[PATCH v7 00/10] ref_tracker: add ability to register a debugfs file for a ref_tracker_dir

[PATCH v7 00/10] ref_tracker: add ability to register a debugfs file for a ref_tracker_dir

[Jeff Layton]

This one is quite a bit of a change from the last set. I've gone back to
auto-registering the debugfs files for every ref_tracker_dir. With this,
the callers should pass in a static string as a classname instead of an
individual name string that gets copied. The debugfs file is given a
name "class@%px" The output format is switched to print "class@%p"
instead of "name@%p".

To allow for human-readable names, I've added the ability to add a
symlink in the debugfs dir that can be set to an arbitrary name. This is
optional. I've only added them to the netns and i915 trackers in this
series.

Finally, with the above changes, we can eliminate the "name" field in
the ref_tracker_dir which shrinks it by 16 bytes on a 64 bit host.

The original plan was to merge this via the networking tree. That's
probably still doable but there are some display port and i915 changes
in here too. Note that those are untested, mostly because I don't have
the necessary hardware handy.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
Changes in v7:
- include net->net_cookie in netns symlink name
- add __ostream_printf to ref_tracker_dir_symlink() stub function
- remove unneeded #include of seq_file.h
- Link to v6: https://lore.kernel.org/r/20250430-reftrack-dbgfs-v6-0-867c29aff03a@kernel.org

Changes in v6:
- clean up kerneldoc comment for ref_tracker_dir_debugfs()
- add missing stub function for ref_tracker_dir_symlink()
- temporary __maybe_unused on ref_tracker_dir_seq_print() to silence compiler warning
- Link to v5: https://lore.kernel.org/r/20250428-reftrack-dbgfs-v5-0-1cbbdf2038bd@kernel.org

Changes in v5:
- add class string to each ref_tracker_dir
- auto-register debugfs file for every tracker in ref_tracker_dir_init
- add function to allow adding a symlink for each tracker
- add patches to create symlinks for netns's and i915 entries
- change output format to print class@%p instead of name@%p
- eliminate the name field in ref_tracker_dir
- fix off-by-one bug when NULL terminating name string
- Link to v4: https://lore.kernel.org/r/20250418-reftrack-dbgfs-v4-0-5ca5c7899544@kernel.org

Changes in v4:
- Drop patch to widen ref_tracker_dir_.name, use NAME_MAX+1 (256) instead since this only affects dentry name
- Link to v3: https://lore.kernel.org/r/20250417-reftrack-dbgfs-v3-0-c3159428c8fb@kernel.org

Changes in v3:
- don't overwrite dir->name in ref_tracker_dir_debugfs
- define REF_TRACKER_NAMESZ and use it when setting name
- Link to v2: https://lore.kernel.org/r/20250415-reftrack-dbgfs-v2-0-b18c4abd122f@kernel.org

Changes in v2:
- Add patch to do %pK -> %p conversion in ref_tracker.c
- Pass in output function to pr_ostream() instead of if statement
- Widen ref_tracker_dir.name to 64 bytes to accomodate unique names
- Eliminate error handling with debugfs manipulation
- Incorporate pointer value into netdev name
- Link to v1: https://lore.kernel.org/r/20250414-reftrack-dbgfs-v1-0-f03585832203@kernel.org

---
Jeff Layton (10):
      ref_tracker: don't use %pK in pr_ostream() output
      ref_tracker: add a top level debugfs directory for ref_tracker
      ref_tracker: have callers pass output function to pr_ostream()
      ref_tracker: add a static classname string to each ref_tracker_dir
      ref_tracker: allow pr_ostream() to print directly to a seq_file
      ref_tracker: automatically register a file in debugfs for a ref_tracker_dir
      ref_tracker: add a way to create a symlink to the ref_tracker_dir debugfs file
      net: add symlinks to ref_tracker_dir for netns
      i915: add ref_tracker_dir symlinks for each tracker
      ref_tracker: eliminate the ref_tracker_dir name field

 drivers/gpu/drm/display/drm_dp_tunnel.c |   2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c |   4 +-
 drivers/gpu/drm/i915/intel_wakeref.c    |   3 +-
 include/linux/ref_tracker.h             |  46 +++++++-
 lib/ref_tracker.c                       | 190 +++++++++++++++++++++++++++++---
 net/core/dev.c                          |   2 +-
 net/core/net_namespace.c                |  34 +++++-
 7 files changed, 255 insertions(+), 26 deletions(-)
---
base-commit: 5bc1018675ec28a8a60d83b378d8c3991faa5a27
change-id: 20250413-reftrack-dbgfs-3767b303e2fa

Best regards,
-- 
Jeff Layton <jlayton@kernel.org>

[PATCH v7 01/10] ref_tracker: don't use %pK in pr_ostream() output

[Jeff Layton]

As Thomas Weißschuh points out [1], it is now preferable to use %p
instead of hashed pointers with printk(), since raw pointers should no
longer be leaked into the kernel log. Change the ref_tracker
infrastructure to use %p instead of %pK in its formats.

