nvme: split command copy into a helper

We'll need it for batched submit as well. Since we now have a copy
helper, get rid of the nvme_submit_cmd() wrapper.
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/pci.c

@@ -500,22 +500,13 @@ static inline void nvme_write_sq_db(struct nvme_queue *nvmeq, bool write_sq)
 	nvmeq->last_sq_tail = nvmeq->sq_tail;
 }
 
-/**
- * nvme_submit_cmd() - Copy a command into a queue and ring the doorbell
- * @nvmeq: The queue to use
- * @cmd: The command to send
- * @write_sq: whether to write to the SQ doorbell
- */
-static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd,
-			    bool write_sq)
+static inline void nvme_sq_copy_cmd(struct nvme_queue *nvmeq,
+				    struct nvme_command *cmd)
 {
-	spin_lock(&nvmeq->sq_lock);
 	memcpy(nvmeq->sq_cmds + (nvmeq->sq_tail << nvmeq->sqes),
-	       cmd, sizeof(*cmd));
+		absolute_pointer(cmd), sizeof(*cmd));
 	if (++nvmeq->sq_tail == nvmeq->q_depth)
 		nvmeq->sq_tail = 0;
-	nvme_write_sq_db(nvmeq, write_sq);
-	spin_unlock(&nvmeq->sq_lock);
 }
 
 static void nvme_commit_rqs(struct blk_mq_hw_ctx *hctx)
@@ -957,7 +948,10 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 	}
 
 	blk_mq_start_request(req);
-	nvme_submit_cmd(nvmeq, cmnd, bd->last);
+	spin_lock(&nvmeq->sq_lock);
+	nvme_sq_copy_cmd(nvmeq, &iod->cmd);
+	nvme_write_sq_db(nvmeq, bd->last);
+	spin_unlock(&nvmeq->sq_lock);
 	return BLK_STS_OK;
 out_unmap_data:
 	nvme_unmap_data(dev, req);
@@ -1140,7 +1134,11 @@ static void nvme_pci_submit_async_event(struct nvme_ctrl *ctrl)
 
 	c.common.opcode = nvme_admin_async_event;
 	c.common.command_id = NVME_AQ_BLK_MQ_DEPTH;
-	nvme_submit_cmd(nvmeq, &c, true);
+
+	spin_lock(&nvmeq->sq_lock);
+	nvme_sq_copy_cmd(nvmeq, &c);
+	nvme_write_sq_db(nvmeq, true);
+	spin_unlock(&nvmeq->sq_lock);
 }
 
 static int adapter_delete_queue(struct nvme_dev *dev, u8 opcode, u16 id)