops_np);
__strong_reference(__pthread_mutex_setyieldloops_np, _pthread_mutex_setyieldloops_np);
__weak_reference(_pthread_mutex_getyieldloops_np, pthread_mutex_getyieldloops_np);
__weak_reference(_pthread_mutex_isowned_np, pthread_mutex_isowned_np);
static void
mutex_init_link(struct pthread_mutex *m)
{
#if defined(_PTHREADS_INVARIANTS)
m->m_qe.tqe_prev = NULL;
m->m_qe.tqe_next = NULL;
m->m_pqe.tqe_prev = NULL;
m->m_pqe.tqe_next = NULL;
#endif
}
static void
mutex_assert_is_owned(struct pthread_mutex *m __unused)
{
#if defined(_PTHREADS_INVARIANTS)
if (__predict_false(m->m_qe.tqe_prev == NULL))
PANIC("mutex %p own %#x is not on list %p %p",
m, m->m_lock.m_owner, m->m_qe.tqe_prev, m->m_qe.tqe_next);
#endif
}
static void
mutex_assert_not_owned(struct pthread *curthread __unused,
struct pthread_mutex *m __unused)
{
#if defined(_PTHREADS_INVARIANTS)
if (__predict_false(m->m_qe.tqe_prev != NULL ||
m->m_qe.tqe_next != NULL))
PANIC("mutex %p own %#x is on list %p %p",
m, m->m_lock.m_owner, m->m_qe.tqe_prev, m->m_qe.tqe_next);
if (__predict_false(is_robust_mutex(m) &&
(m->m_lock.m_rb_lnk != 0 || m->m_rb_prev != NULL ||
(is_pshared_mutex(m) && curthread->robust_list ==
(uintptr_t)&m->m_lock) ||
(!is_pshared_mutex(m) && curthread->priv_robust_list ==
(uintptr_t)&m->m_lock))))
PANIC(
"mutex %p own %#x is on robust linkage %p %p head %p phead %p",
m, m->m_lock.m_owner, (void *)m->m_lock.m_rb_lnk,
m->m_rb_prev, (void *)curthread->robust_list,
(void *)curthread->priv_robust_list);
#endif
}
static bool
is_pshared_mutex(struct pthread_mutex *m)
{
return ((m->m_lock.m_flags & USYNC_PROCESS_SHARED) != 0);
}
static bool
is_robust_mutex(struct pthread_mutex *m)
{
return ((m->m_lock.m_flags & UMUTEX_ROBUST) != 0);
}
int
_mutex_enter_robust(struct pthread *curthread, struct pthread_mutex *m)
{
#if defined(_PTHREADS_INVARIANTS)
if (__predict_false(curthread->inact_mtx != 0))
PANIC("inact_mtx enter");
#endif
if (!is_robust_mutex(m))
return (0);
mutex_init_robust(curthread);
curthread->inact_mtx = (uintptr_t)&m->m_lock;
return (1);
}
void
_mutex_leave_robust(struct pthread *curthread, struct pthread_mutex *m __unused)
{
#if defined(_PTHREADS_INVARIANTS)
if (__predict_false(curthread->inact_mtx != (uintptr_t)&m->m_lock))
PANIC("inact_mtx leave");
#endif
curthread->inact_mtx = 0;
}
static int
mutex_check_attr(const struct pthread_mutex_attr *attr)
{
if (attr->m_type < PTHREAD_MUTEX_ERRORCHECK ||
attr->m_type >= PTHREAD_MUTEX_TYPE_MAX)
return (EINVAL);
if (attr->m_protocol < PTHREAD_PRIO_NONE ||
attr->m_protocol > PTHREAD_PRIO_PROTECT)
return (EINVAL);
return (0);
}
static void
mutex_init_robust(struct pthread *curthread)
{
struct umtx_robust_lists_params rb;
if (curthread == NULL)
curthread = _get_curthread();
if (curthread->robust_inited)
return;
rb.robust_list_offset = (uintptr_t)&curthread->robust_list;
rb.robust_priv_list_offset = (uintptr_t)&curthread->priv_robust_list;
rb.robust_inact_offset = (uintptr_t)&curthread->inact_mtx;
