Merge tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull final writepage conversion from Christian Brauner:
 "This converts vboxfs from ->writepage() to ->writepages().

  This was the last user of the ->writepage() method. So remove
  ->writepage() completely and all references to it"

* tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: Remove aops->writepage
  mm: Remove swap_writepage() and shmem_writepage()
  ttm: Call shmem_writeout() from ttm_backup_backup_page()
  i915: Use writeback_iter()
  shmem: Add shmem_writeout()
  writeback: Remove writeback_use_writepage()
  migrate: Remove call to ->writepage
  vboxsf: Convert to writepages
  9p: Add a migrate_folio method

1 files changed, 7 insertions, 53 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 676d9cfc7059..c80591514e66 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -947,66 +947,20 @@ int filemap_migrate_folio(struct address_space *mapping,
 EXPORT_SYMBOL_GPL(filemap_migrate_folio);
 
 /*
- * Writeback a folio to clean the dirty state
- */
-static int writeout(struct address_space *mapping, struct folio *folio)
-{
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_NONE,
-		.nr_to_write = 1,
-		.range_start = 0,
-		.range_end = LLONG_MAX,
-		.for_reclaim = 1
-	};
-	int rc;
-
-	if (!mapping->a_ops->writepage)
-		/* No write method for the address space */
-		return -EINVAL;
-
-	if (!folio_clear_dirty_for_io(folio))
-		/* Someone else already triggered a write */
-		return -EAGAIN;
-
-	/*
-	 * A dirty folio may imply that the underlying filesystem has
-	 * the folio on some queue. So the folio must be clean for
-	 * migration. Writeout may mean we lose the lock and the
-	 * folio state is no longer what we checked for earlier.
-	 * At this point we know that the migration attempt cannot
-	 * be successful.
-	 */
-	remove_migration_ptes(folio, folio, 0);
-
-	rc = mapping->a_ops->writepage(&folio->page, &wbc);
-
-	if (rc != AOP_WRITEPAGE_ACTIVATE)
-		/* unlocked. Relock */
-		folio_lock(folio);
-
-	return (rc < 0) ? -EIO : -EAGAIN;
-}
-
-/*
  * Default handling if a filesystem does not provide a migration function.
  */
 static int fallback_migrate_folio(struct address_space *mapping,
 		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
-	if (folio_test_dirty(src)) {
-		/* Only writeback folios in full synchronous migration */
-		switch (mode) {
-		case MIGRATE_SYNC:
-			break;
-		default:
-			return -EBUSY;
-		}
-		return writeout(mapping, src);
-	}
+	WARN_ONCE(mapping->a_ops->writepages,
+			"%ps does not implement migrate_folio\n",
+			mapping->a_ops);
+	if (folio_test_dirty(src))
+		return -EBUSY;
 
 	/*
-	 * Buffers may be managed in a filesystem specific way.
-	 * We must have no buffers or drop them.
+	 * Filesystem may have private data at folio->private that we
+	 * can't migrate automatically.
 	 */
 	if (!filemap_release_folio(src, GFP_KERNEL))
 		return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;