xattr: guard against simultaneous glibc header inclusion

If the glibc xattr.h header is included after the uapi header,
compilation fails due to an enum re-using a #define from the uapi
header.

Protect against this by guarding the define and enum inclusions against
each other.

(See https://lists.debian.org/debian-glibc/2014/03/msg00029.html
and https://sourceware.org/glibc/wiki/Synchronizing_Headers
for more information.)

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Allan McRae <allan@archlinux.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index 40bbc04b6f81..c38355c1f3c9 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -7,11 +7,18 @@
   Copyright (c) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.
   Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
 */
+
+#include <linux/libc-compat.h>
+
 #ifndef _UAPI_LINUX_XATTR_H
 #define _UAPI_LINUX_XATTR_H
 
+#ifdef __UAPI_DEF_XATTR
+#define __USE_KERNEL_XATTR_DEFS
+
 #define XATTR_CREATE    0x1     /* set value, fail if attr already exists */
 #define XATTR_REPLACE   0x2     /* set value, fail if attr does not exist */
+#endif
 
 /* Namespaces */
 #define XATTR_OS2_PREFIX "os2."