freebsd-dev/lib/libthr/thread/thr_pspinlock.c
Pedro F. Giffuni 5e53a4f90f lib: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-26 02:00:33 +00:00

156 lines
4.2 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2003 David Xu <davidxu@freebsd.org>
* Copyright (c) 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 <errno.h>
#include <stdlib.h>
#include <pthread.h>
#include "un-namespace.h"
#include "thr_private.h"
_Static_assert(sizeof(struct pthread_spinlock) <= PAGE_SIZE,
"pthread_spinlock is too large for off-page");
#define SPIN_COUNT 100000
__weak_reference(_pthread_spin_init, pthread_spin_init);
__weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
__weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
__weak_reference(_pthread_spin_lock, pthread_spin_lock);
__weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
int
_pthread_spin_init(pthread_spinlock_t *lock, int pshared)
{
struct pthread_spinlock *lck;
if (lock == NULL)
return (EINVAL);
if (pshared == PTHREAD_PROCESS_PRIVATE) {
lck = malloc(sizeof(struct pthread_spinlock));
if (lck == NULL)
return (ENOMEM);
*lock = lck;
} else if (pshared == PTHREAD_PROCESS_SHARED) {
lck = __thr_pshared_offpage(lock, 1);
if (lck == NULL)
return (EFAULT);
*lock = THR_PSHARED_PTR;
} else {
return (EINVAL);
}
_thr_umutex_init(&lck->s_lock);
return (0);
}
int
_pthread_spin_destroy(pthread_spinlock_t *lock)
{
void *l;
int ret;
if (lock == NULL || *lock == NULL) {
ret = EINVAL;
} else if (*lock == THR_PSHARED_PTR) {
l = __thr_pshared_offpage(lock, 0);
if (l != NULL)
__thr_pshared_destroy(l);
ret = 0;
} else {
free(*lock);
*lock = NULL;
ret = 0;
}
return (ret);
}
int
_pthread_spin_trylock(pthread_spinlock_t *lock)
{
struct pthread_spinlock *lck;
if (lock == NULL || *lock == NULL)
return (EINVAL);
lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
if (lck == NULL)
return (EINVAL);
return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock));
}
int
_pthread_spin_lock(pthread_spinlock_t *lock)
{
struct pthread *curthread;
struct pthread_spinlock *lck;
int count;
if (lock == NULL)
return (EINVAL);
lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
if (lck == NULL)
return (EINVAL);
curthread = _get_curthread();
count = SPIN_COUNT;
while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) {
while (lck->s_lock.m_owner) {
if (!_thr_is_smp) {
_pthread_yield();
} else {
CPU_SPINWAIT;
if (--count <= 0) {
count = SPIN_COUNT;
_pthread_yield();
}
}
}
}
return (0);
}
int
_pthread_spin_unlock(pthread_spinlock_t *lock)
{
struct pthread_spinlock *lck;
if (lock == NULL)
return (EINVAL);
lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
if (lck == NULL)
return (EINVAL);
return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock));
}