blk-mq: update driver tags request table when start request

Now we update driver tags request table in blk_mq_get_driver_tag(),
so the driver that support queue_rqs() have to update that inflight
table by itself.

Move it to blk_mq_start_request(), which is a better place where
we setup the deadline for request timeout check. And it's just
where the request becomes inflight.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230913151616.3164338-5-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -1259,6 +1259,7 @@ void blk_mq_start_request(struct request *rq)
 
 	blk_add_timer(rq);
 	WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
+	rq->mq_hctx->tags->rqs[rq->tag] = rq;
 
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 	if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)

block/blk-mq.h

@@ -351,12 +351,9 @@ bool __blk_mq_alloc_driver_tag(struct request *rq);
 
 static inline bool blk_mq_get_driver_tag(struct request *rq)
 {
-	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
-
 	if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_alloc_driver_tag(rq))
 		return false;
 
-	hctx->tags->rqs[rq->tag] = rq;
 	return true;
 }
 

drivers/block/virtio_blk.c

@@ -470,8 +470,6 @@ static bool virtblk_prep_rq_batch(struct request *req)
 	struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
 	struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
 
-	req->mq_hctx->tags->rqs[req->tag] = req;
-
 	return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK;
 }
 

drivers/nvme/host/pci.c

@@ -924,7 +924,6 @@ static bool nvme_prep_rq_batch(struct nvme_queue *nvmeq, struct request *req)
 	if (unlikely(!nvme_check_ready(&nvmeq->dev->ctrl, req, true)))
 		return false;
 
-	req->mq_hctx->tags->rqs[req->tag] = req;
 	return nvme_prep_rq(nvmeq->dev, req) == BLK_STS_OK;
 }