diff --git a/fs/btrfs/math.h b/fs/btrfs/math.h
index b7816ce..1b10a3c 100644
--- a/fs/btrfs/math.h
+++ b/fs/btrfs/math.h
@@ -28,8 +28,7 @@
 	if (factor == 10)
 		return num;
 	num *= factor;
-	do_div(num, 10);
-	return num;
+	return div_u64(num, 10);
 }
 
 static inline u64 div_factor_fine(u64 num, int factor)
@@ -37,8 +36,7 @@
 	if (factor == 100)
 		return num;
 	num *= factor;
-	do_div(num, 100);
-	return num;
+	return div_u64(num, 100);
 }
 
 #endif