[dm-devel] use regular gendisk registration in device mapper

[Mike Snitzer]

On Sun, Jul 25 2021 at  1:54P -0400,
Christoph Hellwig <hch at lst.de> 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.

s/not/now/

> This did not make a different to my testing
> using dmsetup and the lvm2 tools.

I'll try these changes running through the lvm2 testsuite.