_umtx_op(NULL, UMTX_OP_ROBUST_LISTS, sizeof(rb), &rb, NULL);
curthread->robust_inited = 1;
}
static void
mutex_init_body(struct pthread_mutex *pmutex,
const struct pthread_mutex_attr *attr)
{
pmutex->m_flags = attr->m_type;
pmutex->m_count = 0;
pmutex->m_spinloops = 0;
pmutex->m_yieldloops = 0;
mutex_init_link(pmutex);
switch (attr->m_protocol) {
case PTHREAD_PRIO_NONE:
pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
pmutex->m_lock.m_flags = 0;
break;
case PTHREAD_PRIO_INHERIT:
pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
pmutex->m_lock.m_flags = UMUTEX_PRIO_INHERIT;
break;
case PTHREAD_PRIO_PROTECT:
pmutex->m_lock.m_owner = UMUTEX_CONTESTED;
pmutex->m_lock.m_flags = UMUTEX_PRIO_PROTECT;
pmutex->m_lock.m_ceilings[0] = attr->m_ceiling;
break;
}
if (attr->m_pshared == PTHREAD_PROCESS_SHARED)
pmutex->m_lock.m_flags |= USYNC_PROCESS_SHARED;
if (attr->m_robust == PTHREAD_MUTEX_ROBUST) {
mutex_init_robust(NULL);
pmutex->m_lock.m_flags |= UMUTEX_ROBUST;
}
if (PMUTEX_TYPE(pmutex->m_flags) == PTHREAD_MUTEX_ADAPTIVE_NP) {
pmutex->m_spinloops =
_thr_spinloops ? _thr_spinloops: MUTEX_ADAPTIVE_SPINS;
pmutex->m_yieldloops = _thr_yieldloops;
}
}
static int
mutex_init(pthread_mutex_t *mutex,
const struct pthread_mutex_attr *mutex_attr,
void *(calloc_cb)(size_t, size_t))
{
const struct pthread_mutex_attr *attr;
struct pthread_mutex *pmutex;
int error;
if (mutex_attr == NULL) {
attr = &_pthread_mutexattr_default;
} else {
attr = mutex_attr;
error = mutex_check_attr(attr);
if (error != 0)
return (error);
}
if ((pmutex = (pthread_mutex_t)
calloc_cb(1, sizeof(struct pthread_mutex))) == NULL)
return (ENOMEM);
mutex_init_body(pmutex, attr);
*mutex = pmutex;
return (0);
}
static int
init_static(struct pthread *thread, pthread_mutex_t *mutex)
{
int ret;
THR_LOCK_ACQUIRE(thread, &_mutex_static_lock);
if (*mutex == THR_MUTEX_INITIALIZER)
ret = mutex_init(mutex, &_pthread_mutexattr_default,
__thr_calloc);
else if (*mutex == THR_ADAPTIVE_MUTEX_INITIALIZER)
ret = mutex_init(mutex, &_pthread_mutexattr_adaptive_default,
__thr_calloc);
else
ret = 0;
THR_LOCK_RELEASE(thread, &_mutex_static_lock);
return (ret);
}
static void
set_inherited_priority(struct pthread *curthread, struct pthread_mutex *m)
{
struct pthread_mutex *m2;
m2 = TAILQ_LAST(&curthread->mq[mutex_qidx(m)], mutex_queue);
if (m2 != NULL)
m->m_lock.m_ceilings[1] = m2->m_lock.m_ceilings[0];
else
m->m_lock.m_ceilings[1] = -1;
}
static void
shared_mutex_init(struct pthread_mutex *pmtx, const struct
pthread_mutex_attr *mutex_attr)
{
static const struct pthread_mutex_attr foobar_mutex_attr = {
.m_type = PTHREAD_MUTEX_DEFAULT,
.m_protocol = PTHREAD_PRIO_NONE,
.m_ceiling = 0,
.m_pshared = PTHREAD_PROCESS_SHARED,
.m_robust = PTHREAD_MUTEX_STALLED,
};
bool done;
/*
* Hack to allow multiple pthread_mutex_init() calls on the
* same process-shared mutex. We rely on kernel allocating
* zeroed offpage for the mutex, i.e. the
* PMUTEX_INITSTAGE_ALLOC value must be zero.
