Merge branch 'ref_tracker-add-ability-to-register-a-debugfs-file-for-a-ref_tracker_dir'

Jeff Layton says:

====================
ref_tracker: add ability to register a debugfs file for a ref_tracker_dir

For those just joining in, this series adds a new top-level
"ref_tracker" debugfs directory, and has each ref_tracker_dir register a
file in there as part of its initialization. It also adds the ability to
register a symlink with a more human-usable name that points to the
file, and does some general cleanup of how the ref_tracker object names
are handled.

v14: https://lore.kernel.org/20250610-reftrack-dbgfs-v14-0-efb532861428@kernel.org
v13: https://lore.kernel.org/20250603-reftrack-dbgfs-v13-0-7b2a425019d8@kernel.org
v12: https://lore.kernel.org/20250529-reftrack-dbgfs-v12-0-11b93c0c0b6e@kernel.org
v11: https://lore.kernel.org/20250528-reftrack-dbgfs-v11-0-94ae0b165841@kernel.org
v10: https://lore.kernel.org/20250527-reftrack-dbgfs-v10-0-dc55f7705691@kernel.org
v9: https://lore.kernel.org/20250509-reftrack-dbgfs-v9-0-8ab888a4524d@kernel.org
v8: https://lore.kernel.org/20250507-reftrack-dbgfs-v8-0-607717d3bb98@kernel.org
v7: https://lore.kernel.org/20250505-reftrack-dbgfs-v7-0-f78c5d97bcca@kernel.org
v6: https://lore.kernel.org/20250430-reftrack-dbgfs-v6-0-867c29aff03a@kernel.org
v5: https://lore.kernel.org/20250428-reftrack-dbgfs-v5-0-1cbbdf2038bd@kernel.org
v4: https://lore.kernel.org/20250418-reftrack-dbgfs-v4-0-5ca5c7899544@kernel.org
v3: https://lore.kernel.org/20250417-reftrack-dbgfs-v3-0-c3159428c8fb@kernel.org
v2: https://lore.kernel.org/20250415-reftrack-dbgfs-v2-0-b18c4abd122f@kernel.org
v1: https://lore.kernel.org/20250414-reftrack-dbgfs-v1-0-f03585832203@kernel.org
====================

Link: https://patch.msgid.link/20250618-reftrack-dbgfs-v15-0-24fc37ead144@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 46 insertions, 4 deletions

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index 8eac4f3d5254..d10563afd91c 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -6,6 +6,8 @@
 #include <linux/spinlock.h>
 #include <linux/stackdepot.h>
 
+#define __ostream_printf __printf(2, 3)
+
 struct ref_tracker;
 
 struct ref_tracker_dir {
@@ -17,15 +19,45 @@ struct ref_tracker_dir {
 	bool			dead;
 	struct list_head	list; /* List of active trackers */
 	struct list_head	quarantine; /* List of dead trackers */
-	char			name[32];
+	const char		*class; /* object classname */
 #endif
 };
 
 #ifdef CONFIG_REF_TRACKER
 
+#ifdef CONFIG_DEBUG_FS
+
+void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir);
+void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...);
+
+#else /* CONFIG_DEBUG_FS */
+
+static inline void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir)
+{
+}
+
+static inline __ostream_printf
+void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...)
+{
+}
+
+#endif /* CONFIG_DEBUG_FS */
+
+/**
+ * ref_tracker_dir_init - initialize a ref_tracker dir
+ * @dir: ref_tracker_dir to be initialized
+ * @quarantine_count: max number of entries to be tracked
+ * @class: pointer to static string that describes object type
+ *
+ * Initialize a ref_tracker_dir. If debugfs is configured, then a file
+ * will also be created for it under the top-level ref_tracker debugfs
+ * directory.
+ *
+ * Note that @class must point to a static string.
+ */
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
-					const char *name)
+					const char *class)
 {
 	INIT_LIST_HEAD(&dir->list);
 	INIT_LIST_HEAD(&dir->quarantine);
@@ -34,7 +66,8 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 	dir->dead = false;
 	refcount_set(&dir->untracked, 1);
 	refcount_set(&dir->no_tracker, 1);
-	strscpy(dir->name, name, sizeof(dir->name));
+	dir->class = class;
+	ref_tracker_dir_debugfs(dir);
 	stack_depot_init();
 }
 
@@ -58,7 +91,16 @@ int ref_tracker_free(struct ref_tracker_dir *dir,
 
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
-					const char *name)
+					const char *class)
+{
+}
+
+static inline void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir)
+{
+}
+
+static inline __ostream_printf
+void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...)
 {
 }