[PATCH] mm/mapping_dirty_helpers: Guard hugepage pud's usage

[Zack Rusin <zackr@vmware.com>]

Lets make sure we don't use pud hugepage helpers on architectures
which do not support it. This fixes the code on arm64.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Hellström (Intel) <thomas_os@shipmail.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/mapping_dirty_helpers.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c
index b59054ef2e10..b890854ec761 100644
--- a/mm/mapping_dirty_helpers.c
+++ b/mm/mapping_dirty_helpers.c
@@ -165,10 +165,12 @@ static int wp_clean_pud_entry(pud_t *pud, unsigned long addr, unsigned long end,
 		return 0;
 	}
 
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 	/* Huge pud */
 	walk->action = ACTION_CONTINUE;
 	if (pud_trans_huge(pudval) || pud_devmap(pudval))
 		WARN_ON(pud_write(pudval) || pud_dirty(pudval));
+#endif
 
 	return 0;
 }
-- 
2.27.0