[1]: https://lore.kernel.org/netdev/20250414-restricted-pointers-net-v1-0-12af0ce46cdd@linutronix.de/

Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 lib/ref_tracker.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index cf5609b1ca79361763abe5a3a98484a3ee591ff2..de71439e12a3bab6456910986fa611dfbdd97980 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -96,7 +96,7 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 
 	stats = ref_tracker_get_stats(dir, display_limit);
 	if (IS_ERR(stats)) {
-		pr_ostream(s, "%s@%pK: couldn't get stats, error %pe\n",
+		pr_ostream(s, "%s@%p: couldn't get stats, error %pe\n",
 			   dir->name, dir, stats);
 		return;
 	}
@@ -107,13 +107,13 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 		stack = stats->stacks[i].stack_handle;
 		if (sbuf && !stack_depot_snprint(stack, sbuf, STACK_BUF_SIZE, 4))
 			sbuf[0] = 0;
-		pr_ostream(s, "%s@%pK has %d/%d users at\n%s\n", dir->name, dir,
+		pr_ostream(s, "%s@%p has %d/%d users at\n%s\n", dir->name, dir,
 			   stats->stacks[i].count, stats->total, sbuf);
 		skipped -= stats->stacks[i].count;
 	}
 
 	if (skipped)
-		pr_ostream(s, "%s@%pK skipped reports about %d/%d users.\n",
+		pr_ostream(s, "%s@%p skipped reports about %d/%d users.\n",
 			   dir->name, dir, skipped, stats->total);
 
 	kfree(sbuf);

-- 
2.49.0

[PATCH v7 02/10] ref_tracker: add a top level debugfs directory for ref_tracker

[Jeff Layton]

Add a new "ref_tracker" directory in debugfs. Each individual refcount
tracker can register files under there to display info about
currently-held references.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 lib/ref_tracker.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index de71439e12a3bab6456910986fa611dfbdd97980..a66cde325920780cfe7529ea9d827d0ee943318d 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -12,6 +12,8 @@
 #define REF_TRACKER_STACK_ENTRIES 16
 #define STACK_BUF_SIZE 1024
 
+static struct dentry *ref_tracker_debug_dir = (struct dentry *)-ENOENT;
+
 struct ref_tracker {
 	struct list_head	head;   /* anchor into dir->list or dir->quarantine */
 	bool			dead;
@@ -273,3 +275,17 @@ int ref_tracker_free(struct ref_tracker_dir *dir,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(ref_tracker_free);
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+
+static int __init ref_tracker_debugfs_init(void)
+{
+	ref_tracker_debug_dir = debugfs_create_dir("ref_tracker", NULL);
+	if (IS_ERR(ref_tracker_debug_dir))
+		pr_warn("ref_tracker: unable to create debugfs ref_tracker directory: %pe\n",
+			ref_tracker_debug_dir);
+	return 0;
+}
+late_initcall(ref_tracker_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */

-- 
2.49.0

[PATCH v7 03/10] ref_tracker: have callers pass output function to pr_ostream()

[Jeff Layton]

In a later patch, we'll be adding a 3rd mechanism for outputting
ref_tracker info via seq_file. Instead of a conditional, have the caller
set a pointer to an output function in struct ostream. As part of this,
the log prefix must be explicitly passed in, as it's too late for the
pr_fmt macro.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 include/linux/ref_tracker.h |  2 ++
 lib/ref_tracker.c           | 51 ++++++++++++++++++++++++++++++++-------------
 2 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index 8eac4f3d52547ccbaf9dcd09962ce80d26fbdff8..a0a1ee43724ffa00e60c116be18e481bfe1d1455 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 {
diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index a66cde325920780cfe7529ea9d827d0ee943318d..510d927c785576fd90292d325d20a465d5f38079 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -65,21 +65,37 @@ ref_tracker_get_stats(struct ref_tracker_dir *dir, unsigned int limit)
 }
 
 struct ostream {
+	void __ostream_printf (*func)(struct ostream *stream, char *fmt, ...);
+	char *prefix;
 	char *buf;
 	int size, used;
 };
 
+static void __ostream_printf pr_ostream_log(struct ostream *stream, char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vprintk(fmt, args);
+	va_end(args);
+}
+
+static void __ostream_printf pr_ostream_buf(struct ostream *stream, char *fmt, ...)
+{
+	int ret, len = stream->size - stream->used;
+	va_list args;
+
+	va_start(args, fmt);
+	ret = vsnprintf(stream->buf + stream->used, len, fmt, args);
+	va_end(args);
+	stream->used += min(ret, len);
+}
+
 #define pr_ostream(stream, fmt, args...) \
 ({ \
 	struct ostream *_s = (stream); \
 \
-	if (!_s->buf) { \
-		pr_err(fmt, ##args); \
-	} else { \
-		int ret, len = _s->size - _s->used; \
-		ret = snprintf(_s->buf + _s->used, len, pr_fmt(fmt), ##args); \
-		_s->used += min(ret, len); \
-	} \
+	_s->func(_s, fmt, ##args); \
 })
 
 static void
@@ -98,8 +114,8 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 
 	stats = ref_tracker_get_stats(dir, display_limit);
 	if (IS_ERR(stats)) {
-		pr_ostream(s, "%s@%p: couldn't get stats, error %pe\n",
-			   dir->name, dir, stats);
+		pr_ostream(s, "%s%s@%p: couldn't get stats, error %pe\n",
+			   s->prefix, dir->name, dir, stats);
 		return;
 	}
 
