mm: pass a folio to swap_readpage_bdev_sync()

Make it plain that this takes the head page (which before this point
was just an assumption, but is now enforced by the compiler).

Link: https://lkml.kernel.org/r/20231213215842.671461-8-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_io.c

@@ -454,15 +454,15 @@ static void swap_readpage_fs(struct folio *folio, struct swap_iocb **plug)
 		*plug = sio;
 }
 
-static void swap_readpage_bdev_sync(struct page *page,
+static void swap_readpage_bdev_sync(struct folio *folio,
 		struct swap_info_struct *sis)
 {
 	struct bio_vec bv;
 	struct bio bio;
 
 	bio_init(&bio, sis->bdev, &bv, 1, REQ_OP_READ);
-	bio.bi_iter.bi_sector = swap_page_sector(page);
-	__bio_add_page(&bio, page, thp_size(page), 0);
+	bio.bi_iter.bi_sector = swap_page_sector(&folio->page);
+	bio_add_folio_nofail(&bio, folio, folio_size(folio), 0);
 	/*
 	 * Keep this task valid during swap readpage because the oom killer may
 	 * attempt to access it in the page fault retry time check.
@@ -516,7 +516,7 @@ void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
 	} else if (data_race(sis->flags & SWP_FS_OPS)) {
 		swap_readpage_fs(folio, plug);
 	} else if (synchronous || (sis->flags & SWP_SYNCHRONOUS_IO)) {
-		swap_readpage_bdev_sync(page, sis);
+		swap_readpage_bdev_sync(folio, sis);
 	} else {
 		swap_readpage_bdev_async(page, sis);
 	}