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

Commit 7f2799c546db ("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: 7f2799c546db ("blk-mq: cleanup shared tags case in blk_mq_update_nr_requests()")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reported-by: Chris Mason <clm@meta.com>
Link: https://lore.kernel.org/linux-block/20251014130507.4187235-2-clm@meta.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index d06bb137a74377ad94ca711522a1afb441293d2d..e0bed16485c3464d60baa86143f42aa85224033d 100644 (file)
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -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) {

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index c7a4d4b9cc87b938315d40346daa46ad86d346c2..5b664dbdf655575d092dc0789be56f42ca3c8be5 100644 (file)
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -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);
 }
 
 /**

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 09f57941416159524eec14fdeed93f3132eb14b2..d626d32f6e576f95bc68495c467a9d9c7b73a581 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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) {

diff --git a/block/blk-mq.h b/block/blk-mq.h
index af42dc018808340ba3ae3168fc6f04de828820d0..c4fccdeb54412978665f54ca44d8456095335009 100644 (file)
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -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,