diff --git a/include/linux/unix_diag.h b/include/linux/unix_diag.h
index b8a2494..b9e2a6a 100644
--- a/include/linux/unix_diag.h
+++ b/include/linux/unix_diag.h
@@ -39,9 +39,11 @@
 	UNIX_DIAG_MEMINFO,
 	UNIX_DIAG_SHUTDOWN,
 
-	UNIX_DIAG_MAX,
+	__UNIX_DIAG_MAX,
 };
 
+#define UNIX_DIAG_MAX (__UNIX_DIAG_MAX - 1)
+
 struct unix_diag_vfs {
 	__u32	udiag_vfs_ino;
 	__u32	udiag_vfs_dev;