diff --git a/[refs] b/[refs]
index cd98ab0b1bf0..eb98f9dca485 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 63b9871f6ee2607f3b44e0044e145574b3f08619
+refs/heads/master: 6d0742426c9adc7465ef5c62a99a1d3e9696ea19
diff --git a/trunk/arch/um/drivers/ubd_kern.c b/trunk/arch/um/drivers/ubd_kern.c
index 5e45e39a8a8d..44ad1607be2d 100644
--- a/trunk/arch/um/drivers/ubd_kern.c
+++ b/trunk/arch/um/drivers/ubd_kern.c
@@ -1178,8 +1178,8 @@ static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask,
 	 * by one word.  Thanks to Lynn Kerby for the fix and James McMechan
 	 * for the original diagnosis.
 	 */
-	if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) /
-			   sizeof(unsigned long) - 1))
+	if (*cow_offset == (DIV_ROUND_UP(bitmap_len,
+					 sizeof(unsigned long)) - 1))
 		(*cow_offset)--;
 
 	bitmap_words[0] = bitmap[*cow_offset];