Add folio_end_writeback_pages() which takes in the number of pages
written back.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 include/linux/pagemap.h |  1 +
 mm/filemap.c            | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 12a12dae727d..362900730247 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1221,6 +1221,7 @@ void folio_wait_writeback(struct folio *folio);
 int folio_wait_writeback_killable(struct folio *folio);
 void end_page_writeback(struct page *page);
 void folio_end_writeback(struct folio *folio);
+void folio_end_writeback_pages(struct folio *folio, long nr_pages);
 void folio_wait_stable(struct folio *folio);
 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);
 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
diff --git a/mm/filemap.c b/mm/filemap.c
index cbfb0f085eb6..6d50afaff930 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1627,14 +1627,15 @@ static void filemap_end_dropbehind_write(struct folio *folio)
 }
 
 /**
- * folio_end_writeback - End writeback against a folio.
+ * folio_end_writeback_pages - End writeback against a folio.
  * @folio: The folio.
+ * @nr_pages: The number of pages written back.
  *
  * The folio must actually be under writeback.
  *
  * Context: May be called from process or interrupt context.
  */
-void folio_end_writeback(struct folio *folio)
+void folio_end_writeback_pages(struct folio *folio, long nr_pages)
 {
 	VM_BUG_ON_FOLIO(!folio_test_writeback(folio), folio);
 
@@ -1657,13 +1658,18 @@ void folio_end_writeback(struct folio *folio)
 	 * reused before the folio_wake_bit().
 	 */
 	folio_get(folio);
-	if (__folio_end_writeback(folio, folio_nr_pages(folio)))
+	if (__folio_end_writeback(folio, nr_pages))
 		folio_wake_bit(folio, PG_writeback);
 
 	filemap_end_dropbehind_write(folio);
 	acct_reclaim_writeback(folio);
 	folio_put(folio);
 }
+
+void folio_end_writeback(struct folio *folio)
+{
+	folio_end_writeback_pages(folio, folio_nr_pages(folio));
+}
 EXPORT_SYMBOL(folio_end_writeback);
 
 /**
-- 
2.47.3