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

[Zack Rusin]

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 <za...@vmware.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Thomas Hellström (Intel) <thomas...@shipmail.org>
Cc: linux...@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