new helpers: ns_alloc_inum/ns_free_inum

take struct ns_common *, for now simply wrappers around proc_{alloc,free}_inum()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 79aabce..5aa9158 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -105,7 +105,7 @@
 	if (ns->pid_cachep == NULL)
 		goto out_free_map;
 
-	err = proc_alloc_inum(&ns->ns.inum);
+	err = ns_alloc_inum(&ns->ns);
 	if (err)
 		goto out_free_map;
 
@@ -142,7 +142,7 @@
 {
 	int i;
 
-	proc_free_inum(ns->ns.inum);
+	ns_free_inum(&ns->ns);
 	for (i = 0; i < PIDMAP_ENTRIES; i++)
 		kfree(ns->pidmap[i].page);
 	put_user_ns(ns->user_ns);