[PATCH V2 01/11] nvmet: zeroout id-ns buffer for invalid nsid

[Chaitanya Kulkarni]

According to spec :-
"5.15.2.7 Identify Namespace data structure for an Allocated Namespace
ID (CNS 11h) The Identify Namespace data structure (refer to Figure 245)
is returned to the host for the namespace specified in the Namespace
Identifier (NSID) field if it is an allocated NSID. If the specified
namespace is an unallocated NSID then the controller returns a zero
filled data structure."

Call nvmet_zero_sgl() when call to nvmet_find_namespace() fails and add
an explicit comment to specify the reason for zeroing the buffer which
is not common for the NVMe commands.

Fixes: bffcd507780e ("nvmet: set right status on error in id-ns handler")
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
---
 drivers/nvme/target/admin-cmd.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 613a4d8feac1..fa9a83541d51 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -482,10 +482,16 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 		goto out;
 	}
 
-	/* return an all zeroed buffer if we can't find an active namespace */
 	req->ns = nvmet_find_namespace(ctrl, req->cmd->identify.nsid);
 	if (!req->ns) {
 		status = NVME_SC_INVALID_NS;
+		/*
+		 * According to spec : If the specified namespace is
+		 * an unallocated NSID then the controller returns a zero filled
+		 * data structure. Also don't override the error status as invalid
+		 * namespace takes priority over the failed zeroout buffer case.
+		 */
+		nvmet_zero_sgl(req, 0, sizeof(*id));
 		goto done;
 	}
 
@@ -539,10 +545,11 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 
 	if (req->ns->readonly)
 		id->nsattr |= (1 << 0);
-done:
+
 	if (!status)
 		status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
 
+done:
 	kfree(id);
 out:
 	nvmet_req_complete(req, status);
-- 
2.22.1