1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2003 David Xu <davidxu@freebsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 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 _Static_assert(sizeof(struct pthread_barrier) <= THR_PAGE_SIZE_MIN, 38 "pthread_barrier is too large for off-page"); 39 40 __weak_reference(_pthread_barrier_init, pthread_barrier_init); 41 __weak_reference(_pthread_barrier_wait, pthread_barrier_wait); 42 __weak_reference(_pthread_barrier_destroy, pthread_barrier_destroy); 43 44 int 45 _pthread_barrier_destroy(pthread_barrier_t *barrier) 46 { 47 pthread_barrier_t bar; 48 struct pthread *curthread; 49 int pshared; 50 51 if (barrier == NULL || *barrier == NULL) 52 return (EINVAL); 53 54 if (*barrier == THR_PSHARED_PTR) { 55 bar = __thr_pshared_offpage(barrier, 0); 56 if (bar == NULL) { 57 *barrier = NULL; 58 return (0); 59 } 60 pshared = 1; 61 } else { 62 bar = *barrier; 63 pshared = 0; 64 } 65 curthread = _get_curthread(); 66 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 67 if (bar->b_destroying) { 68 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 69 return (EBUSY); 70 } 71 bar->b_destroying = 1; 72 do { 73 if (bar->b_waiters > 0) { 74 bar->b_destroying = 0; 75 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 76 return (EBUSY); 77 } 78 if (bar->b_refcount != 0) { 79 _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 0); 80 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 81 } else 82 break; 83 } while (1); 84 bar->b_destroying = 0; 85 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 86 87 *barrier = NULL; 88 if (pshared) 89 __thr_pshared_destroy(barrier); 90 else 91 free(bar); 92 return (0); 93 } 94 95 int 96 _pthread_barrier_init(pthread_barrier_t * __restrict barrier, 97 const pthread_barrierattr_t * __restrict attr, unsigned count) 98 { 99 pthread_barrier_t bar; 100 int pshared; 101 102 if (barrier == NULL || count == 0 || count > INT_MAX) 103 return (EINVAL); 104 105 if (attr == NULL || *attr == NULL || 106 (*attr)->pshared == PTHREAD_PROCESS_PRIVATE) { 107 bar = calloc(1, sizeof(struct pthread_barrier)); 108 if (bar == NULL) 109 return (ENOMEM); 110 *barrier = bar; 111 pshared = 0; 112 } else { 113 bar = __thr_pshared_offpage(barrier, 1); 114 if (bar == NULL) 115 return (EFAULT); 116 *barrier = THR_PSHARED_PTR; 117 pshared = 1; 118 } 119 120 _thr_umutex_init(&bar->b_lock); 121 _thr_ucond_init(&bar->b_cv); 122 if (pshared) { 123 bar->b_lock.m_flags |= USYNC_PROCESS_SHARED; 124 bar->b_cv.c_flags |= USYNC_PROCESS_SHARED; 125 } 126 bar->b_count = count; 127 return (0); 128 } 129 130 int 131 _pthread_barrier_wait(pthread_barrier_t *barrier) 132 { 133 struct pthread *curthread; 134 pthread_barrier_t bar; 135 int64_t cycle; 136 int ret; 137 138 if (barrier == NULL || *barrier == NULL) 139 return (EINVAL); 140 141 if (*barrier == THR_PSHARED_PTR) { 142 bar = __thr_pshared_offpage(barrier, 0); 143 if (bar == NULL) 144 return (EINVAL); 145 } else { 146 bar = *barrier; 147 } 148 curthread = _get_curthread(); 149 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 150 if (++bar->b_waiters == bar->b_count) { 151 /* Current thread is lastest thread */ 152 bar->b_waiters = 0; 153 bar->b_cycle++; 154 _thr_ucond_broadcast(&bar->b_cv); 155 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 156 ret = PTHREAD_BARRIER_SERIAL_THREAD; 157 } else { 158 cycle = bar->b_cycle; 159 bar->b_refcount++; 160 do { 161 _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 0); 162 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 163 /* test cycle to avoid bogus wakeup */ 164 } while (cycle == bar->b_cycle); 165 if (--bar->b_refcount == 0 && bar->b_destroying) 166 _thr_ucond_broadcast(&bar->b_cv); 167 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 168 ret = 0; 169 } 170 return (ret); 171 } 172