[PATCH 17/23] pid: Add pid namespaces into ns_idr

[Kirill Tkhai]

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

Note, that we already wait RCU grace period before
pid namespace's memory is freed.

Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
---
 kernel/pid_namespace.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index da8490390f51..06398a7c4c59 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -109,8 +109,13 @@ static struct pid_namespace *create_pid_namespace(struct 
user_namespace *user_ns
        ns->ucounts = ucounts;
        ns->pid_allocated = PIDNS_ADDING;
 
+       if (ns_idr_register(&ns->ns) < 0)
+               goto out_free_inum;
+
        return ns;
 
+out_free_inum:
+       ns_free_inum(&ns->ns);
 out_free_idr:
        idr_destroy(&ns->idr);
        kmem_cache_free(pid_ns_cachep, ns);
@@ -132,6 +137,7 @@ static void delayed_free_pidns(struct rcu_head *p)
 
 static void destroy_pid_namespace(struct pid_namespace *ns)
 {
+       ns_idr_unregister(&ns->ns);
        ns_free_inum(&ns->ns);
 
        idr_destroy(&ns->idr);
@@ -466,6 +472,7 @@ static __init int pid_namespaces_init(void)
 #ifdef CONFIG_CHECKPOINT_RESTORE
        register_sysctl_paths(kern_path, pid_ns_ctl_table);
 #endif
+       WARN_ON(ns_idr_register(&init_pid_ns.ns) < 0);
        return 0;
 }