freebsd-skq/lib/libthr/thread/thr_umtx.c
Eric van Gyzen 8e402f34b9 libthr: const-ify two variables
Make the default umutex and urwlock initializers const,
because they can be, and as a microoptimization.

MFC after:	5 days
Sponsored by:	Dell Inc.
2016-01-13 22:34:55 +00:00

344 lines
7.9 KiB
C

/*
* Copyright (c) 2005 David Xu <davidxu@freebsd.org>
* All rights reserved.
*
* 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 unmodified, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*
* $FreeBSD$
*
*/
#include "thr_private.h"
#include "thr_umtx.h"
#ifndef HAS__UMTX_OP_ERR
int _umtx_op_err(void *obj, int op, u_long val, void *uaddr, void *uaddr2)
{
if (_umtx_op(obj, op, val, uaddr, uaddr2) == -1)
return (errno);
return (0);
}
#endif
void
_thr_umutex_init(struct umutex *mtx)
{
static const struct umutex default_mtx = DEFAULT_UMUTEX;
*mtx = default_mtx;
}
void
_thr_urwlock_init(struct urwlock *rwl)
{
static const struct urwlock default_rwl = DEFAULT_URWLOCK;
*rwl = default_rwl;
}
int
__thr_umutex_lock(struct umutex *mtx, uint32_t id)
{
uint32_t owner;
if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
for (;;) {
/* wait in kernel */
_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);
owner = mtx->m_owner;
if ((owner & ~UMUTEX_CONTESTED) == 0 &&
atomic_cmpset_acq_32(&mtx->m_owner, owner, id|owner))
return (0);
}
}
return _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
}
#define SPINLOOPS 1000
int
__thr_umutex_lock_spin(struct umutex *mtx, uint32_t id)
{
uint32_t owner;
if (!_thr_is_smp)
return __thr_umutex_lock(mtx, id);
if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
for (;;) {
int count = SPINLOOPS;
while (count--) {
owner = mtx->m_owner;
if ((owner & ~UMUTEX_CONTESTED) == 0) {
if (atomic_cmpset_acq_32(
&mtx->m_owner,
owner, id|owner)) {
return (0);
}
}
CPU_SPINWAIT;
}
/* wait in kernel */
_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);
}
}
return _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
}
int
__thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
const struct timespec *abstime)
{
struct _umtx_time *tm_p, timeout;
size_t tm_size;
uint32_t owner;
int ret;
if (abstime == NULL) {
tm_p = NULL;
tm_size = 0;
} else {
timeout._clockid = CLOCK_REALTIME;
timeout._flags = UMTX_ABSTIME;
timeout._timeout = *abstime;
tm_p = &timeout;
tm_size = sizeof(timeout);
}
for (;;) {
if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
/* wait in kernel */
ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0,
(void *)tm_size, __DECONST(void *, tm_p));
/* now try to lock it */
owner = mtx->m_owner;
if ((owner & ~UMUTEX_CONTESTED) == 0 &&
atomic_cmpset_acq_32(&mtx->m_owner, owner, id|owner))
return (0);
} else {
ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0,
(void *)tm_size, __DECONST(void *, tm_p));
if (ret == 0)
break;
}
if (ret == ETIMEDOUT)
break;
}
return (ret);
}
int
__thr_umutex_unlock(struct umutex *mtx, uint32_t id)
{
return _umtx_op_err(mtx, UMTX_OP_MUTEX_UNLOCK, 0, 0, 0);
}
int
__thr_umutex_trylock(struct umutex *mtx)
{
return _umtx_op_err(mtx, UMTX_OP_MUTEX_TRYLOCK, 0, 0, 0);
}
int
__thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
uint32_t *oldceiling)
{
return _umtx_op_err(mtx, UMTX_OP_SET_CEILING, ceiling, oldceiling, 0);
}
int
_thr_umtx_wait(volatile long *mtx, long id, const struct timespec *timeout)
{
if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
timeout->tv_nsec <= 0)))
