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: src/lib/libpthread/thread/thr_barrier.c,v 1.1 2003/09/04 14:06:43 davidxu Exp $ 27 * $DragonFly: src/lib/libthread_xu/thread/thr_barrier.c,v 1.6 2006/04/06 13:03:09 davidxu Exp $ 28 */ 29 30 #include "namespace.h" 31 #include <machine/tls.h> 32 33 #include <errno.h> 34 #include <stdlib.h> 35 #include <pthread.h> 36 #include "un-namespace.h" 37 38 #include "thr_private.h" 39 40 int 41 _pthread_barrier_destroy(pthread_barrier_t *barrier) 42 { 43 pthread_barrier_t bar; 44 45 if (barrier == NULL || *barrier == NULL) 46 return (EINVAL); 47 48 bar = *barrier; 49 if (bar->b_waiters > 0) 50 return (EBUSY); 51 *barrier = NULL; 52 free(bar); 53 return (0); 54 } 55 56 int 57 _pthread_barrier_init(pthread_barrier_t *barrier, 58 const pthread_barrierattr_t *attr __unused, unsigned count) 59 { 60 pthread_barrier_t bar; 61 62 if (barrier == NULL || count <= 0) 63 return (EINVAL); 64 65 bar = malloc(sizeof(struct pthread_barrier)); 66 if (bar == NULL) 67 return (ENOMEM); 68 69 _thr_umtx_init(&bar->b_lock); 70 bar->b_cycle = 0; 71 bar->b_waiters = 0; 72 bar->b_count = count; 73 *barrier = bar; 74 75 return (0); 76 } 77 78 int 79 _pthread_barrier_wait(pthread_barrier_t *barrier) 80 { 81 struct pthread *curthread = tls_get_curthread(); 82 pthread_barrier_t bar; 83 long cycle; 84 int ret; 85 86 if (barrier == NULL || *barrier == NULL) 87 return (EINVAL); 88 89 bar = *barrier; 90 THR_UMTX_LOCK(curthread, &bar->b_lock); 91 if (++bar->b_waiters == bar->b_count) { 92 /* Current thread is lastest thread */ 93 bar->b_waiters = 0; 94 bar->b_cycle++; 95 _thr_umtx_wake(&bar->b_cycle, bar->b_count); 96 THR_UMTX_UNLOCK(curthread, &bar->b_lock); 97 ret = PTHREAD_BARRIER_SERIAL_THREAD; 98 } else { 99 cycle = bar->b_cycle; 100 THR_UMTX_UNLOCK(curthread, &bar->b_lock); 101 do { 102 _thr_umtx_wait(&bar->b_cycle, cycle, NULL, 0); 103 /* test cycle to avoid bogus wakeup */ 104 } while (cycle == bar->b_cycle); 105 ret = 0; 106 } 107 return (ret); 108 } 109 110 __strong_reference(_pthread_barrier_init, pthread_barrier_init); 111 __strong_reference(_pthread_barrier_wait, pthread_barrier_wait); 112 __strong_reference(_pthread_barrier_destroy, pthread_barrier_destroy); 113