From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

By implementing ->writepages instead of ->writepage, we remove a
layer of indirect function calls from the writeback path and the
last use of struct page in nilfs2.

[ konishi.ryusuke: fixed panic by using buffer_migrate_folio_norefs ]
Link: https://lkml.kernel.org/r/20241002150036.1339475-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
---
 fs/nilfs2/mdt.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index a4c1e00aaaac..432181cfb0b5 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -399,10 +399,9 @@ int nilfs_mdt_fetch_dirty(struct inode *inode)
 	return test_bit(NILFS_I_DIRTY, &ii->i_state);
 }
 
-static int
-nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
+static int nilfs_mdt_write_folio(struct folio *folio,
+		struct writeback_control *wbc)
 {
-	struct folio *folio = page_folio(page);
 	struct inode *inode = folio->mapping->host;
 	struct super_block *sb;
 	int err = 0;
@@ -435,11 +434,23 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 	return err;
 }
 
+static int nilfs_mdt_writeback(struct address_space *mapping,
+		struct writeback_control *wbc)
+{
+	struct folio *folio = NULL;
+	int error;
+
+	while ((folio = writeback_iter(mapping, wbc, folio, &error)))
+		error = nilfs_mdt_write_folio(folio, wbc);
+
+	return error;
+}
 
 static const struct address_space_operations def_mdt_aops = {
 	.dirty_folio		= block_dirty_folio,
 	.invalidate_folio	= block_invalidate_folio,
-	.writepage		= nilfs_mdt_write_page,
+	.writepages		= nilfs_mdt_writeback,
+	.migrate_folio		= buffer_migrate_folio_norefs,
 };
 
 static const struct inode_operations def_mdt_iops;
-- 
2.43.0