fs: Remove aops->migratepage()

With all users converted to migrate_folio(), remove this operation.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

include/linux/fs.h

@@ -367,8 +367,6 @@ struct address_space_operations {
 	 */
 	int (*migrate_folio)(struct address_space *, struct folio *dst,
 			struct folio *src, enum migrate_mode);
-	int (*migratepage) (struct address_space *,
-			struct page *, struct page *, enum migrate_mode);
 	int (*launder_folio)(struct folio *);
 	bool (*is_partially_uptodate) (struct folio *, size_t from,
 			size_t count);

mm/compaction.c

@@ -1031,7 +1031,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 			/*
 			 * Only pages without mappings or that have a
-			 * ->migratepage callback are possible to migrate
+			 * ->migrate_folio callback are possible to migrate
 			 * without blocking. However, we can be racing with
 			 * truncation so it's necessary to lock the page
 			 * to stabilise the mapping as truncation holds
@@ -1043,8 +1043,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 			mapping = page_mapping(page);
 			migrate_dirty = !mapping ||
-					mapping->a_ops->migrate_folio ||
-					mapping->a_ops->migratepage;
+					mapping->a_ops->migrate_folio;
 			unlock_page(page);
 			if (!migrate_dirty)
 				goto isolate_fail_put;

mm/migrate.c

@@ -909,9 +909,6 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 			 */
 			rc = mapping->a_ops->migrate_folio(mapping, dst, src,
 								mode);
-		else if (mapping->a_ops->migratepage)
-			rc = mapping->a_ops->migratepage(mapping, &dst->page,
-							&src->page, mode);
 		else
 			rc = fallback_migrate_folio(mapping, dst, src, mode);
 	} else {