blk-mq: Add blk_mq_tag_update_sched_shared_sbitmap()

Put the functionality to update the sched shared sbitmap size in a common
function.

Since the same formula is always used to resize, and it can be got from
the request queue argument, so just pass the request queue pointer.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/1633429419-228500-10-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: John Garry

block/blk-mq-sched.c

@@ -575,8 +575,7 @@ static int blk_mq_init_sched_shared_sbitmap(struct request_queue *queue)
 					&queue->sched_breserved_tags;
 	}
 
-	sbitmap_queue_resize(&queue->sched_bitmap_tags,
-			     queue->nr_requests - set->reserved_tags);
+	blk_mq_tag_update_sched_shared_sbitmap(queue);
 
 	return 0;
 }

block/blk-mq-tag.c

@@ -634,6 +634,12 @@ void blk_mq_tag_resize_shared_sbitmap(struct blk_mq_tag_set *set, unsigned int s
 	sbitmap_queue_resize(&set->__bitmap_tags, size - set->reserved_tags);
 }
 
+void blk_mq_tag_update_sched_shared_sbitmap(struct request_queue *q)
+{
+	sbitmap_queue_resize(&q->sched_bitmap_tags,
+			     q->nr_requests - q->tag_set->reserved_tags);
+}
+
 /**
  * blk_mq_unique_tag() - return a tag that is unique queue-wide
  * @rq: request for which to compute a unique tag

block/blk-mq-tag.h

@@ -50,6 +50,7 @@ extern int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
 					unsigned int depth, bool can_grow);
 extern void blk_mq_tag_resize_shared_sbitmap(struct blk_mq_tag_set *set,
 					     unsigned int size);
+extern void blk_mq_tag_update_sched_shared_sbitmap(struct request_queue *q);
 
 extern void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool);
 void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,

block/blk-mq.c

@@ -3650,8 +3650,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
 		q->nr_requests = nr;
 		if (blk_mq_is_sbitmap_shared(set->flags)) {
 			if (q->elevator)
-				sbitmap_queue_resize(&q->sched_bitmap_tags,
-						     nr - set->reserved_tags);
+				blk_mq_tag_update_sched_shared_sbitmap(q);
 			else
 				blk_mq_tag_resize_shared_sbitmap(set, nr);
 		}