thr_barrier.c revision 156611
1/*- 2 * Copyright (c) 2003 David Xu <davidxu@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: head/lib/libkse/thread/thr_barrier.c 156611 2006-03-13 00:59:51Z deischen $ 27 */ 28 29#include <errno.h> 30#include <stdlib.h> 31#include "namespace.h" 32#include <pthread.h> 33#include "un-namespace.h" 34#include "thr_private.h" 35 36LT10_COMPAT_PRIVATE(_pthread_barrier_init); 37LT10_COMPAT_DEFAULT(pthread_barrier_init); 38LT10_COMPAT_PRIVATE(_pthread_barrier_wait); 39LT10_COMPAT_DEFAULT(pthread_barrier_wait); 40LT10_COMPAT_PRIVATE(_pthread_barrier_destroy); 41LT10_COMPAT_DEFAULT(pthread_barrier_destroy); 42 43__weak_reference(_pthread_barrier_init, pthread_barrier_init); 44__weak_reference(_pthread_barrier_wait, pthread_barrier_wait); 45__weak_reference(_pthread_barrier_destroy, pthread_barrier_destroy); 46 47int 48_pthread_barrier_destroy(pthread_barrier_t *barrier) 49{ 50 pthread_barrier_t bar; 51 int ret, ret2; 52 53 if (barrier == NULL || *barrier == NULL) 54 return (EINVAL); 55 56 bar = *barrier; 57 if (bar->b_waiters > 0) 58 return (EBUSY); 59 *barrier = NULL; 60 ret = _pthread_mutex_destroy(&bar->b_lock); 61 ret2 = _pthread_cond_destroy(&bar->b_cond); 62 free(bar); 63 return (ret ? ret : ret2); 64} 65 66int 67_pthread_barrier_init(pthread_barrier_t *barrier, 68 const pthread_barrierattr_t *attr, int count) 69{ 70 pthread_barrier_t bar; 71 int ret; 72 73 if (barrier == NULL || count <= 0) 74 return (EINVAL); 75 76 bar = malloc(sizeof(struct pthread_barrier)); 77 if (bar == NULL) 78 return (ENOMEM); 79 80 if ((ret = _pthread_mutex_init(&bar->b_lock, NULL)) != 0) { 81 free(bar); 82 return (ret); 83 } 84 85 if ((ret = _pthread_cond_init(&bar->b_cond, NULL)) != 0) { 86 _pthread_mutex_destroy(&bar->b_lock); 87 free(bar); 88 return (ret); 89 } 90 91 bar->b_waiters = 0; 92 bar->b_count = count; 93 bar->b_generation = 0; 94 *barrier = bar; 95 96 return (0); 97} 98 99int 100_pthread_barrier_wait(pthread_barrier_t *barrier) 101{ 102 int ret, gen; 103 pthread_barrier_t bar; 104 105 if (barrier == NULL || *barrier == NULL) 106 return (EINVAL); 107 108 bar = *barrier; 109 if ((ret = _pthread_mutex_lock(&bar->b_lock)) != 0) 110 return (ret); 111 112 if (++bar->b_waiters == bar->b_count) { 113 /* Current thread is lastest thread */ 114 bar->b_generation++; 115 bar->b_waiters = 0; 116 ret = _pthread_cond_broadcast(&bar->b_cond); 117 if (ret == 0) 118 ret = PTHREAD_BARRIER_SERIAL_THREAD; 119 } else { 120 gen = bar->b_generation; 121 do { 122 ret = _pthread_cond_wait( 123 &bar->b_cond, &bar->b_lock); 124 /* test generation to avoid bogus wakeup */ 125 } while (ret == 0 && gen == bar->b_generation); 126 } 127 _pthread_mutex_unlock(&bar->b_lock); 128 return (ret); 129} 130