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Diffstat (limited to 'src/thread/pthread_cond_timedwait.c')
-rw-r--r--src/thread/pthread_cond_timedwait.c44
1 files changed, 28 insertions, 16 deletions
diff --git a/src/thread/pthread_cond_timedwait.c b/src/thread/pthread_cond_timedwait.c
index 9616dd85..e9b5e2fc 100644
--- a/src/thread/pthread_cond_timedwait.c
+++ b/src/thread/pthread_cond_timedwait.c
@@ -7,17 +7,22 @@ struct cm {
static void unwait(pthread_cond_t *c, pthread_mutex_t *m)
{
- int w;
+ /* Removing a waiter is non-trivial if we could be using requeue
+ * based broadcast signals, due to mutex access issues, etc. */
- /* Cannot leave waiting status if there are any live broadcasters
- * which might be inspecting/using the mutex. */
- while ((w=c->_c_bcast)) __wait(&c->_c_bcast, &c->_c_leavers, w, 0);
+ if (c->_c_mutex == (void *)-1) {
+ a_dec(&c->_c_waiters);
+ return;
+ }
- /* If the waiter count is zero, it must be the case that the
- * caller's count has been moved to the mutex due to bcast. */
- do w = c->_c_waiters;
- while (w && a_cas(&c->_c_waiters, w, w-1)!=w);
- if (!w) a_dec(&m->_m_waiters);
+ while (a_swap(&c->_c_lock, 1))
+ __wait(&c->_c_lock, &c->_c_lockwait, 1, 1);
+
+ if (c->_c_waiters) c->_c_waiters--;
+ else a_dec(&m->_m_waiters);
+
+ a_store(&c->_c_lock, 0);
+ if (c->_c_lockwait) __wake(&c->_c_lock, 1, 1);
}
static void cleanup(void *p)
@@ -30,28 +35,35 @@ static void cleanup(void *p)
int pthread_cond_timedwait(pthread_cond_t *c, pthread_mutex_t *m, const struct timespec *ts)
{
struct cm cm = { .c=c, .m=m };
- int r, e, tid;
+ int r, e=0, seq;
if (ts && ts->tv_nsec >= 1000000000UL)
return EINVAL;
pthread_testcancel();
- if (c->_c_mutex != (void *)-1) c->_c_mutex = m;
+ if (c->_c_mutex == (void *)-1) {
+ a_inc(&c->_c_waiters);
+ } else {
+ c->_c_mutex = m;
+ while (a_swap(&c->_c_lock, 1))
+ __wait(&c->_c_lock, &c->_c_lockwait, 1, 1);
+ c->_c_waiters++;
+ a_store(&c->_c_lock, 0);
+ if (c->_c_lockwait) __wake(&c->_c_lock, 1, 1);
+ }
- a_inc(&c->_c_waiters);
- c->_c_block = tid = pthread_self()->tid;
+ seq = c->_c_seq;
if ((r=pthread_mutex_unlock(m))) return r;
- do e = __timedwait(&c->_c_block, tid, c->_c_clock, ts, cleanup, &cm, 0);
- while (c->_c_block == tid && (!e || e==EINTR));
+ do e = __timedwait(&c->_c_seq, seq, c->_c_clock, ts, cleanup, &cm, 0);
+ while (c->_c_seq == seq && (!e || e==EINTR));
if (e == EINTR) e = 0;
unwait(c, m);
if ((r=pthread_mutex_lock(m))) return r;
- pthread_testcancel();
return e;
}