On 8/4/21 3:41 AM, Christoph Hellwig wrote:

Hi all,

The device mapper code currently has a somewhat odd gendisk registration
scheme where it calls add_disk early, but uses a special flag to skip the
"queue registration", which is a major part of add_disk.  This series
improves the block layer holder tracking to work on an entirely
unregistered disk and thus allows device mapper to use the normal scheme
of calling add_disk when it is ready to accept I/O.

Note that this leads to a user visible change - the sysfs attributes on
the disk and the dm directory hanging off it are not only visible once
the initial table is loaded.  This did not make a different to my testing
using dmsetup and the lvm2 tools.

Applied, thanks.

-- 
Jens Axboe