node_t *new_item = node_alloc(new_key, new_val);
node_t *next = new_item->next = old_item;
node_t *other = SYNC_CAS(&pred->next, next, new_item);
node_t *new_item = node_alloc(new_key, new_val);
node_t *next = new_item->next = old_item;
node_t *other = SYNC_CAS(&pred->next, next, new_item);