From: Leon Romanovsky <leonro@nvidia.com>

Block layer maps MMIO memory through dma_map_phys() interface
with help of DMA_ATTR_MMIO attribute. There is a need to unmap
that memory with the appropriate unmap function, something which
wasn't possible before adding new REQ attribute to block layer in
previous patch.

Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/nvme/host/pci.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c916176bd9f0..2e9fb3c7bc09 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -689,11 +689,15 @@ static void nvme_free_prps(struct request *req)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
+	unsigned int attrs = 0;
 	unsigned int i;
 
+	if (req->cmd_flags & REQ_MMIO)
+		attrs |= DMA_ATTR_MMIO;
+
 	for (i = 0; i < iod->nr_dma_vecs; i++)
-		dma_unmap_page(nvmeq->dev->dev, iod->dma_vecs[i].addr,
-				iod->dma_vecs[i].len, rq_dma_dir(req));
+		dma_unmap_phys(nvmeq->dev->dev, iod->dma_vecs[i].addr,
+				iod->dma_vecs[i].len, rq_dma_dir(req), attrs);
 	mempool_free(iod->dma_vecs, nvmeq->dev->dmavec_mempool);
 }
 
@@ -704,16 +708,20 @@ static void nvme_free_sgls(struct request *req, struct nvme_sgl_desc *sge,
 	enum dma_data_direction dir = rq_dma_dir(req);
 	unsigned int len = le32_to_cpu(sge->length);
 	struct device *dma_dev = nvmeq->dev->dev;
+	unsigned int attrs = 0;
 	unsigned int i;
 
+	if (req->cmd_flags & REQ_MMIO)
+		attrs |= DMA_ATTR_MMIO;
+
 	if (sge->type == (NVME_SGL_FMT_DATA_DESC << 4)) {
-		dma_unmap_page(dma_dev, le64_to_cpu(sge->addr), len, dir);
+		dma_unmap_phys(dma_dev, le64_to_cpu(sge->addr), len, dir, attrs);
 		return;
 	}
 
 	for (i = 0; i < len / sizeof(*sg_list); i++)
-		dma_unmap_page(dma_dev, le64_to_cpu(sg_list[i].addr),
-			le32_to_cpu(sg_list[i].length), dir);
+		dma_unmap_phys(dma_dev, le64_to_cpu(sg_list[i].addr),
+			le32_to_cpu(sg_list[i].length), dir, attrs);
 }
 
 static void nvme_unmap_metadata(struct request *req)

-- 
2.51.0

On Fri, Oct 17, 2025 at 08:31:59AM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> Block layer maps MMIO memory through dma_map_phys() interface
> with help of DMA_ATTR_MMIO attribute. There is a need to unmap
> that memory with the appropriate unmap function, something which
> wasn't possible before adding new REQ attribute to block layer in
> previous patch.

DMA_ATTR_MMIO only gets set in the following patch as far as I can
tell.

The more logical way would be to simply convert to dma_unmap_phys
here and then add the flag in one go as suggested last round.

On Fri, Oct 17, 2025 at 08:20:08AM +0200, Christoph Hellwig wrote:
> On Fri, Oct 17, 2025 at 08:31:59AM +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@nvidia.com>
> > 
> > Block layer maps MMIO memory through dma_map_phys() interface
> > with help of DMA_ATTR_MMIO attribute. There is a need to unmap
> > that memory with the appropriate unmap function, something which
> > wasn't possible before adding new REQ attribute to block layer in
> > previous patch.
> 
> DMA_ATTR_MMIO only gets set in the following patch as far as I can
> tell.
> 
> The more logical way would be to simply convert to dma_unmap_phys
> here and then add the flag in one go as suggested last round.

Done, thanks