nvmet: add req cns error complete helper

We report error and complete the request when identify cns value is not
handled in nvmet_execute_identify(). This error reporting is also needed
for Zone Block Device backend for NVMeOF target.

Add a helper nvmet_req_cns_error_compplete() to report an error and
complete the request when idenitfy command cns not handled value.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/admin-cmd.c

@@ -637,10 +637,7 @@ static void nvmet_execute_identify(struct nvmet_req *req)
 		return nvmet_execute_identify_desclist(req);
 	}
 
-	pr_debug("unhandled identify cns %d on qid %d\n",
-	       req->cmd->identify.cns, req->sq->qid);
-	req->error_loc = offsetof(struct nvme_identify, cns);
-	nvmet_req_complete(req, NVME_SC_INVALID_FIELD | NVME_SC_DNR);
+	nvmet_req_cns_error_complete(req);
 }
 
 /*

drivers/nvme/target/nvmet.h

@@ -624,4 +624,12 @@ static inline bool nvmet_use_inline_bvec(struct nvmet_req *req)
 	       req->sg_cnt <= NVMET_MAX_INLINE_BIOVEC;
 }
 
+static inline void nvmet_req_cns_error_complete(struct nvmet_req *req)
+{
+	pr_debug("unhandled identify cns %d on qid %d\n",
+	       req->cmd->identify.cns, req->sq->qid);
+	req->error_loc = offsetof(struct nvme_identify, cns);
+	nvmet_req_complete(req, NVME_SC_INVALID_FIELD | NVME_SC_DNR);
+}
+
 #endif /* _NVMET_H */