On Thu, Jul 21, 2022 at 07:16:32AM +0200, Christoph Hellwig wrote: > Defer allocating the gendisk and request_queue until UBLK_CMD_START_DEV > is called. This avoids funky life times where a disk is allocated > and then can be added and removed multiple times, which has never been > supported by the block layer. As commented in last patch, tagset can be allocated once for retrieving affinity reliably from tagset's map instead of building it via blk_mq_map_queues() before allocating tagset, meantime the code gets simplified. Then you can still allocate queue/disk together. Thanks, Ming