[PATCH 5.4 1/2] nvme-pci: refactor nvme_unmap_data

[PATCH 5.4 1/2] nvme-pci: refactor nvme_unmap_data

[Marc Orr]

From: Christoph Hellwig <hch@lst.de>

commit 9275c206f88e5c49cb3e71932c81c8561083db9e upstream.

Split out three helpers from nvme_unmap_data that will allow finer grained
unwinding from nvme_map_data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
---
 drivers/nvme/host/pci.c | 77 ++++++++++++++++++++++++++---------------
 1 file changed, 49 insertions(+), 28 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 19e375b59f40..90dc86132007 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -528,50 +528,71 @@ static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
 	return true;
 }
 
-static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
+static void nvme_free_prps(struct nvme_dev *dev, struct request *req)
 {
-	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 	const int last_prp = dev->ctrl.page_size / sizeof(__le64) - 1;
-	dma_addr_t dma_addr = iod->first_dma, next_dma_addr;
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	dma_addr_t dma_addr = iod->first_dma;
 	int i;
 
-	if (iod->dma_len) {
-		dma_unmap_page(dev->dev, dma_addr, iod->dma_len,
-			       rq_dma_dir(req));
-		return;
+	for (i = 0; i < iod->npages; i++) {
+		__le64 *prp_list = nvme_pci_iod_list(req)[i];
+		dma_addr_t next_dma_addr = le64_to_cpu(prp_list[last_prp]);
+
+		dma_pool_free(dev->prp_page_pool, prp_list, dma_addr);
+		dma_addr = next_dma_addr;
 	}
 
-	WARN_ON_ONCE(!iod->nents);
+}
 
-	if (is_pci_p2pdma_page(sg_page(iod->sg)))
-		pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
-				    rq_dma_dir(req));
-	else
-		dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
+static void nvme_free_sgls(struct nvme_dev *dev, struct request *req)
+{
+	const int last_sg = SGES_PER_PAGE - 1;
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
+	dma_addr_t dma_addr = iod->first_dma;
+	int i;
 
+	for (i = 0; i < iod->npages; i++) {
+		struct nvme_sgl_desc *sg_list = nvme_pci_iod_list(req)[i];
+		dma_addr_t next_dma_addr = le64_to_cpu((sg_list[last_sg]).addr);
 
-	if (iod->npages == 0)
-		dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
-			dma_addr);
+		dma_pool_free(dev->prp_page_pool, sg_list, dma_addr);
+		dma_addr = next_dma_addr;
+	}
 
-	for (i = 0; i < iod->npages; i++) {
-		void *addr = nvme_pci_iod_list(req)[i];
+}
 
-		if (iod->use_sgl) {
-			struct nvme_sgl_desc *sg_list = addr;
+static void nvme_unmap_sg(struct nvme_dev *dev, struct request *req)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 
-			next_dma_addr =
-			    le64_to_cpu((sg_list[SGES_PER_PAGE - 1]).addr);
-		} else {
-			__le64 *prp_list = addr;
+	if (is_pci_p2pdma_page(sg_page(iod->sg)))
+		pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
+				    rq_dma_dir(req));
+	else
+		dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));
+}
 
-			next_dma_addr = le64_to_cpu(prp_list[last_prp]);
-		}
+static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
+{
+	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 
-		dma_pool_free(dev->prp_page_pool, addr, dma_addr);
-		dma_addr = next_dma_addr;
+	if (iod->dma_len) {
+		dma_unmap_page(dev->dev, iod->first_dma, iod->dma_len,
+			       rq_dma_dir(req));
+		return;
 	}
 
+	WARN_ON_ONCE(!iod->nents);
+
+	nvme_unmap_sg(dev, req);
+	if (iod->npages == 0)
+		dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
+			      iod->first_dma);
+	else if (iod->use_sgl)
+		nvme_free_sgls(dev, req);
+	else
+		nvme_free_prps(dev, req);
 	mempool_free(iod->sg, dev->iod_mempool);
 }
 
-- 
2.30.1.766.gb4fecdf3b7-goog

[PATCH 5.4 2/2] nvme-pci: fix error unwind in nvme_map_data

[Marc Orr]

From: Christoph Hellwig <hch@lst.de>

commit fa0732168fa1369dd089e5b06d6158a68229f7b7 upstream.

