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/ipc/namespace.c b/ipc/namespace.c
index 531029a..bcdd7a5 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -26,7 +26,7 @@
 	if (ns == NULL)
 		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);
@@ -35,7 +35,7 @@
 	atomic_set(&ns->count, 1);
 	err = mq_init_ns(ns);
 	if (err) {
-		proc_free_inum(ns->ns.inum);
+		ns_free_inum(&ns->ns);
 		kfree(ns);
 		return ERR_PTR(err);
 	}
@@ -119,7 +119,7 @@
 	 */
 	ipcns_notify(IPCNS_REMOVED);
 	put_user_ns(ns->user_ns);
-	proc_free_inum(ns->ns.inum);
+	ns_free_inum(&ns->ns);
 	kfree(ns);
 }