mm/page_io: use a folio in swap_writepage_bdev_sync()

Saves one implicit call to compound_head().

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhangPeng <[email protected]>
Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Nanyong Sun <[email protected]>
Cc: Sidhartha Kumar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: ZhangPeng

mm/page_io.c

@@ -331,6 +331,7 @@ static void swap_writepage_bdev_sync(struct page *page,
 {
 	struct bio_vec bv;
 	struct bio bio;
+	struct folio *folio = page_folio(page);
 
 	bio_init(&bio, sis->bdev, &bv, 1,
 		 REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc));
@@ -340,8 +341,8 @@ static void swap_writepage_bdev_sync(struct page *page,
 	bio_associate_blkg_from_page(&bio, page);
 	count_swpout_vm_event(page);
 
-	set_page_writeback(page);
-	unlock_page(page);
+	folio_start_writeback(folio);
+	folio_unlock(folio);
 
 	submit_bio_wait(&bio);
 	__end_swap_bio_write(&bio);