nvme: introduce nvme_start_request

In preparation for nvme-multipath IO stats accounting, we want the
accounting to happen in a centralized place. The request completion
is already centralized, but we need a common helper to request I/O
start.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>

drivers/nvme/host/apple.c

@@ -763,7 +763,7 @@ static blk_status_t apple_nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 			goto out_free_cmd;
 	}
 
-	blk_mq_start_request(req);
+	nvme_start_request(req);
 	apple_nvme_submit_cmd(q, cmnd);
 	return BLK_STS_OK;
 

drivers/nvme/host/fc.c

@@ -2733,7 +2733,7 @@ nvme_fc_start_fcp_op(struct nvme_fc_ctrl *ctrl, struct nvme_fc_queue *queue,
 	atomic_set(&op->state, FCPOP_STATE_ACTIVE);
 
 	if (!(op->flags & FCOP_FLAGS_AEN))
-		blk_mq_start_request(op->rq);
+		nvme_start_request(op->rq);
 
 	cmdiu->csn = cpu_to_be32(atomic_inc_return(&queue->csn));
 	ret = ctrl->lport->ops->fcp_io(&ctrl->lport->localport,

drivers/nvme/host/nvme.h

@@ -1012,6 +1012,11 @@ static inline void nvme_hwmon_exit(struct nvme_ctrl *ctrl)
 }
 #endif
 
+static inline void nvme_start_request(struct request *rq)
+{
+	blk_mq_start_request(rq);
+}
+
 static inline bool nvme_ctrl_sgl_supported(struct nvme_ctrl *ctrl)
 {
 	return ctrl->sgls & ((1 << 0) | (1 << 1));

drivers/nvme/host/pci.c

@@ -907,7 +907,7 @@ static blk_status_t nvme_prep_rq(struct nvme_dev *dev, struct request *req)
 			goto out_unmap_data;
 	}
 
-	blk_mq_start_request(req);
+	nvme_start_request(req);
 	return BLK_STS_OK;
 out_unmap_data:
 	nvme_unmap_data(dev, req);

drivers/nvme/host/rdma.c

@@ -2040,7 +2040,7 @@ static blk_status_t nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
 	if (ret)
 		goto unmap_qe;
 
-	blk_mq_start_request(rq);
+	nvme_start_request(rq);
 
 	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
 	    queue->pi_support &&

drivers/nvme/host/tcp.c

@@ -2405,7 +2405,7 @@ static blk_status_t nvme_tcp_queue_rq(struct blk_mq_hw_ctx *hctx,
 	if (unlikely(ret))
 		return ret;
 
-	blk_mq_start_request(rq);
+	nvme_start_request(rq);
 
 	nvme_tcp_queue_request(req, true, bd->last);
 

drivers/nvme/target/loop.c

@@ -145,7 +145,7 @@ static blk_status_t nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 	if (ret)
 		return ret;
 
-	blk_mq_start_request(req);
+	nvme_start_request(req);
 	iod->cmd.common.flags |= NVME_CMD_SGL_METABUF;
 	iod->req.port = queue->ctrl->port;
 	if (!nvmet_req_init(&iod->req, &queue->nvme_cq,