*/
for (done = false; !done;) {
switch (pmtx->m_ps) {
case PMUTEX_INITSTAGE_DONE:
atomic_thread_fence_acq();
done = true;
break;
case PMUTEX_INITSTAGE_ALLOC:
if (atomic_cmpset_int(&pmtx->m_ps,
PMUTEX_INITSTAGE_ALLOC, PMUTEX_INITSTAGE_BUSY)) {
if (mutex_attr == NULL)
mutex_attr = &foobar_mutex_attr;
mutex_init_body(pmtx, mutex_attr);
atomic_store_rel_int(&pmtx->m_ps,
PMUTEX_INITSTAGE_DONE);
done = true;
}
break;
case PMUTEX_INITSTAGE_BUSY:
_pthread_yield();
break;
default:
PANIC("corrupted offpage");
break;
}
}
}
int
__Tthr_mutex_init(pthread_mutex_t * __restrict mutex,
const pthread_mutexattr_t * __restrict mutex_attr)
{
struct pthread_mutex *pmtx;
int ret;
_thr_check_init();
if (mutex_attr != NULL) {
ret = mutex_check_attr(*mutex_attr);
if (ret != 0)
return (ret);
}
if (mutex_attr == NULL ||
(*mutex_attr)->m_pshared == PTHREAD_PROCESS_PRIVATE) {
__thr_malloc_init();
return (mutex_init(mutex, mutex_attr ? *mutex_attr : NULL,
__thr_calloc));
}
pmtx = __thr_pshared_offpage(__DECONST(void *, mutex), 1);
if (pmtx == NULL)
return (EFAULT);
*mutex = THR_PSHARED_PTR;
shared_mutex_init(pmtx, *mutex_attr);
return (0);
}
/* This function is used internally by malloc. */
int
_pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
void *(calloc_cb)(size_t, size_t))
{
static const struct pthread_mutex_attr attr = {
.m_type = PTHREAD_MUTEX_NORMAL,
.m_protocol = PTHREAD_PRIO_NONE,
.m_ceiling = 0,
.m_pshared = PTHREAD_PROCESS_PRIVATE,
.m_robust = PTHREAD_MUTEX_STALLED,
};
int ret;
ret = mutex_init(mutex, &attr, calloc_cb);
if (ret == 0)
(*mutex)->m_flags |= PMUTEX_FLAG_PRIVATE;
return (ret);
}
/*
* Fix mutex ownership for child process.
*
* Process private mutex ownership is transmitted from the forking
* thread to the child process.
*
* Process shared mutex should not be inherited because owner is
* forking thread which is in parent process, they are removed from
* the owned mutex list.
