nvme-pci: split metadata handling from nvme_map_data / nvme_unmap_data

This prepares for some bigger changes to the data mapping helpers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

drivers/nvme/host/pci.c

@@ -592,11 +592,6 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
 	dma_addr_t dma_addr = iod->first_dma, next_dma_addr;
 	int i;
 
-	if (blk_integrity_rq(req)) {
-		dma_unmap_page(dev->dev, iod->meta_dma,
-				rq_integrity_vec(req)->bv_len, dma_dir);
-	}
-
 	if (iod->nents) {
 		/* P2PDMA requests do not need to be unmapped */
 		if (!is_pci_p2pdma_page(sg_page(iod->sg)))
@@ -858,24 +853,23 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 		ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw, nr_mapped);
 	else
 		ret = nvme_pci_setup_prps(dev, req, &cmnd->rw);
-
+out:
 	if (ret != BLK_STS_OK)
-		goto out;
+		nvme_unmap_data(dev, req);
+	return ret;
+}
+
+static blk_status_t nvme_map_metadata(struct nvme_dev *dev, struct request *req,
+		struct nvme_command *cmnd)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 
-	ret = BLK_STS_IOERR;
-	if (blk_integrity_rq(req)) {
 	iod->meta_dma = dma_map_bvec(dev->dev, rq_integrity_vec(req),
-				dma_dir, 0);
+			rq_dma_dir(req), 0);
 	if (dma_mapping_error(dev->dev, iod->meta_dma))
-			goto out;
+		return BLK_STS_IOERR;
 	cmnd->rw.metadata = cpu_to_le64(iod->meta_dma);
-	}
-
-	return BLK_STS_OK;
-
-out:
-	nvme_unmap_data(dev, req);
-	return ret;
+	return 0;
 }
 
 /*
@@ -913,9 +907,17 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 			goto out_free_cmd;
 	}
 
+	if (blk_integrity_rq(req)) {
+		ret = nvme_map_metadata(dev, req, &cmnd);
+		if (ret)
+			goto out_unmap_data;
+	}
+
 	blk_mq_start_request(req);
 	nvme_submit_cmd(nvmeq, &cmnd, bd->last);
 	return BLK_STS_OK;
+out_unmap_data:
+	nvme_unmap_data(dev, req);
 out_free_cmd:
 	nvme_cleanup_cmd(req);
 	return ret;
@@ -924,10 +926,14 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
 static void nvme_pci_complete_rq(struct request *req)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	struct nvme_dev *dev = iod->nvmeq->dev;
 
 	nvme_cleanup_cmd(req);
+	if (blk_integrity_rq(req))
+		dma_unmap_page(dev->dev, iod->meta_dma,
+			       rq_integrity_vec(req)->bv_len, rq_data_dir(req));
 	if (blk_rq_nr_phys_segments(req))
-		nvme_unmap_data(iod->nvmeq->dev, req);
+		nvme_unmap_data(dev, req);
 	nvme_complete_rq(req);
 }