Re: [PATCHv2] block: fix leaking minors of hidden disks

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Fri, Oct 07, 2022 at 12:38:25PM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch@xxxxxxxxxx>
> 
> The major/minor of a hidden gendisk is not propagated to the block
> device. This is required to suppress it from being visible. For these
> disks, we need to handle freeing the dynamic minor directly when it's
> released since bdev_free_inode() won't be able to.

This now leads to a different lifetime.  I think the proper fix is
the one below (untested):

diff --git a/block/genhd.c b/block/genhd.c
index d36fabf0abc1f..1752ce356484e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -507,6 +507,8 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 		 */
 		dev_set_uevent_suppress(ddev, 0);
 		disk_uevent(disk, KOBJ_ADD);
+	} else {
+		disk->part0->bd_dev = ddev->devt;
 	}
 
 	disk_update_readahead(disk);