On Thu, Jul 14, 2022 at 06:13:41AM -0700, Christoph Hellwig wrote: > On Thu, Jul 14, 2022 at 06:32:01PM +0800, Ming Lei wrote: > > However, ublk may not add disk in case of starting device failure, then > > del_gendisk() won't be called when removing ublk device, so blk_mq_exit_queue > > will not be callsed, and it can be bit hard to deal with this kind of > > merge conflict. > > So base it on a tree that has everything you need. > > > Turns out ublk's queue/disk use model is very similar with scsi, so switch > > to scsi's model by allocating disk and queue independently, then it can be > > quite easy to handle v5.20 merge conflict by replacing blk_cleanup_queue > > with blk_mq_destroy_queue. > > Don't do that. That thing really is a workaround for the lack of admin > queues in scsi. Nothing newly designed should use it. It will not > allow to optimize things and cause maintainaince burden down the road. The problem is that you moved part of blk_cleanup_queue() into del_gendisk(). Here, the issue Jens reproduced is that we don't add disk yet, so won't call del_gendisk(). The queue & disk is allocated & initialized correctly. Then how to do the part done by original blk_cleanup_queue() without calling blk_mq_destroy_queue()? Thanks, Ming
