mm: shmem: use new radix tree iterator

					pgoff_t start, unsigned int nr_pages,

					struct page **pages, pgoff_t *indices)

{

	unsigned int i;

	unsigned int ret;

	unsigned int nr_found;

	void **slot;

	unsigned int ret = 0;

	struct radix_tree_iter iter;

	if (!nr_pages)

		return 0;

	rcu_read_lock();

restart:

	nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree,

				(void ***)pages, indices, start, nr_pages);

	ret = 0;

	for (i = 0; i < nr_found; i++) {

	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {

		struct page *page;

repeat:

		page = radix_tree_deref_slot((void **)pages[i]);

		page = radix_tree_deref_slot(slot);

		if (unlikely(!page))

			continue;

		if (radix_tree_exception(page)) {

			goto repeat;

		/* Has the page moved? */

		if (unlikely(page != *((void **)pages[i]))) {

		if (unlikely(page != *slot)) {

			page_cache_release(page);

			goto repeat;

		}

export:

		indices[ret] = indices[i];

		indices[ret] = iter.index;

		pages[ret] = page;

		ret++;

		if (++ret == nr_pages)

			break;

	}

	if (unlikely(!ret && nr_found))

		goto restart;

	rcu_read_unlock();

	return ret;

}