On 10/19/20 10:42 AM, Hui Su wrote:
> @@ -633,23 +633,21 @@ static struct elevator_type
> *elevator_get_default(struct request_queue *q)
> */
> static struct elevator_type *elevator_get_by_features(struct request_queue
> *q)
> {
> - struct elevator_type *e, *found = NULL;
> + struct elevator_type *e = NULL;
>
> spin_lock(&elv_list_lock);
> -
> list_for_each_entry(e, &elv_list, list) {
> if (elv_support_features(e->elevator_features,
> q->required_elevator_features)) {
> - found = e;
> break;
> }
> }
> + spin_unlock(&elv_list_lock);
>
> - if (found && !try_module_get(found->elevator_owner))
> - found = NULL;
> + if (e && !try_module_get(e->elevator_owner))
> + e = NULL;
>
> - spin_unlock(&elv_list_lock);
> - return found;
> + return e;
> }
This looks wrong as well. If we don't match the elevator, then we just
return the last one. Or maybe even a totally invalid entry, depending on
how the list iteration works.
--
Jens Axboe
