[PATCH 3/3] Adding device_dma_parameters->offset_preserve_mask to NVMe driver.

Jianxiong Gao
2021-01-28T00:42:10Z

NVMe driver relies on the address offset to function properly.
This patch adds the offset preserve mask to NVMe driver when mapping
via dma_map_sg_attrs and unmapping via nvme_unmap_sg. The mask
depends on the page size defined by CC.MPS register of NVMe
controller.

Signed-off-by: Jianxiong Gao <jxgao@google.com>
---
drivers/nvme/host/pci.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 856aa31931c1..0b23f04068be 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -580,12 +580,15 @@ static void nvme_free_sgls(struct nvme_dev *dev, struct request *req)
static void nvme_unmap_sg(struct nvme_dev *dev, struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
-
+ if (dma_set_page_offset_mask(dev->dev, NVME_CTRL_PAGE_SIZE - 1))
+ dev_warn(dev->dev, "dma_set_page_offset_mask failed to set offset\n");
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));
+ if (dma_set_page_offset_mask(dev->dev, 0))
+ dev_warn(dev->dev, "dma_set_page_offset_mask failed to reset offset\n");
}

static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
@@ -842,7 +845,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
blk_status_t ret = BLK_STS_RESOURCE;
- int nr_mapped;
+ int nr_mapped, offset_ret;

if (blk_rq_nr_phys_segments(req) == 1) {
struct bio_vec bv = req_bvec(req);
@@ -868,12 +871,24 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
if (!iod->nents)
goto out_free_sg;

+ offset_ret = dma_set_page_offset_mask(dev->dev, NVME_CTRL_PAGE_SIZE - 1);
+ if (offset_ret) {
+ dev_warn(dev->dev, "dma_set_page_offset_mask failed to set offset\n");
+ goto out_free_sg;
+ }
+
if (is_pci_p2pdma_page(sg_page(iod->sg)))
nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN);
else
nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
rq_dma_dir(req), DMA_ATTR_NO_WARN);
+
+ offset_ret = dma_set_page_offset_mask(dev->dev, 0);
+ if (offset_ret) {
+ dev_warn(dev->dev, "dma_set_page_offset_mask failed to reset offset\n");
+ goto out_free_sg;
+ }
if (!nr_mapped)
goto out_free_sg;

--
2.27.0