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>

2 files changed, 32 insertions, 4 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index df1678b1fe24..7ee808eb068e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -11756,7 +11756,7 @@ 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");
 #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 ae54f26709ca..d0f607507ee8 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");
-	ref_tracker_dir_init(&net->notrefcnt_tracker, 128, "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;
@@ -791,12 +791,40 @@ 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-%llx-%u-refcnt",
+				net->net_cookie, net->ns.inum);
+	ref_tracker_dir_symlink(&net->notrefcnt_tracker, "netns-%llx-%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)