@@ -109,14 +125,15 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 		stack = stats->stacks[i].stack_handle;
 		if (sbuf && !stack_depot_snprint(stack, sbuf, STACK_BUF_SIZE, 4))
 			sbuf[0] = 0;
-		pr_ostream(s, "%s@%p has %d/%d users at\n%s\n", dir->name, dir,
-			   stats->stacks[i].count, stats->total, sbuf);
+		pr_ostream(s, "%s%s@%p has %d/%d users at\n%s\n", s->prefix,
+			   dir->name, dir, stats->stacks[i].count,
+			   stats->total, sbuf);
 		skipped -= stats->stacks[i].count;
 	}
 
 	if (skipped)
-		pr_ostream(s, "%s@%p skipped reports about %d/%d users.\n",
-			   dir->name, dir, skipped, stats->total);
+		pr_ostream(s, "%s%s@%p skipped reports about %d/%d users.\n",
+			   s->prefix, dir->name, dir, skipped, stats->total);
 
 	kfree(sbuf);
 
@@ -126,7 +143,8 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 void ref_tracker_dir_print_locked(struct ref_tracker_dir *dir,
 				  unsigned int display_limit)
 {
-	struct ostream os = {};
+	struct ostream os = { .func = pr_ostream_log,
+			      .prefix = "ref_tracker: " };
 
 	__ref_tracker_dir_pr_ostream(dir, display_limit, &os);
 }
@@ -145,7 +163,10 @@ EXPORT_SYMBOL(ref_tracker_dir_print);
 
 int ref_tracker_dir_snprint(struct ref_tracker_dir *dir, char *buf, size_t size)
 {
-	struct ostream os = { .buf = buf, .size = size };
+	struct ostream os = { .func = pr_ostream_buf,
+			      .prefix = "ref_tracker: ",
+			      .buf = buf,
+			      .size = size };
 	unsigned long flags;
 
 	spin_lock_irqsave(&dir->lock, flags);

-- 
2.49.0

[PATCH v7 04/10] ref_tracker: add a static classname string to each ref_tracker_dir

[Jeff Layton]

A later patch in the series will be adding debugfs files for each
ref_tracker that get created in ref_tracker_dir_init(). The format will
be "class@%px". The current "name" string can vary between
ref_tracker_dir objects of the same type, so it's not suitable for this
purpose.

Add a new "class" string to the ref_tracker dir that describes the
the type of object (sans any individual info for that object).

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 drivers/gpu/drm/display/drm_dp_tunnel.c | 2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c | 3 ++-
 drivers/gpu/drm/i915/intel_wakeref.c    | 2 +-
 include/linux/ref_tracker.h             | 4 ++++
 lib/test_ref_tracker.c                  | 2 +-
 net/core/dev.c                          | 2 +-
 net/core/net_namespace.c                | 4 ++--
 7 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_tunnel.c b/drivers/gpu/drm/display/drm_dp_tunnel.c
index 90fe07a89260e21e78f2db7f57a90602be921a11..f2a8ef6abf34d89a642d7c7708c41e5b1dc9dece 100644
--- a/drivers/gpu/drm/display/drm_dp_tunnel.c
+++ b/drivers/gpu/drm/display/drm_dp_tunnel.c
@@ -1920,7 +1920,7 @@ drm_dp_tunnel_mgr_create(struct drm_device *dev, int max_group_count)
 	}
 
 #ifdef CONFIG_DRM_DISPLAY_DP_TUNNEL_STATE_DEBUG
-	ref_tracker_dir_init(&mgr->ref_tracker, 16, "dptun");
+	ref_tracker_dir_init(&mgr->ref_tracker, 16, "drm_dptun", "dptun");
 #endif
 
 	for (i = 0; i < max_group_count; i++) {
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 8d9f4c410546e4144d4bc8bbc6696f3bd9498848..3fdab3b44c08cea16ac2f73aafc2bea2ffbb19e7 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -59,7 +59,8 @@ static struct drm_i915_private *rpm_to_i915(struct intel_runtime_pm *rpm)
 
 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 {
-	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT, dev_name(rpm->kdev));
+	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT,
+			     "intel_runtime_pm", dev_name(rpm->kdev));
 }
 
 static intel_wakeref_t
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index 07e81be4d3920febece34709c63a63204a41583c..5269e64c58a49884f5d712557546272bfdeb8417 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -114,7 +114,7 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
 			 "wakeref.work", &key->work, 0);
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
-	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, name);
+	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, "intel_wakeref", name);
 #endif
 }
 
diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index a0a1ee43724ffa00e60c116be18e481bfe1d1455..3968f993db81e95c0d58c81454311841c1b9cd35 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -19,6 +19,7 @@ struct ref_tracker_dir {
 	bool			dead;
 	struct list_head	list; /* List of active trackers */
 	struct list_head	quarantine; /* List of dead trackers */
+	const char		*class; /* object classname */
 	char			name[32];
 #endif
 };
@@ -27,6 +28,7 @@ struct ref_tracker_dir {
 