*/
static void
queue_fork(struct pthread *curthread, struct mutex_queue *q,
struct mutex_queue *qp, uint bit)
{
struct pthread_mutex *m;
TAILQ_INIT(q);
TAILQ_FOREACH(m, qp, m_pqe) {
TAILQ_INSERT_TAIL(q, m, m_qe);
m->m_lock.m_owner = TID(curthread) | bit;
}
}
void
_mutex_fork(struct pthread *curthread)
{
queue_fork(curthread, &curthread->mq[TMQ_NORM],
&curthread->mq[TMQ_NORM_PRIV], 0);
queue_fork(curthread, &curthread->mq[TMQ_NORM_PP],
&curthread->mq[TMQ_NORM_PP_PRIV], UMUTEX_CONTESTED);
queue_fork(curthread, &curthread->mq[TMQ_ROBUST_PP],
&curthread->mq[TMQ_ROBUST_PP_PRIV], UMUTEX_CONTESTED);
curthread->robust_list = 0;
}
int
_thr_mutex_destroy(pthread_mutex_t *mutex)
{
pthread_mutex_t m, m1;
int ret;
m = *mutex;
if (m < THR_MUTEX_DESTROYED) {
ret = 0;
} else if (m == THR_MUTEX_DESTROYED) {
ret = EINVAL;
} else {
if (m == THR_PSHARED_PTR) {
m1 = __thr_pshared_offpage(mutex, 0);
if (m1 != NULL) {
if ((uint32_t)m1->m_lock.m_owner !=
UMUTEX_RB_OWNERDEAD) {
mutex_assert_not_owned(
_get_curthread(), m1);
}
__thr_pshared_destroy(mutex);
}
*mutex = THR_MUTEX_DESTROYED;
return (0);
}
if (PMUTEX_OWNER_ID(m) != 0 &&
(uint32_t)m->m_lock.m_owner != UMUTEX_RB_NOTRECOV) {
ret = EBUSY;
} else {
*mutex = THR_MUTEX_DESTROYED;
mutex_assert_not_owned(_get_curthread(), m);
__thr_free(m);
ret = 0;
}
}
return (ret);
}
static int
mutex_qidx(struct pthread_mutex *m)
{
if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
return (TMQ_NORM);
return (is_robust_mutex(m) ? TMQ_ROBUST_PP : TMQ_NORM_PP);
}
/*
* Both enqueue_mutex() and dequeue_mutex() operate on the
* thread-private linkage of the locked mutexes and on the robust
* linkage.
*
* Robust list, as seen by kernel, must be consistent even in the case
* of thread termination at arbitrary moment. Since either enqueue or
* dequeue for list walked by kernel consists of rewriting a single
* forward pointer, it is safe. On the other hand, rewrite of the
* back pointer is not atomic WRT the forward one, but kernel does not
* care.
*/
static void
enqueue_mutex(struct pthread *curthread, struct pthread_mutex *m,
int error)
{
struct pthread_mutex *m1;
uintptr_t *rl;
int qidx;
/* Add to the list of owned mutexes: */
if (error != EOWNERDEAD)
mutex_assert_not_owned(curthread, m);
qidx = mutex_qidx(m);
TAILQ_INSERT_TAIL(&curthread->mq[qidx], m, m_qe);
if (!is_pshared_mutex(m))
TAILQ_INSERT_TAIL(&curthread->mq[qidx + 1], m, m_pqe);
if (is_robust_mutex(m)) {
rl = is_pshared_mutex(m) ? &curthread->robust_list :
&curthread->priv_robust_list;
m->m_rb_prev = NULL;
if (*rl != 0) {
m1 = __containerof((void *)*rl,
struct pthread_mutex, m_lock);
m->m_lock.m_rb_lnk = (uintptr_t)&m1->m_lock;
m1->m_rb_prev = m;
} else {
m1 = NULL;
m->m_lock.m_rb_lnk = 0;
}
*rl = (uintptr_t)&m->m_lock;
}
}
static void
dequeue_mutex(struct pthread *curthread, struct pthread_mutex *m)
{
struct pthread_mutex *mp, *mn;
int qidx;
mutex_assert_is_owned(m);
qidx = mutex_qidx(m);
if (is_robust_mutex(m)) {