Properly unwind step by step using refactored helpers from nvme_unmap_data
to avoid a potential double dma_unmap on a mapping failure.

Fixes: 7fe07d14f71f ("nvme-pci: merge nvme_free_iod into nvme_unmap_data")
Reported-by: Marc Orr <marcorr@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
---
 drivers/nvme/host/pci.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 90dc86132007..abc342db3b33 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -669,7 +669,7 @@ static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
 			__le64 *old_prp_list = prp_list;
 			prp_list = dma_pool_alloc(pool, GFP_ATOMIC, &prp_dma);
 			if (!prp_list)
-				return BLK_STS_RESOURCE;
+				goto free_prps;
 			list[iod->npages++] = prp_list;
 			prp_list[0] = old_prp_list[i - 1];
 			old_prp_list[i - 1] = cpu_to_le64(prp_dma);
@@ -689,14 +689,14 @@ static blk_status_t nvme_pci_setup_prps(struct nvme_dev *dev,
 		dma_addr = sg_dma_address(sg);
 		dma_len = sg_dma_len(sg);
 	}
-
 done:
 	cmnd->dptr.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
 	cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma);
-
 	return BLK_STS_OK;
-
- bad_sgl:
+free_prps:
+	nvme_free_prps(dev, req);
+	return BLK_STS_RESOURCE;
+bad_sgl:
 	WARN(DO_ONCE(nvme_print_sgl, iod->sg, iod->nents),
 			"Invalid SGL for payload:%d nents:%d\n",
 			blk_rq_payload_bytes(req), iod->nents);
@@ -768,7 +768,7 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
 
 			sg_list = dma_pool_alloc(pool, GFP_ATOMIC, &sgl_dma);
 			if (!sg_list)
-				return BLK_STS_RESOURCE;
+				goto free_sgls;
 
 			i = 0;
 			nvme_pci_iod_list(req)[iod->npages++] = sg_list;
@@ -781,6 +781,9 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
 	} while (--entries > 0);
 
 	return BLK_STS_OK;
+free_sgls:
+	nvme_free_sgls(dev, req);
+	return BLK_STS_RESOURCE;
 }
 
 static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev,
@@ -849,7 +852,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 	sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
 	iod->nents = blk_rq_map_sg(req->q, req, iod->sg);
 	if (!iod->nents)
-		goto out;
+		goto out_free_sg;
 
 	if (is_pci_p2pdma_page(sg_page(iod->sg)))
 		nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
@@ -858,16 +861,21 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 		nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
 					     rq_dma_dir(req), DMA_ATTR_NO_WARN);
 	if (!nr_mapped)
-		goto out;
+		goto out_free_sg;
 
 	iod->use_sgl = nvme_pci_use_sgls(dev, req);
 	if (iod->use_sgl)
 		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)
-		nvme_unmap_data(dev, req);
+		goto out_unmap_sg;
+	return BLK_STS_OK;
+
+out_unmap_sg:
+	nvme_unmap_sg(dev, req);
+out_free_sg:
+	mempool_free(iod->sg, dev->iod_mempool);
 	return ret;
 }
 
-- 
2.30.1.766.gb4fecdf3b7-goog

Re: [PATCH 5.4 1/2] nvme-pci: refactor nvme_unmap_data

[Greg KH]

On Tue, Mar 02, 2021 at 05:39:10PM +0000, Marc Orr wrote:
> From: Christoph Hellwig <hch@lst.de>
> 
> commit 9275c206f88e5c49cb3e71932c81c8561083db9e upstream.
> 
> Split out three helpers from nvme_unmap_data that will allow finer grained
> unwinding from nvme_map_data.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Keith Busch <kbusch@kernel.org>
> Reviewed-by: Marc Orr <marcorr@google.com>
> Signed-off-by: Marc Orr <marcorr@google.com>
> ---
>  drivers/nvme/host/pci.c | 77 ++++++++++++++++++++++++++---------------
>  1 file changed, 49 insertions(+), 28 deletions(-)

Both now queued up, thanks.

greg k-h