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
+					const char *class,
 					const char *name)
 {
 	INIT_LIST_HEAD(&dir->list);
@@ -36,6 +38,7 @@ 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);
+	dir->class = class;
 	strscpy(dir->name, name, sizeof(dir->name));
 	stack_depot_init();
 }
@@ -60,6 +63,7 @@ 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 *class,
 					const char *name)
 {
 }
diff --git a/lib/test_ref_tracker.c b/lib/test_ref_tracker.c
index b983ceb12afcb84ad60360a1e6fec0072e78ef79..d263502a4c1db248f64a66a468e96c8e4cffab25 100644
--- a/lib/test_ref_tracker.c
+++ b/lib/test_ref_tracker.c
@@ -64,7 +64,7 @@ static int __init test_ref_tracker_init(void)
 {
 	int i;
 
-	ref_tracker_dir_init(&ref_dir, 100, "selftest");
+	ref_tracker_dir_init(&ref_dir, 100, "selftest", "selftest");
 
 	timer_setup(&test_ref_tracker_timer, test_ref_tracker_timer_func, 0);
 	mod_timer(&test_ref_tracker_timer, jiffies + 1);
diff --git a/net/core/dev.c b/net/core/dev.c
index 1be7cb73a6024fda6797b6dfc895e4ce25f43251..380d07bec15a1f62ed27c31a6e211e74f3a5561d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11620,7 +11620,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 
 	dev->priv_len = sizeof_priv;
 
-	ref_tracker_dir_init(&dev->refcnt_tracker, 128, name);
+	ref_tracker_dir_init(&dev->refcnt_tracker, 128, "netdev", name);
 #ifdef CONFIG_PCPU_DEV_REFCNT
 	dev->pcpu_refcnt = alloc_percpu(int);
 	if (!dev->pcpu_refcnt)
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index b0dfdf791ece5aa8fefdc2aea1ff4a9d9c399d72..008de9675ea98fa8c18628b2f1c3aee7f3ebc9c6 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -324,8 +324,8 @@ static __net_init void preinit_net(struct net *net, struct user_namespace *user_
 {
 	refcount_set(&net->passive, 1);
 	refcount_set(&net->ns.count, 1);
-	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net refcnt");
-	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net notrefcnt");
+	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net_refcnt", "net_refcnt");
+	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net_notrefcnt", "net_notrefcnt");
 
 	get_random_bytes(&net->hash_mix, sizeof(u32));
 	net->dev_base_seq = 1;

-- 
2.49.0

[PATCH v7 05/10] ref_tracker: allow pr_ostream() to print directly to a seq_file

[Jeff Layton]

Allow pr_ostream to also output directly to a seq_file without an
intermediate buffer. The first caller of +ref_tracker_dir_seq_print()
will come in a later patch, so mark that __maybe_unused for now. That
designation will be removed once it is used.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 lib/ref_tracker.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index 510d927c785576fd90292d325d20a465d5f38079..66a765cdfc471968fd6434dafc5b654962f20667 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -8,6 +8,7 @@
 #include <linux/slab.h>
 #include <linux/stacktrace.h>
 #include <linux/stackdepot.h>
+#include <linux/seq_file.h>
 
 #define REF_TRACKER_STACK_ENTRIES 16
 #define STACK_BUF_SIZE 1024
@@ -68,6 +69,7 @@ struct ostream {
 	void __ostream_printf (*func)(struct ostream *stream, char *fmt, ...);
 	char *prefix;
 	char *buf;
+	struct seq_file *seq;
 	int size, used;
 };
 
@@ -91,6 +93,15 @@ static void __ostream_printf pr_ostream_buf(struct ostream *stream, char *fmt, .
 	stream->used += min(ret, len);
 }
 
+static void __ostream_printf pr_ostream_seq(struct ostream *stream, char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	seq_vprintf(stream->seq, fmt, args);
+	va_end(args);
+}
+
 #define pr_ostream(stream, fmt, args...) \
 ({ \
 	struct ostream *_s = (stream); \
@@ -300,6 +311,21 @@ EXPORT_SYMBOL_GPL(ref_tracker_free);
 #ifdef CONFIG_DEBUG_FS
 #include <linux/debugfs.h>
 
+static __maybe_unused int
+ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq)
+{
+	struct ostream os = { .func = pr_ostream_seq,
+			      .prefix = "",
+			      .seq = seq };
+	unsigned long flags;
+
+	spin_lock_irqsave(&dir->lock, flags);
+	__ref_tracker_dir_pr_ostream(dir, 16, &os);
+	spin_unlock_irqrestore(&dir->lock, flags);
+
+	return os.used;
+}
+
 static int __init ref_tracker_debugfs_init(void)
 {
 	ref_tracker_debug_dir = debugfs_create_dir("ref_tracker", NULL);

-- 
2.49.0

[PATCH v7 06/10] ref_tracker: automatically register a file in debugfs for a ref_tracker_dir

[Jeff Layton]

Currently, there is no convenient way to see the info that the
ref_tracking infrastructure collects. Attempt to create a file in
debugfs when called from ref_tracker_dir_init().

