diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c index 3b52cd0c2d..663b6f99b5 100644 --- a/nptl/pthread_cond_wait.c +++ b/nptl/pthread_cond_wait.c @@ -382,17 +382,15 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex, return err; } - /* Now wait until a signal is available in our group or it is closed. - Acquire MO so that if we observe (signals == lowseq) after group - switching in __condvar_quiesce_and_switch_g1, we synchronize with that - store and will see the prior update of __g1_start done while switching - groups too. */ - unsigned int signals = atomic_load_acquire (cond->__data.__g_signals + g); - do - { while (1) { + /* Now wait until a signal is available in our group or it is closed. + Acquire MO so that if we observe (signals == lowseq) after group + switching in __condvar_quiesce_and_switch_g1, we synchronize with that + store and will see the prior update of __g1_start done while switching + groups too. */ + unsigned int signals = atomic_load_acquire (cond->__data.__g_signals + g); uint64_t g1_start = __condvar_load_g1_start_relaxed (cond); unsigned int lowseq = (g1_start & 1) == g ? signals : g1_start & ~1U; @@ -401,7 +399,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex, /* If the group is closed already, then this waiter originally had enough extra signals to consume, up until the time its group was closed. */ - goto done; + break; } /* If there is an available signal, don't block. @@ -410,7 +408,16 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex, G2, but in either case we're allowed to consume the available signal and should not block anymore. */ if ((int)(signals - lowseq) >= 2) - break; + { + /* Try to grab a signal. See above for MO. (if we do another loop + iteration we need to see the correct value of g1_start) */ + if (atomic_compare_exchange_weak_acquire ( + cond->__data.__g_signals + g, + &signals, signals - 2)) + break; + else + continue; + } // Now block. struct _pthread_cleanup_buffer buffer; @@ -431,19 +438,9 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex, /* If we timed out, we effectively cancel waiting. */ __condvar_cancel_waiting (cond, seq, g, private); result = err; - goto done; + break; } - - /* Reload signals. See above for MO. */ - signals = atomic_load_acquire (cond->__data.__g_signals + g); } - } - /* Try to grab a signal. See above for MO. (if we do another loop - iteration we need to see the correct value of g1_start) */ - while (!atomic_compare_exchange_weak_acquire (cond->__data.__g_signals + g, - &signals, signals - 2)); - - done: /* Confirm that we have been woken. We do that before acquiring the mutex to allow for execution of pthread_cond_destroy while having acquired the