108 lines
3.0 KiB
C
108 lines
3.0 KiB
C
/*-
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* Copyright (c) 2003 David Xu <davidxu@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include "thr_private.h"
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__weak_reference(_pthread_barrier_init, pthread_barrier_init);
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__weak_reference(_pthread_barrier_wait, pthread_barrier_wait);
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__weak_reference(_pthread_barrier_destroy, pthread_barrier_destroy);
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int
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_pthread_barrier_destroy(pthread_barrier_t *barrier)
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{
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pthread_barrier_t bar;
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if (barrier == NULL || *barrier == NULL)
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return (EINVAL);
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bar = *barrier;
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if (bar->b_waiters > 0)
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return (EBUSY);
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*barrier = NULL;
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free(bar);
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return (0);
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}
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int
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_pthread_barrier_init(pthread_barrier_t *barrier,
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const pthread_barrierattr_t *attr, int count)
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{
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pthread_barrier_t bar;
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if (barrier == NULL || count <= 0)
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return (EINVAL);
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bar = malloc(sizeof(struct pthread_barrier));
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if (bar == NULL)
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return (ENOMEM);
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_thr_umtx_init(&bar->b_lock);
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bar->b_cycle = 0;
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bar->b_waiters = 0;
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bar->b_count = count;
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*barrier = bar;
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return (0);
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}
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int
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_pthread_barrier_wait(pthread_barrier_t *barrier)
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{
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struct pthread *curthread = _get_curthread();
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pthread_barrier_t bar;
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long cycle;
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int ret;
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if (barrier == NULL || *barrier == NULL)
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return (EINVAL);
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bar = *barrier;
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THR_UMTX_LOCK(curthread, &bar->b_lock);
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if (++bar->b_waiters == bar->b_count) {
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/* Current thread is lastest thread */
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bar->b_waiters = 0;
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bar->b_cycle++;
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_thr_umtx_wake(&bar->b_cycle, bar->b_count - 1);
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THR_UMTX_UNLOCK(curthread, &bar->b_lock);
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ret = PTHREAD_BARRIER_SERIAL_THREAD;
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} else {
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cycle = bar->b_cycle;
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THR_UMTX_UNLOCK(curthread, &bar->b_lock);
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do {
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_thr_umtx_wait(&bar->b_cycle, cycle, NULL);
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/* test cycle to avoid bogus wakeup */
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} while (cycle == bar->b_cycle);
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ret = 0;
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}
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return (ret);
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}
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