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 * $FreeBSD$ 27 */ 28 29 #include "namespace.h" 30 #include <errno.h> 31 #include <stdlib.h> 32 #include <pthread.h> 33 #include "un-namespace.h" 34 35 #include "thr_private.h" 36 37 __weak_reference(_pthread_barrier_init, pthread_barrier_init); 38 __weak_reference(_pthread_barrier_wait, pthread_barrier_wait); 39 __weak_reference(_pthread_barrier_destroy, pthread_barrier_destroy); 40 41 int 42 _pthread_barrier_destroy(pthread_barrier_t *barrier) 43 { 44 pthread_barrier_t bar; 45 struct pthread *curthread; 46 47 if (barrier == NULL || *barrier == NULL) 48 return (EINVAL); 49 50 curthread = _get_curthread(); 51 bar = *barrier; 52 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 53 if (bar->b_destroying) { 54 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 55 return (EBUSY); 56 } 57 bar->b_destroying = 1; 58 do { 59 if (bar->b_waiters > 0) { 60 bar->b_destroying = 0; 61 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 62 return (EBUSY); 63 } 64 if (bar->b_refcount != 0) { 65 _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 0); 66 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 67 } else 68 break; 69 } while (1); 70 bar->b_destroying = 0; 71 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 72 73 *barrier = NULL; 74 free(bar); 75 return (0); 76 } 77 78 int 79 _pthread_barrier_init(pthread_barrier_t *barrier, 80 const pthread_barrierattr_t *attr, unsigned count) 81 { 82 pthread_barrier_t bar; 83 84 (void)attr; 85 86 if (barrier == NULL || count <= 0) 87 return (EINVAL); 88 89 bar = malloc(sizeof(struct pthread_barrier)); 90 if (bar == NULL) 91 return (ENOMEM); 92 93 _thr_umutex_init(&bar->b_lock); 94 _thr_ucond_init(&bar->b_cv); 95 bar->b_cycle = 0; 96 bar->b_waiters = 0; 97 bar->b_count = count; 98 bar->b_refcount = 0; 99 *barrier = bar; 100 101 return (0); 102 } 103 104 int 105 _pthread_barrier_wait(pthread_barrier_t *barrier) 106 { 107 struct pthread *curthread = _get_curthread(); 108 pthread_barrier_t bar; 109 int64_t cycle; 110 int ret; 111 112 if (barrier == NULL || *barrier == NULL) 113 return (EINVAL); 114 115 bar = *barrier; 116 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 117 if (++bar->b_waiters == bar->b_count) { 118 /* Current thread is lastest thread */ 119 bar->b_waiters = 0; 120 bar->b_cycle++; 121 _thr_ucond_broadcast(&bar->b_cv); 122 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 123 ret = PTHREAD_BARRIER_SERIAL_THREAD; 124 } else { 125 cycle = bar->b_cycle; 126 bar->b_refcount++; 127 do { 128 _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 0); 129 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 130 /* test cycle to avoid bogus wakeup */ 131 } while (cycle == bar->b_cycle); 132 if (--bar->b_refcount == 0 && bar->b_destroying) 133 _thr_ucond_broadcast(&bar->b_cv); 134 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 135 ret = 0; 136 } 137 return (ret); 138 } 139