On Tue, Dec 26, 2017 at 10:22:53PM -0500, Mike Snitzer wrote: > All requests allocated from a request_queue with this callback set can > failover their requests during completion. > > This callback is expected to use the blk_steal_bios() interface to > transfer a request's bios back to an upper-layer bio-based > request_queue. > > This will be used by both NVMe multipath and DM multipath. Without it > DM multipath cannot get access to NVMe-specific error handling that NVMe > core provides in nvme_complete_rq(). And the whole point is that it should not get any such access. The reason why we did nvme multipathing differently is because the design of dm-multipath inflicts so much pain on users that we absolutely want to avoid it this time around.
