Revert "blk-cgroup: delay blk-cgroup initialization until add_disk"

This reverts commit 178fa7d4.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -466,13 +466,9 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 	 */
 	pm_runtime_set_memalloc_noio(ddev, true);
 
-	ret = blkcg_init_disk(disk);
-	if (ret)
-		goto out_del_block_link;
-
 	ret = blk_integrity_add(disk);
 	if (ret)
-		goto out_blkcg_exit;
+		goto out_del_block_link;
 
 	disk->part0->bd_holder_dir =
 		kobject_create_and_add("holders", &ddev->kobj);
@@ -538,8 +534,6 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 	kobject_put(disk->part0->bd_holder_dir);
 out_del_integrity:
 	blk_integrity_del(disk);
-out_blkcg_exit:
-	blkcg_exit_disk(disk);
 out_del_block_link:
 	if (!sysfs_deprecated)
 		sysfs_remove_link(block_depr, dev_name(ddev));
@@ -668,8 +662,6 @@ void del_gendisk(struct gendisk *disk)
 	rq_qos_exit(q);
 	blk_mq_unquiesce_queue(q);
 
-	blkcg_exit_disk(disk);
-
 	/*
 	 * If the disk does not own the queue, allow using passthrough requests
 	 * again.  Else leave the queue frozen to fail all I/O.
@@ -1178,6 +1170,8 @@ static void disk_release(struct device *dev)
 	    !test_bit(GD_ADDED, &disk->state))
 		blk_mq_exit_queue(disk->queue);
 
+	blkcg_exit_disk(disk);
+
 	bioset_exit(&disk->bio_split);
 
 	disk_release_events(disk);
@@ -1390,6 +1384,9 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 	if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
 		goto out_destroy_part_tbl;
 
+	if (blkcg_init_disk(disk))
+		goto out_erase_part0;
+
 	rand_initialize_disk(disk);
 	disk_to_dev(disk)->class = &block_class;
 	disk_to_dev(disk)->type = &disk_type;
@@ -1402,6 +1399,8 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 #endif
 	return disk;
 
+out_erase_part0:
+	xa_erase(&disk->part_tbl, 0);
 out_destroy_part_tbl:
 	xa_destroy(&disk->part_tbl);
 	disk->part0->bd_disk = NULL;