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	2016-04-29 19:56:25.306101147 -0400
+++ b/mm/shmem.c	2016-04-29 19:59:44.126104490 -0400
@@ -2657,7 +2657,6 @@
 	return simple_xattr_set(&info->xattrs, name, value, size, flags);
 }
 
-#ifdef CONFIG_PAX_XATTR_PAX_FLAGS
 static int shmem_user_xattr_handler_set(const struct xattr_handler *handler,
 					struct dentry *dentry, struct inode *inode,
 					const char *name, const void *value,
@@ -2673,7 +2672,6 @@
 	name = xattr_full_name(handler, name);
 	return simple_xattr_set(&info->xattrs, name, value, size, flags);
 }
-#endif
 
 static const struct xattr_handler shmem_security_xattr_handler = {
 	.prefix = XATTR_SECURITY_PREFIX,
@@ -2687,13 +2685,11 @@
 	.set = shmem_xattr_handler_set,
 };
 
-#ifdef CONFIG_PAX_XATTR_PAX_FLAGS
 static const struct xattr_handler shmem_user_xattr_handler = {
 	.prefix = XATTR_USER_PREFIX,
 	.get = shmem_xattr_handler_get,
 	.set = shmem_user_xattr_handler_set,
 };
-#endif
 
 static const struct xattr_handler *shmem_xattr_handlers[] = {
 #ifdef CONFIG_TMPFS_POSIX_ACL
@@ -2703,9 +2699,7 @@
 	&shmem_security_xattr_handler,
 	&shmem_trusted_xattr_handler,
 
-#ifdef CONFIG_PAX_XATTR_PAX_FLAGS
 	&shmem_user_xattr_handler,
-#endif
 
 	NULL
 };