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/*-
* Copyright (c) 2003 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, 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.
*
* $FreeBSD$
*/
#include <errno.h>
#include <stdlib.h>
#include <pthread.h>
#include "thr_private.h"
__weak_reference(_pthread_barrier_init, pthread_barrier_init);
__weak_reference(_pthread_barrier_wait, pthread_barrier_wait);
__weak_reference(_pthread_barrier_destroy, pthread_barrier_destroy);
int
_pthread_barrier_destroy(pthread_barrier_t *barrier)
{
pthread_barrier_t bar;
if (barrier == NULL || *barrier == NULL)
return (EINVAL);
bar = *barrier;
if (bar->b_waiters > 0)
return (EBUSY);
*barrier = NULL;
free(bar);
return (0);
}
int
_pthread_barrier_init(pthread_barrier_t *barrier,
const pthread_barrierattr_t *attr, int count)
{
pthread_barrier_t bar;
if (barrier == NULL || count <= 0)
return (EINVAL);
bar = malloc(sizeof(struct pthread_barrier));
if (bar == NULL)
return (ENOMEM);
_thr_umtx_init(&bar->b_lock);
bar->b_cycle = 0;
bar->b_waiters = 0;
bar->b_count = count;
*barrier = bar;
return (0);
}
int
_pthread_barrier_wait(pthread_barrier_t *barrier)
{
struct pthread *curthread = _get_curthread();
pthread_barrier_t bar;
long cycle;
int ret;
if (barrier == NULL || *barrier == NULL)
return (EINVAL);
bar = *barrier;
THR_UMTX_LOCK(curthread, &bar->b_lock);
if (++bar->b_waiters == bar->b_count) {
/* Current thread is lastest thread */
bar->b_waiters = 0;
bar->b_cycle++;
_thr_umtx_wake(&bar->b_cycle, bar->b_count - 1);
THR_UMTX_UNLOCK(curthread, &bar->b_lock);
ret = PTHREAD_BARRIER_SERIAL_THREAD;
} else {
cycle = bar->b_cycle;
THR_UMTX_UNLOCK(curthread, &bar->b_lock);
do {
_thr_umtx_wait(&bar->b_cycle, cycle, NULL);
/* test cycle to avoid bogus wakeup */
} while (cycle == bar->b_cycle);
ret = 0;
}
return (ret);
}
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