[PATCH v2 1/2] nvmet: add namespace-level debugfs directory

Add per-namespace debugfs directory support under the subsystem debugfs
directory. Each enabled namespace gets a ns<nsid>/ directory created
during nvmet_ns_enable() and removed during nvmet_ns_disable().

This provides the infrastructure for exposing namespace-specific debug
information in subsequent patches.

Signed-off-by: Guixin Liu <[email protected]>
---
 drivers/nvme/target/core.c    |  2 ++
 drivers/nvme/target/debugfs.c | 21 +++++++++++++++++++++
 drivers/nvme/target/debugfs.h |  5 +++++
 drivers/nvme/target/nvmet.h   |  3 +++
 4 files changed, 31 insertions(+)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 62dd59b9aa4f..9752913e05c6 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -616,6 +616,7 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
 	nvmet_ns_changed(subsys, ns->nsid);
 	ns->enabled = true;
 	xa_set_mark(&subsys->namespaces, ns->nsid, NVMET_NS_ENABLED);
+	nvmet_debugfs_ns_setup(ns);
 	ret = 0;
 out_unlock:
 	mutex_unlock(&subsys->lock);
@@ -642,6 +643,7 @@ void nvmet_ns_disable(struct nvmet_ns *ns)
 
 	ns->enabled = false;
 	xa_clear_mark(&subsys->namespaces, ns->nsid, NVMET_NS_ENABLED);
+	nvmet_debugfs_ns_free(ns);
 
 	list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry)
 		pci_dev_put(radix_tree_delete(&ctrl->p2p_ns_map, ns->nsid));
diff --git a/drivers/nvme/target/debugfs.c b/drivers/nvme/target/debugfs.c
index 5dcbd5aa86e1..e6f51eb59010 100644
--- a/drivers/nvme/target/debugfs.c
+++ b/drivers/nvme/target/debugfs.c
@@ -153,6 +153,27 @@ static int nvmet_ctrl_tls_concat_show(struct seq_file *m, void *p)
 NVMET_DEBUGFS_ATTR(nvmet_ctrl_tls_concat);
 #endif
 
+void nvmet_debugfs_ns_setup(struct nvmet_ns *ns)
+{
+	char name[16];
+	struct dentry *parent = ns->subsys->debugfs_dir;
+
+	if (!parent)
+		return;
+	snprintf(name, sizeof(name), "ns%u", ns->nsid);
+	ns->debugfs_dir = debugfs_create_dir(name, parent);
+	if (IS_ERR(ns->debugfs_dir)) {
+		ns->debugfs_dir = NULL;
+		return;
+	}
+}
+
+void nvmet_debugfs_ns_free(struct nvmet_ns *ns)
+{
+	debugfs_remove_recursive(ns->debugfs_dir);
+	ns->debugfs_dir = NULL;
+}
+
 int nvmet_debugfs_ctrl_setup(struct nvmet_ctrl *ctrl)
 {
 	char name[32];
diff --git a/drivers/nvme/target/debugfs.h b/drivers/nvme/target/debugfs.h
index cfb8bbf6a297..b559d254fc2a 100644
--- a/drivers/nvme/target/debugfs.h
+++ b/drivers/nvme/target/debugfs.h
@@ -14,6 +14,8 @@ int nvmet_debugfs_subsys_setup(struct nvmet_subsys *subsys);
 void nvmet_debugfs_subsys_free(struct nvmet_subsys *subsys);
 int nvmet_debugfs_ctrl_setup(struct nvmet_ctrl *ctrl);
 void nvmet_debugfs_ctrl_free(struct nvmet_ctrl *ctrl);
+void nvmet_debugfs_ns_setup(struct nvmet_ns *ns);
+void nvmet_debugfs_ns_free(struct nvmet_ns *ns);
 
 int __init nvmet_init_debugfs(void);
 void nvmet_exit_debugfs(void);
@@ -30,6 +32,9 @@ static inline int nvmet_debugfs_ctrl_setup(struct nvmet_ctrl *ctrl)
 }
 static inline void nvmet_debugfs_ctrl_free(struct nvmet_ctrl *ctrl) {}
 
+static inline void nvmet_debugfs_ns_setup(struct nvmet_ns *ns) {}
+static inline void nvmet_debugfs_ns_free(struct nvmet_ns *ns) {}
+
 static inline int __init nvmet_init_debugfs(void)
 {
     return 0;
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 3305a88684ec..142a78d9160f 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -128,6 +128,9 @@ struct nvmet_ns {
 	u8			csi;
 	struct nvmet_pr		pr;
 	struct xarray		pr_per_ctrl_refs;
+#ifdef CONFIG_NVME_TARGET_DEBUGFS
+	struct dentry		*debugfs_dir;
+#endif
 };
 
 static inline struct nvmet_ns *to_nvmet_ns(struct config_item *item)
-- 
2.43.7