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-rw-r--r--include/linux/mm.h8
-rw-r--r--mm/page-writeback.c4
2 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 703599fa8288..c7b1d617dff6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1440,7 +1440,13 @@ 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);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 83c746577aea..436714917e03 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2608,7 +2608,7 @@ 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);
@@ -2629,7 +2629,7 @@ 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.