The file is given the name "class@%px", as having the unmodified address
is helpful for debugging. This should be safe since this directory is only
accessible by root

If debugfs file creation fails, a pr_warn will be isssued.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 include/linux/ref_tracker.h | 13 ++++++++
 lib/ref_tracker.c           | 73 +++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index 3968f993db81e95c0d58c81454311841c1b9cd35..17d5924d595ce95bfb5d8ec6d813490499bd89d0 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -20,12 +20,17 @@ struct ref_tracker_dir {
 	struct list_head	list; /* List of active trackers */
 	struct list_head	quarantine; /* List of dead trackers */
 	const char		*class; /* object classname */
+#ifdef CONFIG_DEBUG_FS
+	struct dentry		*dentry;
+#endif
 	char			name[32];
 #endif
 };
 
 #ifdef CONFIG_REF_TRACKER
 
+void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir);
+
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
 					const char *class,
@@ -39,7 +44,11 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 	refcount_set(&dir->untracked, 1);
 	refcount_set(&dir->no_tracker, 1);
 	dir->class = class;
+#ifdef CONFIG_DEBUG_FS
+	dir->dentry = NULL;
+#endif
 	strscpy(dir->name, name, sizeof(dir->name));
+	ref_tracker_dir_debugfs(dir);
 	stack_depot_init();
 }
 
@@ -68,6 +77,10 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 {
 }
 
+static inline void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir)
+{
+}
+
 static inline void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
 {
 }
diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index 66a765cdfc471968fd6434dafc5b654962f20667..723df31321242d6af267986cc56a9d80b6e5ad18 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -31,6 +31,14 @@ struct ref_tracker_dir_stats {
 	} stacks[];
 };
 
+#ifdef CONFIG_DEBUG_FS
+static void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir);
+#else
+static inline void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir)
+{
+}
+#endif
+
 static struct ref_tracker_dir_stats *
 ref_tracker_get_stats(struct ref_tracker_dir *dir, unsigned int limit)
 {
@@ -195,6 +203,7 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
 	bool leak = false;
 
 	dir->dead = true;
+	ref_tracker_debugfs_remove(dir);
 	spin_lock_irqsave(&dir->lock, flags);
 	list_for_each_entry_safe(tracker, n, &dir->quarantine, head) {
 		list_del(&tracker->head);
@@ -311,8 +320,7 @@ EXPORT_SYMBOL_GPL(ref_tracker_free);
 #ifdef CONFIG_DEBUG_FS
 #include <linux/debugfs.h>
 
-static __maybe_unused int
-ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq)
+static int ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq)
 {
 	struct ostream os = { .func = pr_ostream_seq,
 			      .prefix = "",
@@ -326,6 +334,67 @@ ref_tracker_dir_seq_print(struct ref_tracker_dir *dir, struct seq_file *seq)
 	return os.used;
 }
 
+static int ref_tracker_debugfs_show(struct seq_file *f, void *v)
+{
+	struct ref_tracker_dir *dir = f->private;
+
+	return ref_tracker_dir_seq_print(dir, f);
+}
+
+static int ref_tracker_debugfs_open(struct inode *inode, struct file *filp)
+{
+	struct ref_tracker_dir *dir = inode->i_private;
+
+	return single_open(filp, ref_tracker_debugfs_show, dir);
+}
+
+static const struct file_operations ref_tracker_debugfs_fops = {
+	.owner		= THIS_MODULE,
+	.open		= ref_tracker_debugfs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+/**
+ * ref_tracker_dir_debugfs - create debugfs file for ref_tracker_dir
+ * @dir: ref_tracker_dir to be associated with debugfs file
+ *
+ * In most cases, a debugfs file will be created automatically for every
+ * ref_tracker_dir. If the object was created before debugfs is brought up
+ * then that may fail. In those cases, it is safe to call this at a later
+ * time to create the file.
+ */
+void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir)
+{
+	char name[NAME_MAX + 1];
+	int ret;
+
+	/* No-op if already created */
+	if (!IS_ERR_OR_NULL(dir->dentry))
+		return;
+
+	ret = snprintf(name, sizeof(name), "%s@%px", dir->class, dir);
+	name[sizeof(name) - 1] = '\0';
+
+	if (ret < sizeof(name))
+		dir->dentry = debugfs_create_file(name, S_IFREG | 0400,
+						  ref_tracker_debug_dir, dir,
+						  &ref_tracker_debugfs_fops);
+	else
+		dir->dentry = ERR_PTR(-ENAMETOOLONG);
+
+	if (IS_ERR(dir->dentry))
+		pr_warn("ref_tracker: unable to create debugfs file for %s: %pe\n",
+			name, dir->dentry);
+}
+EXPORT_SYMBOL(ref_tracker_dir_debugfs);
+
+static void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir)
+{
+	debugfs_remove(dir->dentry);
+}
+
 static int __init ref_tracker_debugfs_init(void)
 {
 	ref_tracker_debug_dir = debugfs_create_dir("ref_tracker", NULL);

