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, 80 NULL, 0); 81 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 82 } else 83 break; 84 } while (1); 85 bar->b_destroying = 0; 86 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 87 88 *barrier = NULL; 89 if (pshared) 90 __thr_pshared_destroy(barrier); 91 else 92 free(bar); 93 return (0); 94 } 95 96 int 97 _pthread_barrier_init(pthread_barrier_t * __restrict barrier, 98 const pthread_barrierattr_t * __restrict attr, unsigned count) 99 { 100 pthread_barrier_t bar; 101 int pshared; 102 103 if (barrier == NULL || count == 0 || count > INT_MAX) 104 return (EINVAL); 105 106 if (attr == NULL || *attr == NULL || 107 (*attr)->pshared == PTHREAD_PROCESS_PRIVATE) { 108 bar = calloc(1, sizeof(struct pthread_barrier)); 109 if (bar == NULL) 110 return (ENOMEM); 111 *barrier = bar; 112 pshared = 0; 113 } else { 114 bar = __thr_pshared_offpage(barrier, 1); 115 if (bar == NULL) 116 return (EFAULT); 117 *barrier = THR_PSHARED_PTR; 118 pshared = 1; 119 } 120 121 _thr_umutex_init(&bar->b_lock); 122 _thr_ucond_init(&bar->b_cv); 123 if (pshared) { 124 bar->b_lock.m_flags |= USYNC_PROCESS_SHARED; 125 bar->b_cv.c_flags |= USYNC_PROCESS_SHARED; 126 } 127 bar->b_count = count; 128 return (0); 129 } 130 131 int 132 _pthread_barrier_wait(pthread_barrier_t *barrier) 133 { 134 struct pthread *curthread; 135 pthread_barrier_t bar; 136 int64_t cycle; 137 int ret; 138 139 if (barrier == NULL || *barrier == NULL) 140 return (EINVAL); 141 142 if (*barrier == THR_PSHARED_PTR) { 143 bar = __thr_pshared_offpage(barrier, 0); 144 if (bar == NULL) 145 return (EINVAL); 146 } else { 147 bar = *barrier; 148 } 149 curthread = _get_curthread(); 150 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 151 if (++bar->b_waiters == bar->b_count) { 152 /* Current thread is lastest thread */ 153 bar->b_waiters = 0; 154 bar->b_cycle++; 155 _thr_ucond_broadcast(&bar->b_cv); 156 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 157 ret = PTHREAD_BARRIER_SERIAL_THREAD; 158 } else { 159 cycle = bar->b_cycle; 160 bar->b_refcount++; 161 do { 162 _thr_ucond_wait(&bar->b_cv, &bar->b_lock, NULL, 163 NULL, 0); 164 THR_UMUTEX_LOCK(curthread, &bar->b_lock); 165 /* test cycle to avoid bogus wakeup */ 166 } while (cycle == bar->b_cycle); 167 if (--bar->b_refcount == 0 && bar->b_destroying) 168 _thr_ucond_broadcast(&bar->b_cv); 169 THR_UMUTEX_UNLOCK(curthread, &bar->b_lock); 170 ret = 0; 171 } 172 return (ret); 173 } 174