On 2021-01-28 00:38, Jianxiong Gao wrote:
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
---
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 it were possible for this to fail, you might leak the DMA mapping
here. However if dev->dma_parms somehow disappeared since a dozen lines
above then I think you've got far bigger problems anyway.
That said, do you really need to keep toggling this back and forth all
the time? Even if the device does make other mappings elsewhere that
don't necessarily need the same strict alignment, would it be
significantly harmful just to set it once at probe and leave it in place
anyway?
Robin.
+ }
if (!nr_mapped)
goto out_free_sg;
