[PATCH RFC 08/29] mm/migrate: rename putback_movable_folio() to putback_movable_ops_page()

[David Hildenbrand]

... and factor the complete handling of movable_ops pages out.
Convert it similar to isolate_movable_ops_page().

While at it, convert the VM_BUG_ON_FOLIO() into a VM_WARN_ON_PAGE().

Signed-off-by: David Hildenbrand <da...@redhat.com>
---
 mm/migrate.c | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 6bbb455f8b593..32e77898f7d6c 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -133,12 +133,30 @@ bool isolate_movable_ops_page(struct page *page, 
isolate_mode_t mode)
        return false;
 }
 
-static void putback_movable_folio(struct folio *folio)
+/**
+ * putback_movable_ops_page - putback an isolated movable_ops page
+ * @page: The isolated page.
+ *
+ * Putback an isolated movable_ops page.
+ *
+ * After the page was putback, it might get freed instantly.
+ */
+static void putback_movable_ops_page(struct page *page)
 {
-       const struct movable_operations *mops = folio_movable_ops(folio);
-
-       mops->putback_page(&folio->page);
-       folio_clear_isolated(folio);
+       /*
+        * TODO: these pages will not be folios in the future. All
+        * folio dependencies will have to be removed.
+        */
+       struct folio *folio = page_folio(page);
+
+       VM_WARN_ON_ONCE_PAGE(!PageIsolated(page), page);
+       folio_lock(folio);
+       /* If the page was released by it's owner, there is nothing to do. */
+       if (PageMovable(page))
+               page_movable_ops(page)->putback_page(page);
+       ClearPageIsolated(page);
+       folio_unlock(folio);
+       folio_put(folio);
 }
 
 /*
@@ -166,14 +184,7 @@ void putback_movable_pages(struct list_head *l)
                 * have PAGE_MAPPING_MOVABLE.
                 */
                if (unlikely(__folio_test_movable(folio))) {
-                       VM_BUG_ON_FOLIO(!folio_test_isolated(folio), folio);
-                       folio_lock(folio);
-                       if (folio_test_movable(folio))
-                               putback_movable_folio(folio);
-                       else
-                               folio_clear_isolated(folio);
-                       folio_unlock(folio);
-                       folio_put(folio);
+                       putback_movable_ops_page(&folio->page);
                } else {
                        node_stat_mod_folio(folio, NR_ISOLATED_ANON +
                                        folio_is_file_lru(folio), 
-folio_nr_pages(folio));
-- 
2.49.0