diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e0c94301..91d73ef 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -261,14 +261,11 @@
  */
 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
 {
+	const unsigned long available_memory = global_dirtyable_memory();
 	unsigned long background;
 	unsigned long dirty;
-	unsigned long uninitialized_var(available_memory);
 	struct task_struct *tsk;
 
-	if (!vm_dirty_bytes || !dirty_background_bytes)
-		available_memory = global_dirtyable_memory();
-
 	if (vm_dirty_bytes)
 		dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
 	else