nvmet: add nvmet_req_subsys() helper

Just like what we have to get the passthru ctrl from the req, add an
helper to get the subsystem associated with the nvmet_req() instead
of open coding the chain of structures.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/admin-cmd.c

@@ -683,7 +683,7 @@ static u16 nvmet_write_protect_flush_sync(struct nvmet_req *req)
 static u16 nvmet_set_feat_write_protect(struct nvmet_req *req)
 {
 	u32 write_protect = le32_to_cpu(req->cmd->common.cdw11);
-	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
+	struct nvmet_subsys *subsys = nvmet_req_subsys(req);
 	u16 status;
 
 	status = nvmet_req_find_ns(req);
@@ -742,7 +742,7 @@ u16 nvmet_set_feat_async_event(struct nvmet_req *req, u32 mask)
 
 void nvmet_execute_set_features(struct nvmet_req *req)
 {
-	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
+	struct nvmet_subsys *subsys = nvmet_req_subsys(req);
 	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
 	u32 cdw11 = le32_to_cpu(req->cmd->common.cdw11);
 	u16 status = 0;
@@ -786,7 +786,7 @@ void nvmet_execute_set_features(struct nvmet_req *req)
 
 static u16 nvmet_get_feat_write_protect(struct nvmet_req *req)
 {
-	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
+	struct nvmet_subsys *subsys = nvmet_req_subsys(req);
 	u32 result;
 
 	result = nvmet_req_find_ns(req);
@@ -816,7 +816,7 @@ void nvmet_get_feat_async_event(struct nvmet_req *req)
 
 void nvmet_execute_get_features(struct nvmet_req *req)
 {
-	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
+	struct nvmet_subsys *subsys = nvmet_req_subsys(req);
 	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
 	u16 status = 0;
 
@@ -923,7 +923,7 @@ u16 nvmet_parse_admin_cmd(struct nvmet_req *req)
 
 	if (nvme_is_fabrics(cmd))
 		return nvmet_parse_fabrics_cmd(req);
-	if (req->sq->ctrl->subsys->type == NVME_NQN_DISC)
+	if (nvmet_req_subsys(req)->type == NVME_NQN_DISC)
 		return nvmet_parse_discovery_cmd(req);
 
 	ret = nvmet_check_ctrl_status(req, cmd);

drivers/nvme/target/core.c

@@ -430,7 +430,7 @@ u16 nvmet_req_find_ns(struct nvmet_req *req)
 {
 	u32 nsid = le32_to_cpu(req->cmd->common.nsid);
 
-	req->ns = xa_load(&req->sq->ctrl->subsys->namespaces, nsid);
+	req->ns = xa_load(&nvmet_req_subsys(req)->namespaces, nsid);
 	if (unlikely(!req->ns)) {
 		req->error_loc = offsetof(struct nvme_common_command, nsid);
 		return NVME_SC_INVALID_NS | NVME_SC_DNR;

drivers/nvme/target/nvmet.h

@@ -551,6 +551,11 @@ static inline u32 nvmet_dsm_len(struct nvmet_req *req)
 		sizeof(struct nvme_dsm_range);
 }
 
+static inline struct nvmet_subsys *nvmet_req_subsys(struct nvmet_req *req)
+{
+	return req->sq->ctrl->subsys;
+}
+
 #ifdef CONFIG_NVME_TARGET_PASSTHRU
 void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys);
 int nvmet_passthru_ctrl_enable(struct nvmet_subsys *subsys);
@@ -585,7 +590,7 @@ static inline struct nvme_ctrl *nvmet_passthru_ctrl(struct nvmet_subsys *subsys)
 static inline struct nvme_ctrl *
 nvmet_req_passthru_ctrl(struct nvmet_req *req)
 {
-	return nvmet_passthru_ctrl(req->sq->ctrl->subsys);
+	return nvmet_passthru_ctrl(nvmet_req_subsys(req));
 }
 
 u16 errno_to_nvme_status(struct nvmet_req *req, int errno);

drivers/nvme/target/passthru.c

@@ -239,9 +239,9 @@ static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
 		}
 
 		q = ns->queue;
-		timeout = req->sq->ctrl->subsys->io_timeout;
+		timeout = nvmet_req_subsys(req)->io_timeout;
 	} else {
-		timeout = req->sq->ctrl->subsys->admin_timeout;
+		timeout = nvmet_req_subsys(req)->admin_timeout;
 	}
 
 	rq = nvme_alloc_request(q, req->cmd, 0);