On Fri, Jul 14 2017 at 3:12am -0400, Christoph Hellwig <hch@xxxxxx> wrote: > Btw, we might want to expedite this to 4.13, a 4.13 now defaults > to blk-mq for scsi, and this patch would make sure that dm keeps > on just working with that switch. Don't think we need to rush anything in response to that change in SCSI's default. old .request_fn DM multipath works happily ontop of blk-mq devices (so long as all paths are blk-mq). Similarly, blk-mq DM multipath works ontop of all blk-mq devices. Lastly, old .request_fn DM multipath ontop of old .request_fn paths works fine. It is just blk-mq DM multipath ontop of old .request_fn paths that is disallowed in current upstream code. But again, I really don't see why we should even want/need to support that mode... hence my question raised in this RFC.
