[PATCH v10 9/9] ref_tracker: eliminate the ref_tracker_dir name field
Jeff Layton
jlayton at kernel.org
Tue May 27 17:24:14 UTC 2025
On Tue, 2025-05-27 at 07:33 -0400, Jeff Layton wrote:
> 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 at address", and drop the name field.
>
> Also, add a kerneldoc header for ref_tracker_dir_init().
>
> Signed-off-by: Jeff Layton <jlayton at 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 b9c12b8bf2a3e400b6d8e9d184145834c603b9e1..1205a4432eb4142344fb6eed1cb5ba5b21ec6953 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 3fdab3b44c08cea16ac2f73aafc2bea2ffbb19e7..c12b5d0e16fa363f3caede372e7a2031676aa7b5 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");
> }
>
I got a warning from the intel graphics CI that this was causing these
warnings:
<3> [513.235988] debugfs: File 'intel_runtime_pm at ff110001461f98a8' in directory 'ref_tracker' already present!
<4> [513.236073] ref_tracker: ref_tracker: unable to create debugfs file for intel_runtime_pm at ff110001461f98a8: -EEXIST
<3> [513.242646] debugfs: File 'intel_wakeref at ff1100016ee7d790' in directory 'ref_tracker' already present!
<4> [513.242724] ref_tracker: ref_tracker: unable to create debugfs file for intel_wakeref at ff1100016ee7d790: -EEXIST
I suspect these are existing bugs which are causing these ref_trackers
to be initialized more than once. If there were references taken
between these two initializations, then that could leak memory (or
worse). I think we need to ensure that these ref_trackers are only
initialized once.
I'll see if I can make a patch that does that, but if the i915 devs
want to do fix this up instead, I won't complain.
> static intel_wakeref_t
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
> index 5269e64c58a49884f5d712557546272bfdeb8417..615fb77809291be34d94600fdd4d919461a22720 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");
> #endif
> }
>
> diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
> index ddc5a7b2bd84692bbc1e1ae67674ec2c6857e1ec..5878e7fce712930700054033ff5f21547e75224f 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
> };
>
> @@ -48,10 +47,21 @@ 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 *class,
> - const char *name)
> + const char *class)
> {
> INIT_LIST_HEAD(&dir->list);
> INIT_LIST_HEAD(&dir->quarantine);
> @@ -65,7 +75,6 @@ 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();
> }
> @@ -90,8 +99,7 @@ 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 5e84e5fd78e147a036d4adb511e657da07866a55..5fb384dd919e1f1ad632eaf595b954118bcfddab 100644
> --- a/lib/ref_tracker.c
> +++ b/lib/ref_tracker.c
> @@ -123,7 +123,7 @@ __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;
> }
>
> @@ -134,14 +134,14 @@ __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 bac9d29486556023cd99f5101b96b052acb9ba70..a062912525ee573504a9cc252f71aed22693d24f 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -11713,7 +11713,7 @@ 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 39b01af90d240df48827e5c3159c3e2253e0a44d..c03757e39c8a334d307fa1b5cc8f03ad3a8df0e0 100644
> --- a/net/core/net_namespace.c
> +++ b/net/core/net_namespace.c
> @@ -403,8 +403,8 @@ 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;
--
Jeff Layton <jlayton at kernel.org>
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