On Tue, 2017-04-18 at 08:52 -0700, Christoph Hellwig wrote: > Now that we always have a ->complete callback we can remove the direct > call to blk_mq_end_request, as well as the error argument to > blk_mq_complete_request. Hello Christoph, Please add a runtime check that issues a warning early if a .complete callback function is missing. Are you sure that all blk-mq drivers have a .complete callback? In the request-errors branch of your block git tree I found the following: static const struct blk_mq_ops rbd_mq_ops = { .queue_rq = rbd_queue_rq, .init_request = rbd_init_request, }; static const struct blk_mq_ops ubiblock_mq_ops = { .queue_rq = ubiblock_queue_rq, .init_request = ubiblock_init_request, }; Thanks, Bart.