Commit dc96cefe authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

blk-mq: fix stale tag depth for shared sched tags in blk_mq_update_nr_requests() 



Commit 7f2799c5 ("blk-mq: cleanup shared tags case in
blk_mq_update_nr_requests()") moves blk_mq_tag_update_sched_shared_tags()
before q->nr_requests is updated, however, it's still using the old
q->nr_requests to resize tag depth.

Fix this problem by passing in expected new tag depth.

Fixes: 7f2799c5 ("blk-mq: cleanup shared tags case in blk_mq_update_nr_requests()")
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarNilay Shroff <nilay@linux.ibm.com>
Reported-by: default avatarChris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-block/20251014130507.4187235-2-clm@meta.com/


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 455281c0

block/blk-mq-sched.c

+1 −1
Original line number Diff line number Diff line
@@ -557,7 +557,7 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e, 
	if (blk_mq_is_shared_tags(flags)) {

		/* Shared tags are stored at index 0 in @et->tags. */

		q->sched_shared_tags = et->tags[0];

		blk_mq_tag_update_sched_shared_tags(q);

		blk_mq_tag_update_sched_shared_tags(q, et->nr_requests);

	}



	queue_for_each_hw_ctx(q, hctx, i) {

block/blk-mq-tag.c

+3 −2
Original line number Diff line number Diff line
@@ -622,10 +622,11 @@ void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size 
	sbitmap_queue_resize(&tags->bitmap_tags, size - set->reserved_tags);

}



void blk_mq_tag_update_sched_shared_tags(struct request_queue *q)

void blk_mq_tag_update_sched_shared_tags(struct request_queue *q,

					 unsigned int nr)

{

	sbitmap_queue_resize(&q->sched_shared_tags->bitmap_tags,

			     q->nr_requests - q->tag_set->reserved_tags);

			     nr - q->tag_set->reserved_tags);

}



/**

block/blk-mq.c

+1 −1
Original line number Diff line number Diff line
@@ -4941,7 +4941,7 @@ struct elevator_tags *blk_mq_update_nr_requests(struct request_queue *q, 
		 * tags can't grow, see blk_mq_alloc_sched_tags().

		 */

		if (q->elevator)

			blk_mq_tag_update_sched_shared_tags(q);

			blk_mq_tag_update_sched_shared_tags(q, nr);

		else

			blk_mq_tag_resize_shared_tags(set, nr);

	} else if (!q->elevator) {

block/blk-mq.h

+2 −1
Original line number Diff line number Diff line
@@ -186,7 +186,8 @@ void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx, 
void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags);

void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set,

		unsigned int size);

void blk_mq_tag_update_sched_shared_tags(struct request_queue *q);

void blk_mq_tag_update_sched_shared_tags(struct request_queue *q,

					 unsigned int nr);



void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool);

void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn,