Add a pointer, to the containing device, within struct dm_zone and
kill dmz_zone_to_dev().
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>