mp = m->m_rb_prev;
if (mp == NULL) {
if (is_pshared_mutex(m)) {
curthread->robust_list = m->m_lock.m_rb_lnk;
} else {
curthread->priv_robust_list =
m->m_lock.m_rb_lnk;
}
} else {
mp->m_lock.m_rb_lnk = m->m_lock.m_rb_lnk;
}
if (m->m_lock.m_rb_lnk != 0) {
mn = __containerof((void *)m->m_lock.m_rb_lnk,
struct pthread_mutex, m_lock);
mn->m_rb_prev = m->m_rb_prev;
}
m->m_lock.m_rb_lnk = 0;
m->m_rb_prev = NULL;
}
TAILQ_REMOVE(&curthread->mq[qidx], m, m_qe);
if (!is_pshared_mutex(m))
TAILQ_REMOVE(&curthread->mq[qidx + 1], m, m_pqe);
if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) != 0)
set_inherited_priority(curthread, m);
mutex_init_link(m);
}
static int
check_and_init_mutex(pthread_mutex_t *mutex, struct pthread_mutex **m)
{
int ret;
*m = *mutex;
ret = 0;
if (*m == THR_PSHARED_PTR) {
*m = __thr_pshared_offpage(mutex, 0);
if (*m == NULL)
ret = EINVAL;
else
shared_mutex_init(*m, NULL);
} else if (__predict_false(*m <= THR_MUTEX_DESTROYED)) {
if (*m == THR_MUTEX_DESTROYED) {
ret = EINVAL;
} else {
ret = init_static(_get_curthread(), mutex);
if (ret == 0)
*m = *mutex;
}
}
return (ret);
}
int
__Tthr_mutex_trylock(pthread_mutex_t *mutex)
{
struct pthread *curthread;
struct pthread_mutex *m;
uint32_t id;
int ret, robust;
ret = check_and_init_mutex(mutex, &m);
if (ret != 0)
return (ret);
curthread = _get_curthread();
id = TID(curthread);
if (m->m_flags & PMUTEX_FLAG_PRIVATE)
THR_CRITICAL_ENTER(curthread);
robust = _mutex_enter_robust(curthread, m);
ret = _thr_umutex_trylock(&m->m_lock, id);
if (__predict_true(ret == 0) || ret == EOWNERDEAD) {
enqueue_mutex(curthread, m, ret);
if (ret == EOWNERDEAD)
m->m_lock.m_flags |= UMUTEX_NONCONSISTENT;
} else if (PMUTEX_OWNER_ID(m) == id) {
ret = mutex_self_trylock(m);
} /* else {} */
if (robust)
_mutex_leave_robust(curthread, m);
if (ret != 0 && ret != EOWNERDEAD &&
(m->m_flags & PMUTEX_FLAG_PRIVATE) != 0)
THR_CRITICAL_LEAVE(curthread);
return (ret);
}
static int
mutex_lock_sleep(struct pthread *curthread, struct pthread_mutex *m,
const struct timespec *abstime)
{
uint32_t id, owner;
int count, ret;
id = TID(curthread);
if (PMUTEX_OWNER_ID(m) == id)
return (mutex_self_lock(m, abstime));
/*
* For adaptive mutexes, spin for a bit in the expectation
* that if the application requests this mutex type then
* the lock is likely to be released quickly and it is
* faster than entering the kernel
*/
if (__predict_false((m->m_lock.m_flags & (UMUTEX_PRIO_PROTECT |
UMUTEX_PRIO_INHERIT | UMUTEX_ROBUST | UMUTEX_NONCONSISTENT)) != 0))
goto sleep_in_kernel;
if (!_thr_is_smp)
goto yield_loop;
count = m->m_spinloops;
while (count--) {
owner = m->m_lock.m_owner;
if ((owner & ~UMUTEX_CONTESTED) == 0) {
if (atomic_cmpset_acq_32(&m->m_lock.m_owner, owner,
id | owner)) {
ret = 0;
goto done;
}
}
CPU_SPINWAIT;
}
yield_loop:
count = m->m_yieldloops;
while (count--) {
_sched_yield();
owner = m->m_lock.m_owner;
if ((owner & ~UMUTEX_CONTESTED) == 0) {
if (atomic_cmpset_acq_32(&m->m_lock.m_owner, owner,
