collision_links
list_scb = LIST_NEXT(list_scb, collision_links);
LIST_INSERT_AFTER(first_scb, scb, collision_links);
LIST_INSERT_HEAD(free_list, scb, collision_links);
next_scb = LIST_NEXT(scb, collision_links);
LIST_REMOVE(scb, collision_links);
list_scb = LIST_NEXT(list_scb, collision_links);