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Commit 3a5088c8 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: respect BLK_MQ_F_NO_SCHED 



If one driver claims that it doesn't support io scheduler via
BLK_MQ_F_NO_SCHED, we should not allow to change and show the
availabe io schedulers.

This patch adds check to enhance this behaviour.

Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 005882e5

block/elevator.c

+10 −2
Original line number Diff line number Diff line
@@ -1098,12 +1098,20 @@ int elevator_change(struct request_queue *q, const char *name) 
}

EXPORT_SYMBOL(elevator_change);



static inline bool elv_support_iosched(struct request_queue *q)

{

	if (q->mq_ops && q->tag_set && (q->tag_set->flags &

				BLK_MQ_F_NO_SCHED))

		return false;

	return true;

}



ssize_t elv_iosched_store(struct request_queue *q, const char *name,

			  size_t count)

{

	int ret;



	if (!(q->mq_ops || q->request_fn))

	if (!(q->mq_ops || q->request_fn) || !elv_support_iosched(q))

		return count;



	ret = __elevator_change(q, name);
@@ -1135,7 +1143,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name) 
			len += sprintf(name+len, "[%s] ", elv->elevator_name);

			continue;

		}

		if (__e->uses_mq && q->mq_ops)

		if (__e->uses_mq && q->mq_ops && elv_support_iosched(q))

			len += sprintf(name+len, "%s ", __e->elevator_name);

		else if (!__e->uses_mq && !q->mq_ops)

			len += sprintf(name+len, "%s ", __e->elevator_name);