diff options
Diffstat (limited to 'nuttx/sched/pthread_completejoin.c')
-rw-r--r-- | nuttx/sched/pthread_completejoin.c | 100 |
1 files changed, 59 insertions, 41 deletions
diff --git a/nuttx/sched/pthread_completejoin.c b/nuttx/sched/pthread_completejoin.c index 571bb6862..76b2e9f80 100644 --- a/nuttx/sched/pthread_completejoin.c +++ b/nuttx/sched/pthread_completejoin.c @@ -65,16 +65,16 @@ ************************************************************/ /************************************************************ - * Function: pthread_destroyjoininfo + * Function: pthread_notifywaiters * * Description: - * Destroy a join_t structure. This must - * be done by the child thread at child thread destruction - * time. + * Notify all other threads waiting in phread join for this + * thread's exit data. This must be done by the child + * at child thread destruction time. * ************************************************************/ -static void pthread_destroyjoininfo(FAR join_t *pjoin) +static boolean pthread_notifywaiters(FAR join_t *pjoin) { int ntasks_waiting; int status; @@ -111,14 +111,9 @@ static void pthread_destroyjoininfo(FAR join_t *pjoin) */ (void)pthread_takesemaphore(&pjoin->data_sem); - (void)sem_destroy(&pjoin->data_sem); + return TRUE; } - - /* All of the joined threads have had received the exit value. - * Now we can destroy this thread's exit semaphore - */ - - (void)sem_destroy(&pjoin->exit_sem); + return FALSE; } /************************************************************ @@ -148,7 +143,6 @@ static void pthread_destroyjoininfo(FAR join_t *pjoin) int pthread_completejoin(pid_t pid, FAR void *exit_value) { FAR join_t *pjoin; - boolean detached = FALSE; dbg("process_id=%d exit_value=%p\n", pid, exit_value); @@ -164,48 +158,72 @@ int pthread_completejoin(pid_t pid, FAR void *exit_value) } else { - /* Has the thread been marked as detached? */ + boolean waiters; + + /* Save the return exit value in the thread structure. */ pjoin->terminated = TRUE; - detached = pjoin->detached; - if (detached) - { - dbg("Detaching\n"); + pjoin->exit_value = exit_value; - /* If so, then remove the thread's structure from the private - * data set. After this point, no other thread can perform a join - * operation. - */ + /* Notify waiters of the availability of the exit value */ - (void)pthread_removejoininfo(pid); - (void)pthread_givesemaphore(&g_join_semaphore); + waiters = pthread_notifywaiters(pjoin); - /* Destroy this thread data structure. */ + /* If there are no waiters and if the thread is marked as detached. + * then discard the join information now. Otherwise, the pthread + * join logic will call pthread_destroyjoin() when all of the threads + * have sampled the exit value. + */ - pthread_destroyjoininfo(pjoin); + if (!waiters && pjoin->detached) + { + pthread_destroyjoin(pjoin); + } - /* Deallocate the join entry if it was detached. */ + /* Giving the following semaphore will allow the waiters + * to call pthread_destroyjoin. + */ - sched_free((FAR void*)pjoin); - } + (void)pthread_givesemaphore(&g_join_semaphore); + } - /* No, then we can assume that some other thread is waiting for the join info */ + return OK; +} - else - { - /* Save the return exit value in the thread structure. */ +/************************************************************ + * Function: pthread_destroyjoin + * + * Description: + * This is called from pthread_completejoin if the join + * info was detached or from pthread_join when the last + * waiting thread has received the thread exit info. + * + * Or it may never be called if the join info was never + * detached or if no thread ever calls pthread_join. In + * case, there is a memory leak! + * + * Assumptions: + * The caller holds g_join_semaphore + * + ************************************************************/ + +void pthread_destroyjoin(FAR join_t *pjoin) +{ + int status; - pjoin->exit_value = exit_value; + dbg("pjoin=0x%p\n", pjoin); - /* Destroy this thread data structure. */ + /* Remove the join info from the set of joins */ - pthread_destroyjoininfo(pjoin); + (void)pthread_removejoininfo((pid_t)pjoin->thread); - /* pthread_join may now access the thread entry structure. */ + /* Destroy its semaphores */ - (void)pthread_givesemaphore(&g_join_semaphore); - } - } + (void)sem_destroy(&pjoin->data_sem); + (void)sem_destroy(&pjoin->exit_sem); - return OK; + /* And deallocate the pjoin structure */ + + sched_free(pjoin); } + |