[PATCH 23/23] time: Add time namespaces into ns_idr

[Kirill Tkhai]

Now they are exposed in /proc/namespace/ directory.

Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
---
 include/linux/time_namespace.h |    1 +
 kernel/time/namespace.c        |   11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index a51ffc089219..18eb8a9f7d68 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -24,6 +24,7 @@ struct time_namespace {
        struct page             *vvar_page;
        /* If set prevents changing offsets after any task joined namespace. */
        bool                    frozen_offsets;
+       struct rcu_head         rcu;
 } __randomize_layout;
 
 extern struct time_namespace init_time_ns;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index c4c829eb3511..164a057ccbfc 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -107,8 +107,15 @@ 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;
+
+       err = ns_idr_register(&ns->ns);
+       if (err)
+               goto fail_put_userns;
        return ns;
 
+fail_put_userns:
+       put_user_ns(user_ns);
+       ns_free_inum(&ns->ns);
 fail_free_page:
        __free_page(ns->vvar_page);
 fail_free:
@@ -228,11 +235,12 @@ static void timens_set_vvar_page(struct task_struct *task,
 
 void free_time_ns(struct time_namespace *ns)
 {
+       ns_idr_unregister(&ns->ns);
        dec_time_namespaces(ns->ucounts);
        put_user_ns(ns->user_ns);
        ns_free_inum(&ns->ns);
        __free_page(ns->vvar_page);
-       kfree(ns);
+       kfree_rcu(ns, rcu);
 }
 
 static struct time_namespace *to_time_ns(struct ns_common *ns)
@@ -470,6 +478,7 @@ struct time_namespace init_time_ns = {
 
 static int __init time_ns_init(void)
 {
+       WARN_ON(ns_idr_register(&init_time_ns.ns) < 0);
        return 0;
 }
 subsys_initcall(time_ns_init);