erofs: Convert erofs zdata to read_folio

This is a "weak" conversion which converts straight back to using pages.
A full conversion should be performed at some point, hopefully by
someone familiar with the filesystem.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs/erofs/zdata.c

@@ -791,7 +791,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 static bool z_erofs_get_sync_decompress_policy(struct erofs_sb_info *sbi,
 				       unsigned int readahead_pages)
 {
-	/* auto: enable for readpage, disable for readahead */
+	/* auto: enable for read_folio, disable for readahead */
 	if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO) &&
 	    !readahead_pages)
 		return true;
@@ -1488,8 +1488,9 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
 	}
 }
 
-static int z_erofs_readpage(struct file *file, struct page *page)
+static int z_erofs_read_folio(struct file *file, struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct inode *const inode = page->mapping->host;
 	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
 	struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
@@ -1563,6 +1564,6 @@ static void z_erofs_readahead(struct readahead_control *rac)
 }
 
 const struct address_space_operations z_erofs_aops = {
-	.readpage = z_erofs_readpage,
+	.read_folio = z_erofs_read_folio,
 	.readahead = z_erofs_readahead,
 };