[PATCH v3 11/13] mm/writeback: add folio_mark_dirty_lock()

[Joanne Koong <joannelkoong@gmail.com>]

Add a new convenience helper folio_mark_dirty_lock() that grabs the
folio lock before calling folio_mark_dirty().

Refactor set_page_dirty_lock() to directly use folio_mark_dirty_lock().

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 include/linux/mm.h  |  1 +
 mm/folio-compat.c   |  6 ++++++
 mm/page-writeback.c | 22 +++++++++++-----------
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ecf63d2b0582..446d7096c48f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2539,6 +2539,7 @@ struct kvec;
 struct page *get_dump_page(unsigned long addr);
 
 bool folio_mark_dirty(struct folio *folio);
+bool folio_mark_dirty_lock(struct folio *folio);
 bool set_page_dirty(struct page *page);
 int set_page_dirty_lock(struct page *page);
 
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 80746182e9e8..1d1832e2a599 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -52,6 +52,12 @@ bool set_page_dirty(struct page *page)
 }
 EXPORT_SYMBOL(set_page_dirty);
 
+int set_page_dirty_lock(struct page *page)
+{
+	return folio_mark_dirty_lock(page_folio(page));
+}
+EXPORT_SYMBOL(set_page_dirty_lock);
+
 bool clear_page_dirty_for_io(struct page *page)
 {
 	return folio_clear_dirty_for_io(page_folio(page));
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index fcd4c1439cb9..db00a66d8b84 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2914,25 +2914,25 @@ bool folio_mark_dirty(struct folio *folio)
 EXPORT_SYMBOL(folio_mark_dirty);
 
 /*
- * set_page_dirty() is racy if the caller has no reference against
- * page->mapping->host, and if the page is unlocked.  This is because another
- * CPU could truncate the page off the mapping and then free the mapping.
+ * folio_mark_dirty() is racy if the caller has no reference against
+ * folio->mapping->host, and if the folio is unlocked.  This is because another
+ * CPU could truncate the folio off the mapping and then free the mapping.
  *
- * Usually, the page _is_ locked, or the caller is a user-space process which
+ * Usually, the folio _is_ locked, or the caller is a user-space process which
  * holds a reference on the inode by having an open file.
  *
- * In other cases, the page should be locked before running set_page_dirty().
+ * In other cases, the folio should be locked before running folio_mark_dirty().
  */
-int set_page_dirty_lock(struct page *page)
+bool folio_mark_dirty_lock(struct folio *folio)
 {
-	int ret;
+	bool ret;
 
-	lock_page(page);
-	ret = set_page_dirty(page);
-	unlock_page(page);
+	folio_lock(folio);
+	ret = folio_mark_dirty(folio);
+	folio_unlock(folio);
 	return ret;
 }
-EXPORT_SYMBOL(set_page_dirty_lock);
+EXPORT_SYMBOL(folio_mark_dirty_lock);
 
 /*
  * This cancels just the dirty bit on the kernel page itself, it does NOT
-- 
2.43.5