-- 
2.49.0

[PATCH v7 07/10] ref_tracker: add a way to create a symlink to the ref_tracker_dir debugfs file

[Jeff Layton]

Add the ability for a subsystem to add a user-friendly symlink that
points to a ref_tracker_dir's debugfs file.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 include/linux/ref_tracker.h | 11 +++++++++++
 lib/ref_tracker.c           | 28 ++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index 17d5924d595ce95bfb5d8ec6d813490499bd89d0..b27cb7b3f1be5e16dedceeb0a88e9aa577be5dff 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -22,6 +22,7 @@ struct ref_tracker_dir {
 	const char		*class; /* object classname */
 #ifdef CONFIG_DEBUG_FS
 	struct dentry		*dentry;
+	struct dentry		*symlink;
 #endif
 	char			name[32];
 #endif
@@ -30,6 +31,7 @@ struct ref_tracker_dir {
 #ifdef CONFIG_REF_TRACKER
 
 void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir);
+void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...);
 
 static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 					unsigned int quarantine_count,
@@ -46,6 +48,7 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 	dir->class = class;
 #ifdef CONFIG_DEBUG_FS
 	dir->dentry = NULL;
+	dir->symlink = NULL;
 #endif
 	strscpy(dir->name, name, sizeof(dir->name));
 	ref_tracker_dir_debugfs(dir);
@@ -81,6 +84,10 @@ static inline void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir)
 {
 }
 
+static inline void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...)
+{
+}
+
 static inline void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
 {
 }
@@ -114,6 +121,10 @@ static inline int ref_tracker_free(struct ref_tracker_dir *dir,
 	return 0;
 }
 
+static inline __ostream_printf
+void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...)
+{
+}
 #endif
 
 #endif /* _LINUX_REF_TRACKER_H */
diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index 723df31321242d6af267986cc56a9d80b6e5ad18..d59ef7200dd4f97f247ddd989beb5757b8afd519 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -390,8 +390,36 @@ void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir)
 }
 EXPORT_SYMBOL(ref_tracker_dir_debugfs);
 
+void __ostream_printf ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...)
+{
+	char name[NAME_MAX + 1];
+	va_list args;
+	int ret;
+
+	/* Already created, or dentry doesn't exist? Do nothing */
+	if (!IS_ERR_OR_NULL(dir->symlink) || IS_ERR_OR_NULL(dir->dentry))
+		return;
+
+	va_start(args, fmt);
+	ret = vsnprintf(name, sizeof(name), fmt, args);
+	va_end(args);
+	name[sizeof(name) - 1] = '\0';
+
+	if (ret < sizeof(name))
+		dir->symlink = debugfs_create_symlink(name, ref_tracker_debug_dir,
+						      dir->dentry->d_name.name);
+	else
+		dir->symlink = ERR_PTR(-ENAMETOOLONG);
+
+	if (IS_ERR(dir->symlink))
+		pr_warn("ref_tracker: unable to create debugfs symlink for %s: %pe\n",
+			name, dir->symlink);
+}
+EXPORT_SYMBOL(ref_tracker_dir_symlink);
+
 static void ref_tracker_debugfs_remove(struct ref_tracker_dir *dir)
 {
+	debugfs_remove(dir->symlink);
 	debugfs_remove(dir->dentry);
 }
 

-- 
2.49.0

[PATCH v7 08/10] net: add symlinks to ref_tracker_dir for netns

[Jeff Layton]

After assigning the inode number to the namespace, use it to create a
unique name for each netns refcount tracker with the ns.inum and
net_cookie values in it, and register a symlink to the debugfs file for
it.

init_net is registered before the ref_tracker dir is created, so add a
late_initcall() to register its files and symlinks.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 net/core/net_namespace.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 008de9675ea98fa8c18628b2f1c3aee7f3ebc9c6..1c5e0289f0f0b37c61852d95d4e11a8c12a868f3 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -763,12 +763,40 @@ struct net *get_net_ns_by_pid(pid_t pid)
 }
 EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
 
+#ifdef CONFIG_NET_NS_REFCNT_TRACKER
+static void net_ns_net_debugfs(struct net *net)
+{
+	ref_tracker_dir_symlink(&net->refcnt_tracker, "netns--%lx-%u-refcnt",
+				net->net_cookie, net->ns.inum);
+	ref_tracker_dir_symlink(&net->notrefcnt_tracker, "netns-%lx-%u-notrefcnt",
+				net->net_cookie, net->ns.inum);
+}
+
+static int __init init_net_debugfs(void)
+{
+	ref_tracker_dir_debugfs(&init_net.refcnt_tracker);
+	ref_tracker_dir_debugfs(&init_net.notrefcnt_tracker);
+	net_ns_net_debugfs(&init_net);
+	return 0;
+}
+late_initcall(init_net_debugfs);
+#else
+static void net_ns_net_debugfs(struct net *net)
+{
+}
+#endif
+
 static __net_init int net_ns_net_init(struct net *net)
 {
+	int ret;
+
 #ifdef CONFIG_NET_NS
 	net->ns.ops = &netns_operations;
 #endif
-	return ns_alloc_inum(&net->ns);
+	ret = ns_alloc_inum(&net->ns);
+	if (!ret)
+		net_ns_net_debugfs(net);
+	return ret;
 }
 
 static __net_exit void net_ns_net_exit(struct net *net)

