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Diffstat (limited to 'src/thread/pthread_cond_broadcast.c')
-rw-r--r--src/thread/pthread_cond_broadcast.c41
1 files changed, 40 insertions, 1 deletions
diff --git a/src/thread/pthread_cond_broadcast.c b/src/thread/pthread_cond_broadcast.c
index dec91164..3daa7817 100644
--- a/src/thread/pthread_cond_broadcast.c
+++ b/src/thread/pthread_cond_broadcast.c
@@ -1,8 +1,47 @@
#include "pthread_impl.h"
+static void unlock(pthread_cond_t *c)
+{
+ a_dec(&c->_c_bcast);
+ if (c->_c_leavers) __wake(&c->_c_bcast, -1, 0);
+}
+
int pthread_cond_broadcast(pthread_cond_t *c)
{
+ pthread_mutex_t *m;
+ int w;
+
+ if (!c->_c_waiters) return 0;
+ a_inc(&c->_c_bcast);
+ if (!c->_c_waiters) {
+ unlock(c);
+ return 0;
+ }
+
a_store(&c->_c_block, 0);
- if (c->_c_waiters) __wake(&c->_c_block, -1, 0);
+
+ m = c->_c_mutex;
+
+ /* If mutex ptr is not available, simply wake all waiters. */
+ if (m == (void *)-1) {
+ unlock(c);
+ __wake(&c->_c_block, -1, 0);
+ return 0;
+ }
+
+ /* Move waiter count to the mutex */
+ for (;;) {
+ w = c->_c_waiters;
+ a_fetch_add(&m->_m_waiters, w);
+ if (a_cas(&c->_c_waiters, w, 0) == w) break;
+ a_fetch_add(&m->_m_waiters, -w);
+ }
+
+ /* Perform the futex requeue, waking one waiter if and only if
+ * the calling thread does not hold the mutex. */
+ __syscall(SYS_futex, &c->_c_block, FUTEX_REQUEUE,
+ m->_m_lock!=pthread_self()->tid, INT_MAX, &m->_m_lock);
+
+ unlock(c);
return 0;
}