From b36c823b9a4be5b0c8e38c3fd60cade7d41c216c Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner@kernel.org>
Date: Fri, 12 Sep 2025 13:52:46 +0200
Subject: time: support ns lookup

Support the generic ns lookup infrastructure to support file handles for
namespaces.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 kernel/time/namespace.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'kernel/time/namespace.c')

diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index 0be93d8f2896..408f60d0a3b6 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -12,6 +12,7 @@
 #include <linux/seq_file.h>
 #include <linux/proc_ns.h>
 #include <linux/export.h>
+#include <linux/nstree.h>
 #include <linux/time.h>
 #include <linux/slab.h>
 #include <linux/cred.h>
@@ -104,6 +105,7 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns,
 	ns->user_ns = get_user_ns(user_ns);
 	ns->offsets = old_ns->offsets;
 	ns->frozen_offsets = false;
+	ns_tree_add(ns);
 	return ns;
 
 fail_free_page:
@@ -250,11 +252,13 @@ out:
 
 void free_time_ns(struct time_namespace *ns)
 {
+	ns_tree_remove(ns);
 	dec_time_namespaces(ns->ucounts);
 	put_user_ns(ns->user_ns);
 	ns_free_inum(&ns->ns);
 	__free_page(ns->vvar_page);
-	kfree(ns);
+	/* Concurrent nstree traversal depends on a grace period. */
+	kfree_rcu(ns, ns.ns_rcu);
 }
 
 static struct time_namespace *to_time_ns(struct ns_common *ns)
@@ -487,3 +491,8 @@ struct time_namespace init_time_ns = {
 	.ns.ops		= &timens_operations,
 	.frozen_offsets	= true,
 };
+
+void __init time_ns_init(void)
+{
+	ns_tree_add(&init_time_ns);
+}
-- 
cgit