posix/src/pbarrierwait.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup POSIXAPI
0007  *
0008  * @brief Wait at a Barrier
0009  */
0010
0011 /*
0012  *  COPYRIGHT (c) 1989-2007.
0013  *  On-Line Applications Research Corporation (OAR).
0014  *
0015  *  Copyright (c) 2017 embedded brains GmbH & Co. KG
0016  *
0017  * Redistribution and use in source and binary forms, with or without
0018  * modification, are permitted provided that the following conditions
0019  * are met:
0020  * 1. Redistributions of source code must retain the above copyright
0021  *    notice, this list of conditions and the following disclaimer.
0022  * 2. Redistributions in binary form must reproduce the above copyright
0023  *    notice, this list of conditions and the following disclaimer in the
0024  *    documentation and/or other materials provided with the distribution.
0025  *
0026  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0027  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0028  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0029  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0030  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0031  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0032  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0033  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0034  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0035  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0036  * POSSIBILITY OF SUCH DAMAGE.
0037  */
0038
0039 #ifdef HAVE_CONFIG_H
0040 #include "config.h"
0041 #endif
0042
0043 #include <rtems/posix/barrierimpl.h>
0044 #include <rtems/posix/posixapi.h>
0045
0046 int pthread_barrier_wait( pthread_barrier_t *_barrier )
0047 {
0048   POSIX_Barrier_Control *barrier;
0049   Thread_queue_Context   queue_context;
0050   Thread_Control        *executing;
0051   unsigned int           waiting_threads;
0052
0053   POSIX_BARRIER_VALIDATE_OBJECT( _barrier );
0054
0055   barrier = _POSIX_Barrier_Get( _barrier );
0056
0057   executing = _POSIX_Barrier_Queue_acquire( barrier, &queue_context );
0058   waiting_threads = barrier->waiting_threads;
0059   ++waiting_threads;
0060
0061   if ( waiting_threads == barrier->count ) {
0062     barrier->waiting_threads = 0;
0063     _Thread_queue_Flush_critical(
0064       &barrier->Queue.Queue,
0065       POSIX_BARRIER_TQ_OPERATIONS,
0066       _Thread_queue_Flush_default_filter,
0067       &queue_context
0068     );
0069     return PTHREAD_BARRIER_SERIAL_THREAD;
0070   } else {
0071     barrier->waiting_threads = waiting_threads;
0072     _Thread_queue_Context_set_thread_state(
0073       &queue_context,
0074       STATES_WAITING_FOR_BARRIER
0075     );
0076     _Thread_queue_Context_set_enqueue_do_nothing_extra( &queue_context );
0077     _Thread_queue_Enqueue(
0078       &barrier->Queue.Queue,
0079       POSIX_BARRIER_TQ_OPERATIONS,
0080       executing,
0081       &queue_context
0082     );
0083     return 0;
0084   }
0085 }