[PATCH 5.4 26/32] nvme: check the PRINFO bit before deciding the host buffer length

[Greg Kroah-Hartman]

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 7a964271959d8..c2cabd77884bf 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1295,8 +1295,21 @@ 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->ext) {
 		length += meta_len;
-- 
2.27.0