From: Anthony G. Basile <blueness@gentoo.org>

For users that emerge without XATTR_PAX support enabled, we still want user.pax.flags
namespace supported on tmpfs so that the PaX markings survive emerge.

diff -Naur a/mm/shmem.c b/mm/shmem.c
--- a/mm/shmem.c	2013-06-11 21:00:18.000000000 -0400
+++ b/mm/shmem.c	2013-06-11 21:08:18.000000000 -0400
@@ -2232,11 +2232,7 @@
 static int shmem_xattr_validate(const char *name)
 {
 	struct { const char *prefix; size_t len; } arr[] = {
-
-#ifdef CONFIG_PAX_XATTR_PAX_FLAGS
 		{ XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN},
-#endif
-
 		{ XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN },
 		{ XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN }
 	};
@@ -2292,14 +2288,12 @@
 	if (err)
 		return err;
 
-#ifdef CONFIG_PAX_XATTR_PAX_FLAGS
 	if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
 		if (strcmp(name, XATTR_NAME_PAX_FLAGS))
 			return -EOPNOTSUPP;
 		if (size > 8)
 			return -EINVAL;
 	}
-#endif
 
 	return simple_xattr_set(&info->xattrs, name, value, size, flags);
 }