blk-mq-dma: require unmap caller provide p2p map type

In preparing for integrity dma mappings, we can't rely on the request
flag because data and metadata may have different mapping types.

Signed-off-by: Keith Busch <[email protected]>

Author: keithbusch

drivers/nvme/host/pci.c

@@ -261,6 +261,9 @@ enum nvme_iod_flags {
 
 	/* single segment dma mapping */
 	IOD_SINGLE_SEGMENT	= 1U << 2,
+
+	/* DMA mapped with PCI_P2PDMA_MAP_BUS_ADDR */
+	IOD_P2P_BUS_ADDR	= 1U << 3,
 };
 
 struct nvme_dma_vec {
@@ -725,7 +728,8 @@ static void nvme_unmap_data(struct request *req)
 		return;
 	}
 
-	if (!blk_rq_dma_unmap(req, dma_dev, &iod->dma_state, iod->total_len)) {
+	if (!blk_rq_dma_unmap(req, dma_dev, &iod->dma_state, iod->total_len,
+				iod->flags & IOD_P2P_BUS_ADDR)) {
 		if (nvme_pci_cmd_use_sgl(&iod->cmd))
 			nvme_free_sgls(req);
 		else
@@ -1000,6 +1004,9 @@ static blk_status_t nvme_map_data(struct request *req)
 	if (!blk_rq_dma_map_iter_start(req, dev->dev, &iod->dma_state, &iter))
 		return iter.status;
 
+	if (iter.p2pdma.map == PCI_P2PDMA_MAP_BUS_ADDR)
+		iod->flags |= IOD_P2P_BUS_ADDR;
+
 	if (use_sgl == SGL_FORCED ||
 	    (use_sgl == SGL_SUPPORTED &&
 	     (sgl_threshold && nvme_pci_avg_seg_size(req) >= sgl_threshold)))

include/linux/blk-mq-dma.h

@@ -49,14 +49,15 @@ static inline bool blk_rq_dma_map_coalesce(struct dma_iova_state *state)
  * @dma_dev:	device to unmap from
  * @state:	DMA IOVA state
  * @mapped_len: number of bytes to unmap
+ * @is_p2p:	true if mapped with PCI_P2PDMA_MAP_BUS_ADDR
  *
  * Returns %false if the callers need to manually unmap every DMA segment
  * mapped using @iter or %true if no work is left to be done.
  */
 static inline bool blk_rq_dma_unmap(struct request *req, struct device *dma_dev,
-		struct dma_iova_state *state, size_t mapped_len)
+		struct dma_iova_state *state, size_t mapped_len, bool is_p2p)
 {
-	if (req->cmd_flags & REQ_P2PDMA)
+	if (is_p2p)
 		return true;
 
 	if (dma_use_iova(state)) {