[PATCH AUTOSEL 6.1 03/14] nvme: adjust multiples of NVME_CTRL_PAGE_SIZE in offset

Sasha Levin
2024-06-05T12:05:00Z

From: Kundan Kumar <kundan.kumar@samsung.com>

[ Upstream commit 1bd293fcf3af84674e82ed022c049491f3768840 ]

bio_vec start offset may be relatively large particularly when large
folio gets added to the bio. A bigger offset will result in avoiding the
single-segment mapping optimization and end up using expensive
mempool_alloc further.

Rather than using absolute value, adjust bv_offset by
NVME_CTRL_PAGE_SIZE while checking if segment can be fitted into one/two
PRP entries.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/pci.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 5ff09f2cacab7..32e89ea853a47 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -824,7 +824,8 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
struct bio_vec bv = req_bvec(req);

if (!is_pci_p2pdma_page(bv.bv_page)) {
- if (bv.bv_offset + bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
+ if ((bv.bv_offset & (NVME_CTRL_PAGE_SIZE - 1)) +
+ bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
return nvme_setup_prp_simple(dev, req,
&cmnd->rw, &bv);

--
2.43.0