[PATCH 1/1] nvme-rdma: add helpers for mapping/unmapping request

[Max Gurtovoy]

Introduce nvme_rdma_dma_map_req/nvme_rdma_dma_unmap_req helper functions
to improve code readability and ease on the error flow.

Reviewed-by: Israel Rukshin <israelr at nvidia.com>
Signed-off-by: Max Gurtovoy <mgurtovoy at nvidia.com>
---
 drivers/nvme/host/rdma.c | 148 ++++++++++++++++++++++-----------------
 1 file changed, 84 insertions(+), 64 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 9c55e4be8a39..993e3a076a41 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1283,37 +1283,6 @@ static int nvme_rdma_inv_rkey(struct nvme_rdma_queue *queue,
 	return ib_post_send(queue->qp, &wr, NULL);
 }
 
-static void nvme_rdma_unmap_data(struct nvme_rdma_queue *queue,
-		struct request *rq)
-{
-	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
-	struct nvme_rdma_device *dev = queue->device;
-	struct ib_device *ibdev = dev->dev;
-	struct list_head *pool = &queue->qp->rdma_mrs;
-
-	if (!blk_rq_nr_phys_segments(rq))
-		return;
-
-	if (blk_integrity_rq(rq)) {
-		ib_dma_unmap_sg(ibdev, req->metadata_sgl->sg_table.sgl,
-				req->metadata_sgl->nents, rq_dma_dir(rq));
-		sg_free_table_chained(&req->metadata_sgl->sg_table,
-				      NVME_INLINE_METADATA_SG_CNT);
-	}
-
-	if (req->use_sig_mr)
-		pool = &queue->qp->sig_mrs;
-
-	if (req->mr) {
-		ib_mr_pool_put(queue->qp, pool, req->mr);
-		req->mr = NULL;
-	}
-
-	ib_dma_unmap_sg(ibdev, req->data_sgl.sg_table.sgl, req->data_sgl.nents,
-			rq_dma_dir(rq));
-	sg_free_table_chained(&req->data_sgl.sg_table, NVME_INLINE_SG_CNT);
-}
-
 static int nvme_rdma_set_sg_null(struct nvme_command *c)
 {
 	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
@@ -1522,22 +1491,27 @@ static int nvme_rdma_map_sg_pi(struct nvme_rdma_queue *queue,
 	return -EINVAL;
 }
 
-static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
-		struct request *rq, struct nvme_command *c)
+static void nvme_rdma_dma_unmap_req(struct ib_device *ibdev, struct request *rq)
 {
 	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
-	struct nvme_rdma_device *dev = queue->device;
-	struct ib_device *ibdev = dev->dev;
-	int pi_count = 0;
-	int count, ret;
 
-	req->num_sge = 1;
-	refcount_set(&req->ref, 2); /* send and recv completions */
+	if (blk_integrity_rq(rq)) {
+		ib_dma_unmap_sg(ibdev, req->metadata_sgl->sg_table.sgl,
+				req->metadata_sgl->nents, rq_dma_dir(rq));
+		sg_free_table_chained(&req->metadata_sgl->sg_table,
+				      NVME_INLINE_METADATA_SG_CNT);
+	}
 
-	c->common.flags |= NVME_CMD_SGL_METABUF;
+	ib_dma_unmap_sg(ibdev, req->data_sgl.sg_table.sgl, req->data_sgl.nents,
+			rq_dma_dir(rq));
+	sg_free_table_chained(&req->data_sgl.sg_table, NVME_INLINE_SG_CNT);
+}
 
-	if (!blk_rq_nr_phys_segments(rq))
-		return nvme_rdma_set_sg_null(c);
+static int nvme_rdma_dma_map_req(struct ib_device *ibdev, struct request *rq,
+		int *count, int *pi_count)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	int ret;
 
 	req->data_sgl.sg_table.sgl = (struct scatterlist *)(req + 1);
 	ret = sg_alloc_table_chained(&req->data_sgl.sg_table,
@@ -1549,9 +1523,9 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
 	req->data_sgl.nents = blk_rq_map_sg(rq->q, rq,
 					    req->data_sgl.sg_table.sgl);
 
