On Wed, Oct 25, 2017 at 12:04:46PM -0600, Jens Axboe wrote:
> Since we now lookup elevator types with the appropriate multiqueue
> capability, allow schedulers to register with an alias alongside
> the real name. This is in preparation for allowing 'mq-deadline'
> to register an alias of 'deadline' as well.
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> block/elevator.c | 22 ++++++++++++++++------
> include/linux/elevator.h | 1 +
> 2 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/block/elevator.c b/block/elevator.c
> index b70e69f795db..dc0432e12ecf 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -83,6 +83,16 @@ bool elv_bio_merge_ok(struct request *rq, struct bio *bio)
> }
> EXPORT_SYMBOL(elv_bio_merge_ok);
>
> +static bool elevator_match(const struct elevator_type *e, const char *name)
> +{
> + if (!strcmp(e->elevator_name, name))
> + return true;
> + if (e->elevator_alias && !strcmp(e->elevator_alias, name))
> + return true;
> +
> + return false;
> +}
> +
> /*
> * Return scheduler with name 'name' and with matching 'mq capability
> */
> @@ -91,7 +101,7 @@ static struct elevator_type *elevator_find(const char *name, bool mq)
> struct elevator_type *e;
>
> list_for_each_entry(e, &elv_list, list) {
> - if (!strcmp(e->elevator_name, name) && !(mq ^ e->uses_mq))
> + if (elevator_match(e, name) && !(mq ^ e->uses_mq))
> return e;
> }
>
> @@ -922,9 +932,9 @@ int elv_register(struct elevator_type *e)
> spin_unlock(&elv_list_lock);
>
> /* print pretty message */
> - if (!strcmp(e->elevator_name, chosen_elevator) ||
> + if (elevator_match(e, chosen_elevator) ||
> (!*chosen_elevator &&
> - !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED)))
> + elevator_match(e, CONFIG_DEFAULT_IOSCHED)))
> def = " (default)";
>
> printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
> @@ -1077,8 +1087,7 @@ static int __elevator_change(struct request_queue *q, const char *name)
> if (!e)
> return -EINVAL;
>
> - if (q->elevator &&
> - !strcmp(elevator_name, q->elevator->type->elevator_name)) {
> + if (q->elevator && elevator_match(q->elevator->type, elevator_name)) {
> elevator_put(e);
> return 0;
> }
> @@ -1126,7 +1135,8 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
>
> spin_lock(&elv_list_lock);
> list_for_each_entry(__e, &elv_list, list) {
> - if (elv && !strcmp(elv->elevator_name, __e->elevator_name)) {
> + if (elv && elevator_match(elv, __e->elevator_name) &&
> + !(__e->uses_mq ^ (q->mq_ops != NULL))) {
Same thing here, (__e->uses_mq == (q->mq_ops != NULL)). Still confusing
but less so.
Otherwise Reviewed-by: Omar Sandoval <osandov@xxxxxx>
