nvmet: make nvmet_find_namespace() req based

The six callers of nvmet_find_namespace() duplicate the error log page
update and status setting code for each call on failure.

All callers are nvmet requests based functions, so we can pass req
to the nvmet_find_namesapce() & derive ctrl from req, that'll allow us
to update the error log page in nvmet_find_namespace(). Now that we
pass the request we can also get rid of the local variable in
nvmet_find_namespace() and use the req->ns and return the error code.

Replace the ctrl parameter with nvmet_req for nvmet_find_namespace(),
centralize the error log page update for non allocated namesapces, and
return uniform error for non-allocated namespace.

The nvmet_find_namespace() takes nsid parameter which is from NVMe
commands structures such as get_log_page, identify, rw and common. All
these commands have same offset for the nsid field.

Derive nsid from req->cmd->common.nsid) & remove the extra parameter
from the nvmet_find_namespace().

Lastly now we associate the ns to the req parameter that we pass to the
nvmet_find_namespace(), rename nvmet_find_namespace() to
nvmet_req_find_ns().

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/admin-cmd.c

@@ -75,15 +75,11 @@ static u16 nvmet_get_smart_log_nsid(struct nvmet_req *req,
 		struct nvme_smart_log *slog)
 {
 	u64 host_reads, host_writes, data_units_read, data_units_written;
+	u16 status;
 
-	req->ns = nvmet_find_namespace(req->sq->ctrl,
-				       req->cmd->get_log_page.nsid);
-	if (!req->ns) {
-		pr_err("Could not find namespace id : %d\n",
-				le32_to_cpu(req->cmd->get_log_page.nsid));
-		req->error_loc = offsetof(struct nvme_rw_command, nsid);
-		return NVME_SC_INVALID_NS | NVME_SC_DNR;
-	}
+	status = nvmet_req_find_ns(req);
+	if (status)
+		return status;
 
 	/* we don't have the right data for file backed ns */
 	if (!req->ns->bdev)
@@ -468,7 +464,7 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvme_id_ns *id;
-	u16 status = 0;
+	u16 status;
 
 	if (le32_to_cpu(req->cmd->identify.nsid) == NVME_NSID_ALL) {
 		req->error_loc = offsetof(struct nvme_identify, nsid);
@@ -483,8 +479,8 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
 	}
 
 	/* 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 = nvmet_req_find_ns(req);
+	if (status) {
 		status = 0;
 		goto done;
 	}
@@ -604,15 +600,12 @@ static u16 nvmet_copy_ns_identifier(struct nvmet_req *req, u8 type, u8 len,
 
 static void nvmet_execute_identify_desclist(struct nvmet_req *req)
 {
-	u16 status = 0;
 	off_t off = 0;
+	u16 status;
 
-	req->ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->identify.nsid);
-	if (!req->ns) {
-		req->error_loc = offsetof(struct nvme_identify, nsid);
-		status = NVME_SC_INVALID_NS | NVME_SC_DNR;
+	status = nvmet_req_find_ns(req);
+	if (status)
 		goto out;
-	}
 
 	if (memchr_inv(&req->ns->uuid, 0, sizeof(req->ns->uuid))) {
 		status = nvmet_copy_ns_identifier(req, NVME_NIDT_UUID,
@@ -692,13 +685,11 @@ 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;
-	u16 status = NVME_SC_FEATURE_NOT_CHANGEABLE;
+	u16 status;
 
-	req->ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->rw.nsid);
-	if (unlikely(!req->ns)) {
-		req->error_loc = offsetof(struct nvme_common_command, nsid);
-		return status = NVME_SC_INVALID_NS | NVME_SC_DNR;
-	}
+	status = nvmet_req_find_ns(req);
+	if (status)
+		return status;
 
 	mutex_lock(&subsys->lock);
 	switch (write_protect) {
@@ -799,11 +790,10 @@ static u16 nvmet_get_feat_write_protect(struct nvmet_req *req)
 	struct nvmet_subsys *subsys = req->sq->ctrl->subsys;
 	u32 result;
 
-	req->ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->common.nsid);
-	if (!req->ns)  {
-		req->error_loc = offsetof(struct nvme_common_command, nsid);
-		return NVME_SC_INVALID_NS | NVME_SC_DNR;
-	}
+	result = nvmet_req_find_ns(req);
+	if (result)
+		return result;
+
 	mutex_lock(&subsys->lock);
 	if (req->ns->readonly == true)
 		result = NVME_NS_WRITE_PROTECT;

drivers/nvme/target/core.c

@@ -417,15 +417,18 @@ void nvmet_stop_keep_alive_timer(struct nvmet_ctrl *ctrl)
 	cancel_delayed_work_sync(&ctrl->ka_work);
 }
 
-struct nvmet_ns *nvmet_find_namespace(struct nvmet_ctrl *ctrl, __le32 nsid)
+u16 nvmet_req_find_ns(struct nvmet_req *req)
 {
-	struct nvmet_ns *ns;
+	u32 nsid = le32_to_cpu(req->cmd->common.nsid);
 
-	ns = xa_load(&ctrl->subsys->namespaces, le32_to_cpu(nsid));
-	if (ns)
-		percpu_ref_get(&ns->ref);
+	req->ns = xa_load(&req->sq->ctrl->subsys->namespaces, nsid);
+	if (unlikely(!req->ns)) {
+		req->error_loc = offsetof(struct nvme_common_command, nsid);
+		return NVME_SC_INVALID_NS | NVME_SC_DNR;
+	}
 
-	return ns;
+	percpu_ref_get(&req->ns->ref);
+	return NVME_SC_SUCCESS;
 }
 
 static void nvmet_destroy_namespace(struct percpu_ref *ref)
@@ -862,11 +865,10 @@ static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
 	if (nvmet_req_passthru_ctrl(req))
 		return nvmet_parse_passthru_io_cmd(req);
 
-	req->ns = nvmet_find_namespace(req->sq->ctrl, cmd->rw.nsid);
-	if (unlikely(!req->ns)) {
-		req->error_loc = offsetof(struct nvme_common_command, nsid);
-		return NVME_SC_INVALID_NS | NVME_SC_DNR;
-	}
+	ret = nvmet_req_find_ns(req);
+	if (unlikely(ret))
+		return ret;
+
 	ret = nvmet_check_ana_state(req->port, req->ns);
 	if (unlikely(ret)) {
 		req->error_loc = offsetof(struct nvme_common_command, nsid);

drivers/nvme/target/nvmet.h

@@ -443,7 +443,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 void nvmet_subsys_put(struct nvmet_subsys *subsys);
 void nvmet_subsys_del_ctrls(struct nvmet_subsys *subsys);
 
-struct nvmet_ns *nvmet_find_namespace(struct nvmet_ctrl *ctrl, __le32 nsid);
+u16 nvmet_req_find_ns(struct nvmet_req *req);
 void nvmet_put_namespace(struct nvmet_ns *ns);
 int nvmet_ns_enable(struct nvmet_ns *ns);
 void nvmet_ns_disable(struct nvmet_ns *ns);