-	count = ib_dma_map_sg(ibdev, req->data_sgl.sg_table.sgl,
-			      req->data_sgl.nents, rq_dma_dir(rq));
-	if (unlikely(count <= 0)) {
+	*count = ib_dma_map_sg(ibdev, req->data_sgl.sg_table.sgl,
+			       req->data_sgl.nents, rq_dma_dir(rq));
+	if (unlikely(*count <= 0)) {
 		ret = -EIO;
 		goto out_free_table;
 	}
@@ -1570,16 +1544,73 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
 
 		req->metadata_sgl->nents = blk_rq_map_integrity_sg(rq->q,
 				rq->bio, req->metadata_sgl->sg_table.sgl);
-		pi_count = ib_dma_map_sg(ibdev,
-					 req->metadata_sgl->sg_table.sgl,
-					 req->metadata_sgl->nents,
-					 rq_dma_dir(rq));
-		if (unlikely(pi_count <= 0)) {
+		*pi_count = ib_dma_map_sg(ibdev,
+					  req->metadata_sgl->sg_table.sgl,
+					  req->metadata_sgl->nents,
+					  rq_dma_dir(rq));
+		if (unlikely(*pi_count <= 0)) {
 			ret = -EIO;
 			goto out_free_pi_table;
 		}
 	}
 
+	return 0;
+
+out_free_pi_table:
+	sg_free_table_chained(&req->metadata_sgl->sg_table,
+			      NVME_INLINE_METADATA_SG_CNT);
+out_unmap_sg:
+	ib_dma_unmap_sg(ibdev, req->data_sgl.sg_table.sgl, req->data_sgl.nents,
+			rq_dma_dir(rq));
+out_free_table:
+	sg_free_table_chained(&req->data_sgl.sg_table, NVME_INLINE_SG_CNT);
+	return ret;
+}
+
+static void nvme_rdma_unmap_data(struct nvme_rdma_queue *queue,
+		struct request *rq)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_device *ibdev = dev->dev;
+	struct list_head *pool = &queue->qp->rdma_mrs;
+
+	if (!blk_rq_nr_phys_segments(rq))
+		return;
+
+	if (req->use_sig_mr)
+		pool = &queue->qp->sig_mrs;
+
+	if (req->mr) {
+		ib_mr_pool_put(queue->qp, pool, req->mr);
+		req->mr = NULL;
+	}
+
+	nvme_rdma_dma_unmap_req(ibdev, rq);
+}
+
+
+static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
+		struct request *rq, struct nvme_command *c)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_device *ibdev = dev->dev;
+	int pi_count = 0;
+	int count, ret;
+
+	req->num_sge = 1;
+	refcount_set(&req->ref, 2); /* send and recv completions */
+
+	c->common.flags |= NVME_CMD_SGL_METABUF;
+
+	if (!blk_rq_nr_phys_segments(rq))
+		return nvme_rdma_set_sg_null(c);
+
+	ret = nvme_rdma_dma_map_req(ibdev, rq, &count, &pi_count);
+	if (unlikely(ret))
+		return ret;
+
 	if (req->use_sig_mr) {
 		ret = nvme_rdma_map_sg_pi(queue, req, c, count, pi_count);
 		goto out;
@@ -1603,23 +1634,12 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
 	ret = nvme_rdma_map_sg_fr(queue, req, c, count);
 out:
 	if (unlikely(ret))
-		goto out_unmap_pi_sg;
+		goto out_dma_unmap_req;
 
 	return 0;
 
-out_unmap_pi_sg:
-	if (blk_integrity_rq(rq))
-		ib_dma_unmap_sg(ibdev, req->metadata_sgl->sg_table.sgl,
-				req->metadata_sgl->nents, rq_dma_dir(rq));
-out_free_pi_table:
-	if (blk_integrity_rq(rq))
-		sg_free_table_chained(&req->metadata_sgl->sg_table,
-				      NVME_INLINE_METADATA_SG_CNT);
-out_unmap_sg:
-	ib_dma_unmap_sg(ibdev, req->data_sgl.sg_table.sgl, req->data_sgl.nents,
-			rq_dma_dir(rq));
-out_free_table:
-	sg_free_table_chained(&req->data_sgl.sg_table, NVME_INLINE_SG_CNT);
+out_dma_unmap_req:
+	nvme_rdma_dma_unmap_req(ibdev, rq);
 	return ret;
 }
 
-- 
2.18.1