migrate: convert __unmap_and_move() to use folios

	return rc;

}

static int __unmap_and_move(struct page *page, struct page *newpage,

static int __unmap_and_move(struct folio *src, struct folio *dst,

				int force, enum migrate_mode mode)

{

	struct folio *folio = page_folio(page);

	struct folio *dst = page_folio(newpage);

	int rc = -EAGAIN;

	bool page_was_mapped = false;

	struct anon_vma *anon_vma = NULL;

	bool is_lru = !__PageMovable(page);

	bool is_lru = !__PageMovable(&src->page);

	if (!trylock_page(page)) {

	if (!folio_trylock(src)) {

		if (!force || mode == MIGRATE_ASYNC)

			goto out;

		if (current->flags & PF_MEMALLOC)

			goto out;

		lock_page(page);

		folio_lock(src);

	}

	if (PageWriteback(page)) {

	if (folio_test_writeback(src)) {

		/*

		 * Only in the case of a full synchronous migration is it

		 * necessary to wait for PageWriteback. In the async case,

		}

		if (!force)

			goto out_unlock;

		wait_on_page_writeback(page);

		folio_wait_writeback(src);

	}

	/*

	 * By try_to_migrate(), page->mapcount goes down to 0 here. In this case,

	 * we cannot notice that anon_vma is freed while we migrates a page.

	 * By try_to_migrate(), src->mapcount goes down to 0 here. In this case,

	 * we cannot notice that anon_vma is freed while we migrate a page.

	 * This get_anon_vma() delays freeing anon_vma pointer until the end

	 * of migration. File cache pages are no problem because of page_lock()

	 * File Caches may use write_page() or lock_page() in migration, then,

	 * because that implies that the anon page is no longer mapped

	 * (and cannot be remapped so long as we hold the page lock).

	 */

	if (PageAnon(page) && !PageKsm(page))

		anon_vma = page_get_anon_vma(page);

	if (folio_test_anon(src) && !folio_test_ksm(src))

		anon_vma = page_get_anon_vma(&src->page);

	/*

	 * Block others from accessing the new page when we get around to

	 * establishing additional references. We are usually the only one

	 * holding a reference to newpage at this point. We used to have a BUG

	 * here if trylock_page(newpage) fails, but would like to allow for

	 * cases where there might be a race with the previous use of newpage.

	 * holding a reference to dst at this point. We used to have a BUG

	 * here if folio_trylock(dst) fails, but would like to allow for

	 * cases where there might be a race with the previous use of dst.

	 * This is much like races on refcount of oldpage: just don't BUG().

	 */

	if (unlikely(!trylock_page(newpage)))

	if (unlikely(!folio_trylock(dst)))

		goto out_unlock;

	if (unlikely(!is_lru)) {

		rc = move_to_new_folio(dst, folio, mode);

		rc = move_to_new_folio(dst, src, mode);

		goto out_unlock_both;

	}

	 * Corner case handling:

	 * 1. When a new swap-cache page is read into, it is added to the LRU

	 * and treated as swapcache but it has no rmap yet.

	 * Calling try_to_unmap() against a page->mapping==NULL page will

	 * Calling try_to_unmap() against a src->mapping==NULL page will

	 * trigger a BUG.  So handle it here.

	 * 2. An orphaned page (see truncate_cleanup_page) might have

	 * fs-private metadata. The page can be picked up due to memory

	 * invisible to the vm, so the page can not be migrated.  So try to

	 * free the metadata, so the page can be freed.

	 */

	if (!page->mapping) {

		VM_BUG_ON_PAGE(PageAnon(page), page);

		if (page_has_private(page)) {

			try_to_free_buffers(folio);

	if (!src->mapping) {

		if (folio_test_private(src)) {

			try_to_free_buffers(src);

			goto out_unlock_both;

		}

	} else if (page_mapped(page)) {

	} else if (folio_mapped(src)) {

		/* Establish migration ptes */

		VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,

				page);

		try_to_migrate(folio, 0);

		VM_BUG_ON_FOLIO(folio_test_anon(src) &&

			       !folio_test_ksm(src) && !anon_vma, src);

		try_to_migrate(src, 0);

		page_was_mapped = true;

	}

	if (!page_mapped(page))

		rc = move_to_new_folio(dst, folio, mode);

	if (!folio_mapped(src))

		rc = move_to_new_folio(dst, src, mode);

	/*

	 * When successful, push newpage to LRU immediately: so that if it

	 * When successful, push dst to LRU immediately: so that if it

	 * turns out to be an mlocked page, remove_migration_ptes() will

	 * automatically build up the correct newpage->mlock_count for it.

	 * automatically build up the correct dst->mlock_count for it.

	 *

	 * We would like to do something similar for the old page, when

	 * unsuccessful, and other cases when a page has been temporarily

	 * isolated from the unevictable LRU: but this case is the easiest.

	 */

	if (rc == MIGRATEPAGE_SUCCESS) {

		lru_cache_add(newpage);

		folio_add_lru(dst);

		if (page_was_mapped)

			lru_add_drain();

	}

	if (page_was_mapped)

		remove_migration_ptes(folio,

			rc == MIGRATEPAGE_SUCCESS ? dst : folio, false);

		remove_migration_ptes(src,

			rc == MIGRATEPAGE_SUCCESS ? dst : src, false);

out_unlock_both:

	unlock_page(newpage);

	folio_unlock(dst);

out_unlock:

	/* Drop an anon_vma reference if we took one */

	if (anon_vma)

		put_anon_vma(anon_vma);

	unlock_page(page);

	folio_unlock(src);

out:

	/*

	 * If migration is successful, decrease refcount of the newpage,

	 * If migration is successful, decrease refcount of dst,

	 * which will not free the page because new page owner increased

	 * refcounter.

	 */

	if (rc == MIGRATEPAGE_SUCCESS)

		put_page(newpage);

		folio_put(dst);

	return rc;

}

				   enum migrate_reason reason,

				   struct list_head *ret)

{

	struct folio *dst, *src = page_folio(page);

	int rc = MIGRATEPAGE_SUCCESS;

	struct page *newpage = NULL;

	newpage = get_new_page(page, private);

	if (!newpage)

		return -ENOMEM;

	dst = page_folio(newpage);

	newpage->private = 0;

	rc = __unmap_and_move(page, newpage, force, mode);

	rc = __unmap_and_move(src, dst, force, mode);

	if (rc == MIGRATEPAGE_SUCCESS)

		set_page_owner_migrate_reason(newpage, reason);