diff --git a/fsdev/9p-marshal.h b/fsdev/9p-marshal.h
index e91b24e..140db6d 100644
--- a/fsdev/9p-marshal.h
+++ b/fsdev/9p-marshal.h
@@ -1,5 +1,5 @@
-#ifndef _QEMU_9P_MARSHAL_H
-#define _QEMU_9P_MARSHAL_H
+#ifndef QEMU_9P_MARSHAL_H
+#define QEMU_9P_MARSHAL_H
 
 typedef struct V9fsString
 {