null_blk: complete requests from ->timeout

By completing the request entirely in the driver we can remove the
BLK_EH_HANDLED return value and thus the split responsibility between the
driver and the block layer that has been causing trouble.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/null_blk.c

@@ -1365,7 +1365,8 @@ static blk_qc_t null_queue_bio(struct request_queue *q, struct bio *bio)
 static enum blk_eh_timer_return null_rq_timed_out_fn(struct request *rq)
 {
 	pr_info("null: rq %p timed out\n", rq);
-	return BLK_EH_HANDLED;
+	blk_mq_complete_request(rq);
+	return BLK_EH_DONE;
 }
 
 static int null_rq_prep_fn(struct request_queue *q, struct request *req)
@@ -1427,7 +1428,8 @@ static void null_request_fn(struct request_queue *q)
 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
 {
 	pr_info("null: rq %p timed out\n", rq);
-	return BLK_EH_HANDLED;
+	blk_mq_complete_request(rq);
+	return BLK_EH_DONE;
 }
 
 static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,