block: simplify disk shutdown

Set the queue dying flag and call blk_mq_exit_queue from del_gendisk for
all disks that do not have separately allocated queues, and thus remove
the need to call blk_cleanup_queue for them.

Rename blk_cleanup_disk to blk_mq_destroy_queue to make it clear that
this function is intended only for separately allocated blk-mq queues.

This saves an extra queue freeze for devices without a separately
allocated queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20220619060552.1850436-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 13 insertions, 10 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 278227ba1d53..4d15f828c449 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -617,6 +617,8 @@ void del_gendisk(struct gendisk *disk)
 	 * Fail any new I/O.
 	 */
 	set_bit(GD_DEAD, &disk->state);
+	if (test_bit(GD_OWNS_QUEUE, &disk->state))
+		blk_queue_flag_set(QUEUE_FLAG_DYING, q);
 	set_capacity(disk, 0);
 
 	/*
@@ -663,11 +665,16 @@ void del_gendisk(struct gendisk *disk)
 	blk_mq_unquiesce_queue(q);
 
 	/*
-	 * Allow using passthrough request again after the queue is torn down.
+	 * If the disk does not own the queue, allow using passthrough requests
+	 * again.  Else leave the queue frozen to fail all I/O.
 	 */
-	blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
-	__blk_mq_unfreeze_queue(q, true);
-
+	if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
+		blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
+		__blk_mq_unfreeze_queue(q, true);
+	} else {
+		if (queue_is_mq(q))
+			blk_mq_exit_queue(q);
+	}
 }
 EXPORT_SYMBOL(del_gendisk);
 
@@ -1338,9 +1345,6 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 {
 	struct gendisk *disk;
 
-	if (!blk_get_queue(q))
-		return NULL;
-
 	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 	if (!disk)
 		goto out_put_queue;
@@ -1391,7 +1395,6 @@ out_put_queue:
 	blk_put_queue(q);
 	return NULL;
 }
-EXPORT_SYMBOL(__alloc_disk_node);
 
 struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
 {
@@ -1404,9 +1407,10 @@ struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
 
 	disk = __alloc_disk_node(q, node, lkclass);
 	if (!disk) {
-		blk_cleanup_queue(q);
+		blk_put_queue(q);
 		return NULL;
 	}
+	set_bit(GD_OWNS_QUEUE, &disk->state);
 	return disk;
 }
 EXPORT_SYMBOL(__blk_alloc_disk);
@@ -1439,7 +1443,6 @@ EXPORT_SYMBOL(put_disk);
  */
 void blk_cleanup_disk(struct gendisk *disk)
 {
-	blk_cleanup_queue(disk->queue);
 	put_disk(disk);
 }
 EXPORT_SYMBOL(blk_cleanup_disk);