bcache: Don't reinvent the wheel but use existing llist API

	list = llist_del_all(&wait_list->list);

	/* We first reverse the list to preserve FIFO ordering and fairness */

	while (list) {

		struct llist_node *t = list;

		list = llist_next(list);

		t->next = reverse;

		reverse = t;

	}

	reverse = llist_reverse_order(list);

	/* Then do the wakeups */

	while (reverse) {

		cl = container_of(reverse, struct closure, list);

		reverse = llist_next(reverse);

	llist_for_each_entry(cl, reverse, list) {

		closure_set_waiting(cl, 0);

		closure_sub(cl, CLOSURE_WAITING + 1);

	}