id | owner)) {
ret = 0;
goto done;
}
}
}
sleep_in_kernel:
if (abstime == NULL)
ret = __thr_umutex_lock(&m->m_lock, id);
else if (__predict_false(abstime->tv_nsec < 0 ||
abstime->tv_nsec >= 1000000000))
ret = EINVAL;
else
ret = __thr_umutex_timedlock(&m->m_lock, id, abstime);
done:
if (ret == 0 || ret == EOWNERDEAD) {
enqueue_mutex(curthread, m, ret);
if (ret == EOWNERDEAD)
m->m_lock.m_flags |= UMUTEX_NONCONSISTENT;
}
return (ret);
}
static inline int
mutex_lock_common(struct pthread_mutex *m, const struct timespec *abstime,
bool cvattach, bool rb_onlist)
{
struct pthread *curthread;
int ret, robust;
robust = 0; /* pacify gcc */
curthread = _get_curthread();
if (!cvattach && m->m_flags & PMUTEX_FLAG_PRIVATE)
THR_CRITICAL_ENTER(curthread);
if (!rb_onlist)
robust = _mutex_enter_robust(curthread, m);
ret = _thr_umutex_trylock2(&m->m_lock, TID(curthread));
if (ret == 0 || ret == EOWNERDEAD) {
enqueue_mutex(curthread, m, ret);
if (ret == EOWNERDEAD)
m->m_lock.m_flags |= UMUTEX_NONCONSISTENT;
} else {
ret = mutex_lock_sleep(curthread, m, abstime);
}
if (!rb_onlist && robust)
_mutex_leave_robust(curthread, m);
if (ret != 0 && ret != EOWNERDEAD &&
(m->m_flags & PMUTEX_FLAG_PRIVATE) != 0 && !cvattach)
THR_CRITICAL_LEAVE(curthread);
return (ret);
}
int
__Tthr_mutex_lock(pthread_mutex_t *mutex)
{
struct pthread_mutex *m;
int ret;
_thr_check_init();
ret = check_and_init_mutex(mutex, &m);
if (ret == 0)
ret = mutex_lock_common(m, NULL, false, false);
return (ret);
}
int
__pthread_mutex_timedlock(pthread_mutex_t * __restrict mutex,
const struct timespec * __restrict abstime)
{
struct pthread_mutex *m;
int ret;
_thr_check_init();
ret = check_and_init_mutex(mutex, &m);
if (ret == 0)
ret = mutex_lock_common(m, abstime, false, false);
return (ret);
}
int
_thr_mutex_unlock(pthread_mutex_t *mutex)
{
struct pthread_mutex *mp;
if (*mutex == THR_PSHARED_PTR) {
mp = __thr_pshared_offpage(mutex, 0);
if (mp == NULL)
return (EINVAL);
shared_mutex_init(mp, NULL);
} else {
mp = *mutex;
}
return (mutex_unlock_common(mp, false, NULL));
}
int
_mutex_cv_lock(struct pthread_mutex *m, int count, bool rb_onlist)
{
int error;
error = mutex_lock_common(m, NULL, true, rb_onlist);
if (error == 0 || error == EOWNERDEAD)
m->m_count = count;
return (error);
}
int
_mutex_cv_unlock(struct pthread_mutex *m, int *count, int *defer)
{
/*
* Clear the count in case this is a recursive mutex.
*/
*count = m->m_count;
m->m_count = 0;
(void)mutex_unlock_common(m, true, defer);
return (0);
}
int
_mutex_cv_attach(struct pthread_mutex *m, int count)
{
struct pthread *curthread;
curthread = _get_curthread();
enqueue_mutex(curthread, m, 0);
m->m_count = count;
return (0);
}
int
_mutex_cv_detach(struct pthread_mutex *mp, int *recurse)
{
struct pthread *curthread;
int deferred, error;
curthread = _get_curthread();
if ((error = _mutex_owned(curthread, mp)) != 0)
return (error);
/*
* Clear the count in case this is a recursive mutex.
