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/include/linux/proc_ns.h b/include/linux/proc_ns.h
index f284959..f5780ee 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -71,4 +71,7 @@
 
 #endif /* CONFIG_PROC_FS */
 
+#define ns_alloc_inum(ns) proc_alloc_inum(&(ns)->inum)
+#define ns_free_inum(ns) proc_free_inum((ns)->inum)
+
 #endif /* _LINUX_PROC_NS_H */