[RFC 2/7] nvme: allow integrity on extended metadata formats

[Keith Busch]

The block integrity subsystem knows how to construct protection
information buffers with metadata beyond the protection information
fields. Remove the driver restriction.

Note, this can only work if the PI field appears first in the metadata,
as the integrity subsystem doesn't update guard tags on preceding
metadata.

Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 drivers/nvme/host/core.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 5e0bfda04bd7..b3eabf6a08b9 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1726,12 +1726,9 @@ static int nvme_configure_metadata(struct nvme_ns *ns, struct nvme_id_ns *id)
 {
 	struct nvme_ctrl *ctrl = ns->ctrl;
 
-	/*
-	 * The PI implementation requires the metadata size to be equal to the
-	 * t10 pi tuple size.
-	 */
 	ns->ms = le16_to_cpu(id->lbaf[id->flbas & NVME_NS_FLBAS_LBA_MASK].ms);
-	if (ns->ms == sizeof(struct t10_pi_tuple))
+	if (id->dps & NVME_NS_DPS_PI_FIRST ||
+	    ns->ms == sizeof(struct t10_pi_tuple))
 		ns->pi_type = id->dps & NVME_NS_DPS_PI_MASK;
 	else
 		ns->pi_type = 0;
-- 
2.25.4