keep lock less long, we do not need it for the second if

src/drivers/driver_common/driver_common.c

@@ -172,6 +172,8 @@ struct starpu_task *_starpu_get_worker_task(struct _starpu_worker *args, int wor
 		return NULL;
 	}
 
+	_STARPU_PTHREAD_MUTEX_UNLOCK(args->sched_mutex);
+
 	if (_starpu_worker_get_status(workerid) == STATUS_SLEEPING)
 	{
 		_STARPU_TRACE_WORKER_SLEEP_END
@@ -179,7 +181,5 @@ struct starpu_task *_starpu_get_worker_task(struct _starpu_worker *args, int wor
 		_starpu_worker_set_status(workerid, STATUS_UNKNOWN);
 	}
 
-	_STARPU_PTHREAD_MUTEX_UNLOCK(args->sched_mutex);
-
 	return task;
 }