@@ -1430,7 +1430,13 @@ void account_page_cleaned(struct page *page, struct address_space *mapping,
struct bdi_writeback *wb);
int set_page_dirty(struct page *page);
int set_page_dirty_lock(struct page *page);
-void cancel_dirty_page(struct page *page);
+void __cancel_dirty_page(struct page *page);
+static inline void cancel_dirty_page(struct page *page)
+{
+ /* Avoid atomic ops, locking, etc. when not actually needed. */
+ if (PageDirty(page))
+ __cancel_dirty_page(page);
+}
int clear_page_dirty_for_io(struct page *page);
int get_cmdline(struct task_struct *task, char *buffer, int buflen);
@@ -2623,7 +2623,7 @@ EXPORT_SYMBOL(set_page_dirty_lock);
* page without actually doing it through the VM. Can you say "ext3 is
* horribly ugly"? Thought you could.
*/
-void cancel_dirty_page(struct page *page)
+void __cancel_dirty_page(struct page *page)
{
struct address_space *mapping = page_mapping(page);
@@ -2644,7 +2644,7 @@ void cancel_dirty_page(struct page *page)
ClearPageDirty(page);
}
}
-EXPORT_SYMBOL(cancel_dirty_page);
+EXPORT_SYMBOL(__cancel_dirty_page);
/*
* Clear a page's dirty flag, while caring for dirty memory accounting.