-- 
2.49.0

[PATCH v7 09/10] i915: add ref_tracker_dir symlinks for each tracker

[Jeff Layton]

Now that there is the ability to create a symlink for each tracker, do
so for the i915 entries.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 drivers/gpu/drm/i915/intel_runtime_pm.c | 1 +
 drivers/gpu/drm/i915/intel_wakeref.c    | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 3fdab3b44c08cea16ac2f73aafc2bea2ffbb19e7..94315e952ead9be276298fb2a0200d102005a0c1 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -61,6 +61,7 @@ static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 {
 	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT,
 			     "intel_runtime_pm", dev_name(rpm->kdev));
+	ref_tracker_dir_symlink(&rpm->debug, "intel_runtime_pm-%s", dev_name(rpm->kdev));
 }
 
 static intel_wakeref_t
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index 5269e64c58a49884f5d712557546272bfdeb8417..2e0498b3fa7947f994de1339d4d2bed93de1a795 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -115,6 +115,7 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
 	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, "intel_wakeref", name);
+	ref_tracker_dir_symlink(&wf->debug, "intel_wakeref-%s", name);
 #endif
 }
 

-- 
2.49.0

[PATCH v7 10/10] ref_tracker: eliminate the ref_tracker_dir name field

[Jeff Layton]

Now that we have dentries and the ability to create meaningful symlinks
to them, don't keep a name string in each tracker. Switch the output
format to print "class@address", and drop the name field.

Also, add a kerneldoc header for ref_tracker_dir_init().

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 drivers/gpu/drm/display/drm_dp_tunnel.c |  2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +-
 drivers/gpu/drm/i915/intel_wakeref.c    |  2 +-
 include/linux/ref_tracker.h             | 20 ++++++++++++++------
 lib/ref_tracker.c                       |  6 +++---
 lib/test_ref_tracker.c                  |  2 +-
 net/core/dev.c                          |  2 +-
 net/core/net_namespace.c                |  4 ++--
 8 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_tunnel.c b/drivers/gpu/drm/display/drm_dp_tunnel.c
index f2a8ef6abf34d89a642d7c7708c41e5b1dc9dece..f8d1f9c60e86c5a7b1866e1c9f6425e99d4ca9c6 100644
--- a/drivers/gpu/drm/display/drm_dp_tunnel.c
+++ b/drivers/gpu/drm/display/drm_dp_tunnel.c
@@ -1920,7 +1920,7 @@ drm_dp_tunnel_mgr_create(struct drm_device *dev, int max_group_count)
 	}
 
 #ifdef CONFIG_DRM_DISPLAY_DP_TUNNEL_STATE_DEBUG
-	ref_tracker_dir_init(&mgr->ref_tracker, 16, "drm_dptun", "dptun");
+	ref_tracker_dir_init(&mgr->ref_tracker, 16, "drm_dptun");
 #endif
 
 	for (i = 0; i < max_group_count; i++) {
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 94315e952ead9be276298fb2a0200d102005a0c1..d560f94af7a86f1fc139204a4e901eaea22c6ef1 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -60,7 +60,7 @@ static struct drm_i915_private *rpm_to_i915(struct intel_runtime_pm *rpm)
 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 {
 	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT,
-			     "intel_runtime_pm", dev_name(rpm->kdev));
+			     "intel_runtime_pm");
 	ref_tracker_dir_symlink(&rpm->debug, "intel_runtime_pm-%s", dev_name(rpm->kdev));
 }
 
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index 2e0498b3fa7947f994de1339d4d2bed93de1a795..bbd5171ce0a22435e540f10821f2a0dad59c1d2f 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -114,7 +114,7 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
 			 "wakeref.work", &key->work, 0);
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
-	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, "intel_wakeref", name);
+	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, "intel_wakeref");
 	ref_tracker_dir_symlink(&wf->debug, "intel_wakeref-%s", name);
 #endif
 }
diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index b27cb7b3f1be5e16dedceeb0a88e9aa577be5dff..87c655ffdd77a0e5f080c32633853efea866aca3 100644
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -24,7 +24,6 @@ struct ref_tracker_dir {
 	struct dentry		*dentry;
 	struct dentry		*symlink;
 #endif
-	char			name[32];
 #endif
 };
 
@@ -33,10 +32,21 @@ struct ref_tracker_dir {
 void ref_tracker_dir_debugfs(struct ref_tracker_dir *dir);
 void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...);
 
