ext4: Convert ext4_bio_write_page() to ext4_bio_write_folio()

The only caller now has a folio so pass it in directly and avoid the call
to page_folio() at the beginning.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230324180129.1220691-9-willy@infradead.orgSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/ext4.h

@@ -3756,9 +3756,8 @@ extern void ext4_io_submit_init(struct ext4_io_submit *io,
 				struct writeback_control *wbc);
 extern void ext4_end_io_rsv_work(struct work_struct *work);
 extern void ext4_io_submit(struct ext4_io_submit *io);
-extern int ext4_bio_write_page(struct ext4_io_submit *io,
-			       struct page *page,
-			       int len);
+int ext4_bio_write_folio(struct ext4_io_submit *io, struct folio *page,
+		size_t len);
 extern struct ext4_io_end_vec *ext4_alloc_io_end_vec(ext4_io_end_t *io_end);
 extern struct ext4_io_end_vec *ext4_last_io_end_vec(ext4_io_end_t *io_end);
 

fs/ext4/inode.c

@@ -1885,8 +1885,8 @@ static int mpage_submit_folio(struct mpage_da_data *mpd, struct folio *folio)
 	 * write-protects our page in page tables and the page cannot get
 	 * written to again until we release folio lock. So only after
 	 * folio_clear_dirty_for_io() we are safe to sample i_size for
-	 * ext4_bio_write_page() to zero-out tail of the written page. We rely
-	 * on the barrier provided by TestClearPageDirty in
+	 * ext4_bio_write_folio() to zero-out tail of the written page. We rely
+	 * on the barrier provided by folio_test_clear_dirty() in
 	 * folio_clear_dirty_for_io() to make sure i_size is really sampled only
 	 * after page tables are updated.
 	 */
@@ -1895,7 +1895,7 @@ static int mpage_submit_folio(struct mpage_da_data *mpd, struct folio *folio)
 	if (folio_pos(folio) + len > size &&
 	    !ext4_verity_in_progress(mpd->inode))
 		len = size & ~PAGE_MASK;
-	err = ext4_bio_write_page(&mpd->io_submit, &folio->page, len);
+	err = ext4_bio_write_folio(&mpd->io_submit, folio, len);
 	if (!err)
 		mpd->wbc->nr_to_write--;
 

fs/ext4/page-io.c

@@ -426,11 +426,9 @@ static void io_submit_add_bh(struct ext4_io_submit *io,
 	io->io_next_block++;
 }
 
-int ext4_bio_write_page(struct ext4_io_submit *io,
-			struct page *page,
-			int len)
+int ext4_bio_write_folio(struct ext4_io_submit *io, struct folio *folio,
+		size_t len)
 {
-	struct folio *folio = page_folio(page);
 	struct folio *io_folio = folio;
 	struct inode *inode = folio->mapping->host;
 	unsigned block_start;
@@ -523,8 +521,8 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 		if (io->io_bio)
 			gfp_flags = GFP_NOWAIT | __GFP_NOWARN;
 	retry_encrypt:
-		bounce_page = fscrypt_encrypt_pagecache_blocks(page, enc_bytes,
-							       0, gfp_flags);
+		bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page,
+					enc_bytes, 0, gfp_flags);
 		if (IS_ERR(bounce_page)) {
 			ret = PTR_ERR(bounce_page);
 			if (ret == -ENOMEM &&