pthread_barrier_wait: properly check the wait condition (#644)

- minor code-style fixes;

mac/hid.c

@@ -54,15 +54,15 @@ static int pthread_barrier_init(pthread_barrier_t *barrier, const pthread_barrie
 {
 	(void) attr;
 
-	if(count == 0) {
+	if (count == 0) {
 		errno = EINVAL;
 		return -1;
 	}
 
-	if(pthread_mutex_init(&barrier->mutex, 0) < 0) {
+	if (pthread_mutex_init(&barrier->mutex, 0) < 0) {
 		return -1;
 	}
-	if(pthread_cond_init(&barrier->cond, 0) < 0) {
+	if (pthread_cond_init(&barrier->cond, 0) < 0) {
 		pthread_mutex_destroy(&barrier->mutex);
 		return -1;
 	}
@@ -83,16 +83,18 @@ static int pthread_barrier_wait(pthread_barrier_t *barrier)
 {
 	pthread_mutex_lock(&barrier->mutex);
 	++(barrier->count);
-	if(barrier->count >= barrier->trip_count)
-	{
+	if (barrier->count >= barrier->trip_count) {
 		barrier->count = 0;
-		pthread_cond_broadcast(&barrier->cond);
 		pthread_mutex_unlock(&barrier->mutex);
+		pthread_cond_broadcast(&barrier->cond);
 		return 1;
 	}
-	else
-	{
-		pthread_cond_wait(&barrier->cond, &(barrier->mutex));
+	else {
+		do {
+			pthread_cond_wait(&barrier->cond, &(barrier->mutex));
+		}
+		while (barrier->count != 0);
+
 		pthread_mutex_unlock(&barrier->mutex);
 		return 0;
 	}