[PATCH] block: fix leaking minors of hidden disks

Christoph Hellwig
2022-10-10T13:19:04Z

The major/minor of a hidden gendisk is not propagated to the block
device because it is never registered using bdev_add. But the lack of
bd_dev also causes the dynamic major minor number not to be freed.
Assign bd_dev manually to ensure the dynamic major minor gets freed.

Based on a patch by Keith Busch.

Fixes: 8ddcd653257c ("block: introduce GENHD_FL_HIDDEN")
Reported-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Daniel Wagner <dwagner@suse.de>
---
block/genhd.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index 514395361d7c5..17b33c62423df 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -507,6 +507,13 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
*/
dev_set_uevent_suppress(ddev, 0);
disk_uevent(disk, KOBJ_ADD);
+ } else {
+ /*
+ * Even if the block_device for a hidden gendisk is not
+ * registered, it needs to have a valid bd_dev so that the
+ * freeing of the dynamic major works.
+ */
+ disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
}

disk_update_readahead(disk);
--
2.30.2