[PATCH 21/23] nvmet: add context annotation for integrity params in struct nvmet_ns

[Nilay Shroff <nilay@linux.ibm.com>]

The nvmet_ns::pi_type and nvmet_ns::metadata_size fields are protected
by nvmet_subsys::lock. Annotate them with __guarded_by(&subsys->lock)
to allow the Clang context analyzer to validate accesses to these fields.

Some request-processing and I/O paths access these fields without
holding subsys->lock. This is safe because the namespace reference held
by the request prevents the integrity parameters from being modified
while I/O is in flight. However, the context analyzer cannot express
this access pattern directly.

Introduce nvmet_ns_pi_type() and nvmet_ns_metadata_size() as inline
helpers annotated with __context_unsafe() to allow these lockless
accesses without triggering context analyzer warnings.

Use these helpers in the namespace identify path, metadata length
calculation, PI capability check, and RDMA signature attribute setup.

Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
---
 drivers/nvme/target/admin-cmd.c |  4 ++--
 drivers/nvme/target/nvmet.h     | 13 +++++++++----
 drivers/nvme/target/rdma.c      |  2 +-
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index b8015054de46..e40fc361f5b6 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -943,9 +943,9 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 			  NVME_NS_DPC_PI_TYPE1 | NVME_NS_DPC_PI_TYPE2 |
 			  NVME_NS_DPC_PI_TYPE3;
 		id->mc = NVME_MC_EXTENDED_LBA;
-		id->dps = req->ns->pi_type;
+		id->dps = nvmet_ns_pi_type(req->ns);
 		id->flbas = NVME_NS_FLBAS_META_EXT;
-		id->lbaf[0].ms = cpu_to_le16(req->ns->metadata_size);
+		id->lbaf[0].ms = cpu_to_le16(nvmet_ns_metadata_size(req->ns));
 	}
 
 	if (nvmet_ns_readonly(req->ns))
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 9e7a3992bb76..082d848ea2b0 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -189,8 +189,10 @@ struct nvmet_ns {
 		__guarded_by(&subsys->lock);
 	int			use_p2pmem
 		__guarded_by(&subsys->lock);
-	int			pi_type;
-	int			metadata_size;
+	int			pi_type
+		__guarded_by(&subsys->lock);
+	int			metadata_size
+		__guarded_by(&subsys->lock);
 	u8			csi;
 	struct nvmet_pr		pr;
 	struct xarray		pr_per_ctrl_refs;
@@ -221,6 +223,8 @@ NVMET_NS_ACCESSOR(u8 *, nguid)
 NVMET_NS_ACCESSOR(uuid_t, uuid)
 NVMET_NS_ACCESSOR(bool, buffered_io)
 NVMET_NS_ACCESSOR(const char *, device_path)
+NVMET_NS_ACCESSOR(int, pi_type)
+NVMET_NS_ACCESSOR(int, metadata_size)
 
 /*
  * These accessors use data_race() and READ_ONCE() to allow lockless access to
@@ -830,7 +834,7 @@ static inline u32 nvmet_rw_metadata_len(struct nvmet_req *req)
 	if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY))
 		return 0;
 	return ((u32)le16_to_cpu(req->cmd->rw.length) + 1) *
-			req->ns->metadata_size;
+			nvmet_ns_metadata_size(req->ns);
 }
 
 static inline u32 nvmet_dsm_len(struct nvmet_req *req)
@@ -1010,7 +1014,8 @@ static inline bool nvmet_ns_has_pi(struct nvmet_ns *ns)
 {
 	if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY))
 		return false;
-	return ns->pi_type && ns->metadata_size == sizeof(struct t10_pi_tuple);
+	return nvmet_ns_pi_type(ns) &&
+	       nvmet_ns_metadata_size(ns) == sizeof(struct t10_pi_tuple);
 }
 
 static inline __le64 nvmet_sect_to_lba(struct nvmet_ns *ns, sector_t sect)
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 0b351d39340c..2cec457f12fd 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -591,7 +591,7 @@ static void nvmet_rdma_set_sig_attrs(struct nvmet_req *req,
 {
 	struct nvme_command *cmd = req->cmd;
 	u16 control = le16_to_cpu(cmd->rw.control);
-	u8 pi_type = req->ns->pi_type;
+	u8 pi_type = nvmet_ns_pi_type(req->ns);
 	struct blk_integrity *bi;
 
 	bi = bdev_get_integrity(nvmet_ns_bdev(req->ns));
-- 
2.53.0