112 lines
2.8 KiB
C
112 lines
2.8 KiB
C
/*
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* Copyright 2008-2013 Various Authors
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* Copyright 2004 Timo Hirvonen
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "locking.h"
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#include "debug.h"
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#include <string.h>
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#include <stdatomic.h>
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#include <stdbool.h>
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struct fifo_waiter {
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struct fifo_waiter * _Atomic next;
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pthread_cond_t cond;
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};
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pthread_t main_thread;
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void cmus_mutex_lock(pthread_mutex_t *mutex)
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{
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int rc = pthread_mutex_lock(mutex);
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if (unlikely(rc))
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BUG("error locking mutex: %s\n", strerror(rc));
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}
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void cmus_mutex_unlock(pthread_mutex_t *mutex)
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{
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int rc = pthread_mutex_unlock(mutex);
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if (unlikely(rc))
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BUG("error unlocking mutex: %s\n", strerror(rc));
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}
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void cmus_rwlock_rdlock(pthread_rwlock_t *lock)
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{
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int rc = pthread_rwlock_rdlock(lock);
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if (unlikely(rc))
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BUG("error locking mutex: %s\n", strerror(rc));
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}
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void cmus_rwlock_wrlock(pthread_rwlock_t *lock)
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{
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int rc = pthread_rwlock_wrlock(lock);
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if (unlikely(rc))
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BUG("error locking mutex: %s\n", strerror(rc));
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}
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void cmus_rwlock_unlock(pthread_rwlock_t *lock)
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{
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int rc = pthread_rwlock_unlock(lock);
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if (unlikely(rc))
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BUG("error unlocking mutex: %s\n", strerror(rc));
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}
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void fifo_mutex_lock(struct fifo_mutex *fifo)
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{
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struct fifo_waiter self = {
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.cond = PTHREAD_COND_INITIALIZER,
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.next = ATOMIC_VAR_INIT(NULL),
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};
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struct fifo_waiter *old_tail = atomic_exchange_explicit(&fifo->tail, &self,
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memory_order_relaxed);
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if (old_tail)
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atomic_store_explicit(&old_tail->next, &self, memory_order_release);
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cmus_mutex_lock(&fifo->mutex);
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if (old_tail) {
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while (fifo->head != &self)
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pthread_cond_wait(&self.cond, &fifo->mutex);
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pthread_cond_destroy(&self.cond);
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}
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struct fifo_waiter *self_addr = &self;
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bool was_tail = atomic_compare_exchange_strong_explicit(&fifo->tail, &self_addr,
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NULL, memory_order_relaxed, memory_order_relaxed);
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struct fifo_waiter *next = NULL;
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if (!was_tail) {
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while (!(next = atomic_load_explicit(&self.next, memory_order_consume)))
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;
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}
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fifo->head = next;
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}
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void fifo_mutex_unlock(struct fifo_mutex *fifo)
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{
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if (fifo->head)
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pthread_cond_signal(&fifo->head->cond);
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cmus_mutex_unlock(&fifo->mutex);
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}
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void fifo_mutex_yield(struct fifo_mutex *fifo)
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{
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if (fifo->head || atomic_load_explicit(&fifo->tail, memory_order_relaxed)) {
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fifo_mutex_unlock(fifo);
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fifo_mutex_lock(fifo);
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}
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}
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