[PATCH 5.10 39/57] nvme: check the PRINFO bit before deciding the host buffer length

From: Greg Kroah-Hartman
Date: Fri Feb 05 2021 - 17:37:28 EST


From: Revanth Rajashekar <revanth.rajashekar@xxxxxxxxx>

[ Upstream commit 4d6b1c95b974761c01cbad92321b82232b66d2a2 ]

According to NVMe spec v1.4, section 8.3.1, the PRINFO bit and
the metadata size play a vital role in deteriming the host buffer size.

If PRIFNO bit is set and MS==8, the host doesn't add the metadata buffer,
instead the controller adds it.

Signed-off-by: Revanth Rajashekar <revanth.rajashekar@xxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/nvme/host/core.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 34cb59b2fcd67..4ec5f05dabe1d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1489,8 +1489,21 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
}

length = (io.nblocks + 1) << ns->lba_shift;
- meta_len = (io.nblocks + 1) * ns->ms;
- metadata = nvme_to_user_ptr(io.metadata);
+
+ if ((io.control & NVME_RW_PRINFO_PRACT) &&
+ ns->ms == sizeof(struct t10_pi_tuple)) {
+ /*
+ * Protection information is stripped/inserted by the
+ * controller.
+ */
+ if (nvme_to_user_ptr(io.metadata))
+ return -EINVAL;
+ meta_len = 0;
+ metadata = NULL;
+ } else {
+ meta_len = (io.nblocks + 1) * ns->ms;
+ metadata = nvme_to_user_ptr(io.metadata);
+ }

if (ns->features & NVME_NS_EXT_LBAS) {
length += meta_len;
--
2.27.0