*/
*recurse = mp->m_count;
mp->m_count = 0;
dequeue_mutex(curthread, mp);
/* Will this happen in real-world ? */
if ((mp->m_flags & PMUTEX_FLAG_DEFERRED) != 0) {
deferred = 1;
mp->m_flags &= ~PMUTEX_FLAG_DEFERRED;
} else
deferred = 0;
if (deferred) {
_thr_wake_all(curthread->defer_waiters,
curthread->nwaiter_defer);
curthread->nwaiter_defer = 0;
}
return (0);
}
static int
mutex_self_trylock(struct pthread_mutex *m)
{
int ret;
switch (PMUTEX_TYPE(m->m_flags)) {
case PTHREAD_MUTEX_ERRORCHECK:
case PTHREAD_MUTEX_NORMAL:
case PTHREAD_MUTEX_ADAPTIVE_NP:
ret = EBUSY;
break;
case PTHREAD_MUTEX_RECURSIVE:
/* Increment the lock count: */
if (m->m_count + 1 > 0) {
m->m_count++;
ret = 0;
} else
ret = EAGAIN;
break;
default:
/* Trap invalid mutex types; */
ret = EINVAL;
}
return (ret);
}
static int
mutex_self_lock(struct pthread_mutex *m, const struct timespec *abstime)
{
struct timespec ts1, ts2;
int ret;
switch (PMUTEX_TYPE(m->m_flags)) {
case PTHREAD_MUTEX_ERRORCHECK:
case PTHREAD_MUTEX_ADAPTIVE_NP:
if (abstime) {
if (abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
abstime->tv_nsec >= 1000000000) {
ret = EINVAL;
} else {
clock_gettime(CLOCK_REALTIME, &ts1);
TIMESPEC_SUB(&ts2, abstime, &ts1);
__sys_nanosleep(&ts2, NULL);
ret = ETIMEDOUT;
}
} else {
/*
* POSIX specifies that mutexes should return
* EDEADLK if a recursive lock is detected.
*/
ret = EDEADLK;
}
break;
case PTHREAD_MUTEX_NORMAL:
/*
* What SS2 define as a 'normal' mutex. Intentionally
* deadlock on attempts to get a lock you already own.
*/
ret = 0;
if (abstime) {
if (abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
abstime->tv_nsec >= 1000000000) {
ret = EINVAL;
} else {
clock_gettime(CLOCK_REALTIME, &ts1);
TIMESPEC_SUB(&ts2, abstime, &ts1);
__sys_nanosleep(&ts2, NULL);
ret = ETIMEDOUT;
}
} else {
ts1.tv_sec = 30;
ts1.tv_nsec = 0;
for (;;)
__sys_nanosleep(&ts1, NULL);
}
break;
case PTHREAD_MUTEX_RECURSIVE:
/* Increment the lock count: */
if (m->m_count + 1 > 0) {
m->m_count++;
ret = 0;
} else
ret = EAGAIN;
break;
default:
/* Trap invalid mutex types; */
ret = EINVAL;
}
return (ret);
}
static int
mutex_unlock_common(struct pthread_mutex *m, bool cv, int *mtx_defer)
{
struct pthread *curthread;
uint32_t id;
int deferred, error, private, robust;
if (__predict_false(m <= THR_MUTEX_DESTROYED)) {
if (m == THR_MUTEX_DESTROYED)
return (EINVAL);
return (EPERM);
}
curthread = _get_curthread();
id = TID(curthread);
/*
* Check if the running thread is not the owner of the mutex.
*/
if (__predict_false(PMUTEX_OWNER_ID(m) != id))
return (EPERM);
error = 0;
private = (m->m_flags & PMUTEX_FLAG_PRIVATE) != 0;
if (__predict_false(PMUTEX_TYPE(m->m_flags) ==
PTHREAD_MUTEX_RECURSIVE && m->m_count > 0)) {
m->m_count--;
} else {
if ((m->m_flags & PMUTEX_FLAG_DEFERRED) != 0) {
deferred = 1;
m->m_flags &= ~PMUTEX_FLAG_DEFERRED;
} else
deferred = 0;
robust = _mutex_enter_robust(curthread, m);
dequeue_mutex(curthread, m);
error = _thr_umutex_unlock2(&m->m_lock, id, mtx_defer);
if (deferred) {
if (mtx_defer == NULL) {
_thr_wake_all(curthread->defer_waiters,
curthread->nwaiter_defer);
curthread->nwaiter_defer = 0;
} else
*mtx_defer = 1;
}
if (robust)
_mutex_leave_robust(curthread, m);