diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3d3848fa6324ee30c8bfa4f39ac867808af84627..8137482abd6e862249fa9b4e8a66fcff6cf22821 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -219,7 +219,7 @@ static inline void task_dirties_fraction(struct task_struct *tsk,
  *
  *   dirty -= (dirty/8) * p_{t}
  */
-void task_dirty_limit(struct task_struct *tsk, long *pdirty)
+static void task_dirty_limit(struct task_struct *tsk, long *pdirty)
 {
 	long numerator, denominator;
 	long dirty = *pdirty;