return (ETIMEDOUT);
return _umtx_op_err(__DEVOLATILE(void *, mtx), UMTX_OP_WAIT, id, 0,
__DECONST(void*, timeout));
}
int
_thr_umtx_wait_uint(volatile u_int *mtx, u_int id, const struct timespec *timeout, int shared)
{
if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
timeout->tv_nsec <= 0)))
return (ETIMEDOUT);
return _umtx_op_err(__DEVOLATILE(void *, mtx),
shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id, 0,
__DECONST(void*, timeout));
}
int
_thr_umtx_timedwait_uint(volatile u_int *mtx, u_int id, int clockid,
const struct timespec *abstime, int shared)
{
struct _umtx_time *tm_p, timeout;
size_t tm_size;
if (abstime == NULL) {
tm_p = NULL;
tm_size = 0;
} else {
timeout._clockid = clockid;
timeout._flags = UMTX_ABSTIME;
timeout._timeout = *abstime;
tm_p = &timeout;
tm_size = sizeof(timeout);
}
return _umtx_op_err(__DEVOLATILE(void *, mtx),
shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id,
(void *)tm_size, __DECONST(void *, tm_p));
}
int
_thr_umtx_wake(volatile void *mtx, int nr_wakeup, int shared)
{
return _umtx_op_err(__DEVOLATILE(void *, mtx), shared ? UMTX_OP_WAKE : UMTX_OP_WAKE_PRIVATE,
nr_wakeup, 0, 0);
}
void
_thr_ucond_init(struct ucond *cv)
{
bzero(cv, sizeof(struct ucond));
}
int
_thr_ucond_wait(struct ucond *cv, struct umutex *m,
const struct timespec *timeout, int flags)
{
if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
timeout->tv_nsec <= 0))) {
struct pthread *curthread = _get_curthread();
_thr_umutex_unlock(m, TID(curthread));
return (ETIMEDOUT);
}
return _umtx_op_err(cv, UMTX_OP_CV_WAIT, flags,
m, __DECONST(void*, timeout));
}
int
_thr_ucond_signal(struct ucond *cv)
{
if (!cv->c_has_waiters)
return (0);
return _umtx_op_err(cv, UMTX_OP_CV_SIGNAL, 0, NULL, NULL);
}
int
_thr_ucond_broadcast(struct ucond *cv)
{
if (!cv->c_has_waiters)
return (0);
return _umtx_op_err(cv, UMTX_OP_CV_BROADCAST, 0, NULL, NULL);
}
int
__thr_rwlock_rdlock(struct urwlock *rwlock, int flags,
const struct timespec *tsp)
{
struct _umtx_time timeout, *tm_p;
size_t tm_size;
if (tsp == NULL) {
tm_p = NULL;
tm_size = 0;
} else {
timeout._timeout = *tsp;
timeout._flags = UMTX_ABSTIME;
timeout._clockid = CLOCK_REALTIME;
tm_p = &timeout;
tm_size = sizeof(timeout);
}
return _umtx_op_err(rwlock, UMTX_OP_RW_RDLOCK, flags, (void *)tm_size, tm_p);
}
int
__thr_rwlock_wrlock(struct urwlock *rwlock, const struct timespec *tsp)
{
struct _umtx_time timeout, *tm_p;
size_t tm_size;
if (tsp == NULL) {
tm_p = NULL;
tm_size = 0;
} else {
timeout._timeout = *tsp;
timeout._flags = UMTX_ABSTIME;
timeout._clockid = CLOCK_REALTIME;
tm_p = &timeout;
tm_size = sizeof(timeout);
}
return _umtx_op_err(rwlock, UMTX_OP_RW_WRLOCK, 0, (void *)tm_size, tm_p);
}
int
__thr_rwlock_unlock(struct urwlock *rwlock)
{
return _umtx_op_err(rwlock, UMTX_OP_RW_UNLOCK, 0, NULL, NULL);
}
void
_thr_rwl_rdlock(struct urwlock *rwlock)
{
int ret;
for (;;) {
if (_thr_rwlock_tryrdlock(rwlock, URWLOCK_PREFER_READER) == 0)
return;
ret = __thr_rwlock_rdlock(rwlock, URWLOCK_PREFER_READER, NULL);
if (ret == 0)
return;
if (ret != EINTR)
PANIC("rdlock error");
}
}
void
_thr_rwl_wrlock(struct urwlock *rwlock)
{
int ret;
for (;;) {
if (_thr_rwlock_trywrlock(rwlock) == 0)
return;
ret = __thr_rwlock_wrlock(rwlock, NULL);
if (ret == 0)
return;
if (ret != EINTR)
PANIC("wrlock error");
}
}
void
_thr_rwl_unlock(struct urwlock *rwlock)
{
if (_thr_rwlock_unlock(rwlock))
PANIC("unlock error");
}