[PATCH 20/20] mm/folio-compat: Remove migration compatibility functions

[Matthew Wilcox (Oracle)]

migrate_page_move_mapping(), migrate_page_copy() and migrate_page_states()
are all now unused after converting all the filesystems from
aops->migratepage() to aops->migrate_folio().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/migrate.h | 11 -----------
 mm/folio-compat.c       | 22 ----------------------
 mm/ksm.c                |  2 +-
 3 files changed, 1 insertion(+), 34 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 088749471485..4670f3aec232 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -33,12 +33,8 @@ extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
 extern struct page *alloc_migration_target(struct page *page, unsigned long private);
 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
 
-extern void migrate_page_states(struct page *newpage, struct page *page);
-extern void migrate_page_copy(struct page *newpage, struct page *page);
 int migrate_huge_page_move_mapping(struct address_space *mapping,
 		struct folio *dst, struct folio *src);
-extern int migrate_page_move_mapping(struct address_space *mapping,
-		struct page *newpage, struct page *page, int extra_count);
 void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
 				spinlock_t *ptl);
 void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
@@ -59,13 +55,6 @@ static inline struct page *alloc_migration_target(struct page *page,
 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
 	{ return -EBUSY; }
 
-static inline void migrate_page_states(struct page *newpage, struct page *page)
-{
-}
-
-static inline void migrate_page_copy(struct page *newpage,
-				     struct page *page) {}
-
 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
 				  struct folio *dst, struct folio *src)
 {
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 20bc15b57d93..458618c7302c 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -51,28 +51,6 @@ void mark_page_accessed(struct page *page)
 }
 EXPORT_SYMBOL(mark_page_accessed);
 
-#ifdef CONFIG_MIGRATION
-int migrate_page_move_mapping(struct address_space *mapping,
-		struct page *newpage, struct page *page, int extra_count)
-{
-	return folio_migrate_mapping(mapping, page_folio(newpage),
-					page_folio(page), extra_count);
-}
-EXPORT_SYMBOL(migrate_page_move_mapping);
-
-void migrate_page_states(struct page *newpage, struct page *page)
-{
-	folio_migrate_flags(page_folio(newpage), page_folio(page));
-}
-EXPORT_SYMBOL(migrate_page_states);
-
-void migrate_page_copy(struct page *newpage, struct page *page)
-{
-	folio_migrate_copy(page_folio(newpage), page_folio(page));
-}
-EXPORT_SYMBOL(migrate_page_copy);
-#endif
-
 bool set_page_writeback(struct page *page)
 {
 	return folio_start_writeback(page_folio(page));
diff --git a/mm/ksm.c b/mm/ksm.c
index 54f78c9eecae..e8f8c1a2bb39 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -712,7 +712,7 @@ static struct page *get_ksm_page(struct stable_node *stable_node,
 	 * however, it might mean that the page is under page_ref_freeze().
 	 * The __remove_mapping() case is easy, again the node is now stale;
 	 * the same is in reuse_ksm_page() case; but if page is swapcache
-	 * in migrate_page_move_mapping(), it might still be our page,
+	 * in folio_migrate_mapping(), it might still be our page,
 	 * in which case it's essential to keep the node.
 	 */
 	while (!get_page_unless_zero(page)) {
-- 
2.35.1