1 files changed, 1 insertions, 1 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 742c40583159..efe68148f621 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -696,7 +696,7 @@ static unsigned long bdi_position_ratio(struct backing_dev_info *bdi,
          *     => fast response on large errors; small oscillation near setpoint
          */
         setpoint = (freerun + limit) / 2;
-        x = div_s64((setpoint - dirty) << RATELIMIT_CALC_SHIFT,
+        x = div_s64(((s64)setpoint - (s64)dirty) << RATELIMIT_CALC_SHIFT,
                     limit - setpoint + 1);
         pos_ratio = x;
         pos_ratio = pos_ratio * x >> RATELIMIT_CALC_SHIFT;