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/utsname.c b/kernel/utsname.c
index 20697be..c2a2b32 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -42,7 +42,7 @@
 	if (!ns)
 		return ERR_PTR(-ENOMEM);
 
-	err = proc_alloc_inum(&ns->ns.inum);
+	err = ns_alloc_inum(&ns->ns);
 	if (err) {
 		kfree(ns);
 		return ERR_PTR(err);
@@ -84,7 +84,7 @@
 
 	ns = container_of(kref, struct uts_namespace, kref);
 	put_user_ns(ns->user_ns);
-	proc_free_inum(ns->ns.inum);
+	ns_free_inum(&ns->ns);
 	kfree(ns);
 }