bcachefs: Delete bch_writepage

Per Dave Chinner and the xfs folks, .writepage is no longer needed, and
it's better not to define it if .writepages is the intended path.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/fs-io.c

@@ -1469,20 +1469,6 @@ int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc
 	return ret;
 }
 
-int bch2_writepage(struct page *page, struct writeback_control *wbc)
-{
-	struct bch_fs *c = page->mapping->host->i_sb->s_fs_info;
-	struct bch_writepage_state w =
-		bch_writepage_state_init(c, to_bch_ei(page->mapping->host));
-	int ret;
-
-	ret = __bch2_writepage(page_folio(page), wbc, &w);
-	if (w.io)
-		bch2_writepage_do_io(&w);
-
-	return ret;
-}
-
 /* buffered writes: */
 
 int bch2_write_begin(struct file *file, struct address_space *mapping,

fs/bcachefs/fs-io.h

@@ -15,7 +15,6 @@ int __must_check bch2_write_inode_size(struct bch_fs *,
 				       struct bch_inode_info *,
 				       loff_t, unsigned);
 
-int bch2_writepage(struct page *, struct writeback_control *);
 int bch2_read_folio(struct file *, struct folio *);
 
 int bch2_writepages(struct address_space *, struct writeback_control *);

fs/bcachefs/fs.c

@@ -1113,7 +1113,6 @@ static const struct inode_operations bch_special_inode_operations = {
 };
 
 static const struct address_space_operations bch_address_space_operations = {
-	.writepage	= bch2_writepage,
 	.read_folio	= bch2_read_folio,
 	.writepages	= bch2_writepages,
 	.readahead	= bch2_readahead,