On Mon, Jan 22, 2018 at 11:35:48AM +0800, Ming Lei wrote:

Except for DM_MAPIO_REQUEUE, map_request() handles other dispatch exception
already, so return BLK_STS_* from map_request() directly.

Another change is that if dm_dispatch_clone_request() returns
BLK_STS_DEV_RESOURCE from underlying queue, this status is returned
to blk-mq too, since underlying queue's RESTART can handle dm-rq's
RESTART in this case.

Hammm, this is obvious wrong, :-(

-- 
Ming