mm/writeback: Add __folio_end_writeback()

test_clear_page_writeback() is actually an mm-internal function, although
it's named as if it's a pagecache function.  Move it to mm/internal.h,
rename it to __folio_end_writeback() and change the return type to bool.

The conversion from page to folio is mostly about accounting the number
of pages being written back, although it does eliminate a couple of
calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 5368a4dcc35e..5cb18399a1b6 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1590,7 +1590,7 @@ void folio_end_writeback(struct folio *folio)
 	 * reused before the folio_wake().
 	 */
 	folio_get(folio);
-	if (!test_clear_page_writeback(&folio->page))
+	if (!__folio_end_writeback(folio))
 		BUG();
 
 	smp_mb__after_atomic();