+/**
+ * ref_tracker_dir_init - initialize a ref_tracker dir
+ * @dir: ref_tracker_dir to be initialized
+ * @quarantime_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 *class,
-					const char *name)
+					const char *class)
 {
 	INIT_LIST_HEAD(&dir->list);
 	INIT_LIST_HEAD(&dir->quarantine);
@@ -50,7 +60,6 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 	dir->dentry = NULL;
 	dir->symlink = NULL;
 #endif
-	strscpy(dir->name, name, sizeof(dir->name));
 	ref_tracker_dir_debugfs(dir);
 	stack_depot_init();
 }
@@ -75,8 +84,7 @@ 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 *class,
-					const char *name)
+					const char *class)
 {
 }
 
diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index d59ef7200dd4f97f247ddd989beb5757b8afd519..6c28d26c2e3e37a7ccd39893a29390149283d588 100644
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -134,7 +134,7 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 	stats = ref_tracker_get_stats(dir, display_limit);
 	if (IS_ERR(stats)) {
 		pr_ostream(s, "%s%s@%p: couldn't get stats, error %pe\n",
-			   s->prefix, dir->name, dir, stats);
+			   s->prefix, dir->class, dir, stats);
 		return;
 	}
 
@@ -145,14 +145,14 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
 		if (sbuf && !stack_depot_snprint(stack, sbuf, STACK_BUF_SIZE, 4))
 			sbuf[0] = 0;
 		pr_ostream(s, "%s%s@%p has %d/%d users at\n%s\n", s->prefix,
-			   dir->name, dir, stats->stacks[i].count,
+			   dir->class, dir, stats->stacks[i].count,
 			   stats->total, sbuf);
 		skipped -= stats->stacks[i].count;
 	}
 
 	if (skipped)
 		pr_ostream(s, "%s%s@%p skipped reports about %d/%d users.\n",
-			   s->prefix, dir->name, dir, skipped, stats->total);
+			   s->prefix, dir->class, dir, skipped, stats->total);
 
 	kfree(sbuf);
 
diff --git a/lib/test_ref_tracker.c b/lib/test_ref_tracker.c
index d263502a4c1db248f64a66a468e96c8e4cffab25..b983ceb12afcb84ad60360a1e6fec0072e78ef79 100644
--- a/lib/test_ref_tracker.c
+++ b/lib/test_ref_tracker.c
@@ -64,7 +64,7 @@ static int __init test_ref_tracker_init(void)
 {
 	int i;
 
-	ref_tracker_dir_init(&ref_dir, 100, "selftest", "selftest");
+	ref_tracker_dir_init(&ref_dir, 100, "selftest");
 
 	timer_setup(&test_ref_tracker_timer, test_ref_tracker_timer_func, 0);
 	mod_timer(&test_ref_tracker_timer, jiffies + 1);
diff --git a/net/core/dev.c b/net/core/dev.c
index 380d07bec15a1f62ed27c31a6e211e74f3a5561d..00776cba0276554066c94a6fc86f5ed4df430cfa 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11620,7 +11620,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 
 	dev->priv_len = sizeof_priv;
 
-	ref_tracker_dir_init(&dev->refcnt_tracker, 128, "netdev", name);
+	ref_tracker_dir_init(&dev->refcnt_tracker, 128, "netdev");
 #ifdef CONFIG_PCPU_DEV_REFCNT
 	dev->pcpu_refcnt = alloc_percpu(int);
 	if (!dev->pcpu_refcnt)
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 1c5e0289f0f0b37c61852d95d4e11a8c12a868f3..5b06a0bf88e62c19f6f610eca3a4c4750ff4a2ea 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -324,8 +324,8 @@ static __net_init void preinit_net(struct net *net, struct user_namespace *user_
 {
 	refcount_set(&net->passive, 1);
 	refcount_set(&net->ns.count, 1);
-	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net_refcnt", "net_refcnt");
-	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net_notrefcnt", "net_notrefcnt");
+	ref_tracker_dir_init(&net->refcnt_tracker, 128, "net_refcnt");
+	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "net_notrefcnt");
 
 	get_random_bytes(&net->hash_mix, sizeof(u32));
 	net->dev_base_seq = 1;

-- 
2.49.0

Re: [PATCH v7 09/10] i915: add ref_tracker_dir symlinks for each tracker

[Jani Nikula]

On Mon, 05 May 2025, Jeff Layton <jlayton@kernel.org> wrote:
> Now that there is the ability to create a symlink for each tracker, do
> so for the i915 entries.

I haven't tried this, but

Acked-by: Jani Nikula <jani.nikula@intel.com>


>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 1 +
>  drivers/gpu/drm/i915/intel_wakeref.c    | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 3fdab3b44c08cea16ac2f73aafc2bea2ffbb19e7..94315e952ead9be276298fb2a0200d102005a0c1 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -61,6 +61,7 @@ static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
>  {
>  	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT,
>  			     "intel_runtime_pm", dev_name(rpm->kdev));
> +	ref_tracker_dir_symlink(&rpm->debug, "intel_runtime_pm-%s", dev_name(rpm->kdev));
>  }
>  
>  static intel_wakeref_t
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
> index 5269e64c58a49884f5d712557546272bfdeb8417..2e0498b3fa7947f994de1339d4d2bed93de1a795 100644
> --- a/drivers/gpu/drm/i915/intel_wakeref.c
> +++ b/drivers/gpu/drm/i915/intel_wakeref.c
> @@ -115,6 +115,7 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
>  
>  #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
>  	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, "intel_wakeref", name);
> +	ref_tracker_dir_symlink(&wf->debug, "intel_wakeref-%s", name);
>  #endif
>  }

-- 
Jani Nikula, Intel