V_task_queue
taskqueue_enqueue(V_task_queue, &V_task);
taskqueue_enqueue(V_task_queue, &V_task);
V_task_queue = taskqueue_create_fast("ip_mroute_tskq", M_NOWAIT,
taskqueue_thread_enqueue, &V_task_queue);
taskqueue_start_threads(&V_task_queue, 1, PI_NET, "ip_mroute_tskq task");
taskqueue_free(V_task_queue);
taskqueue_cancel(V_task_queue, &V_task, NULL);
taskqueue_unblock(V_task_queue);
taskqueue_block(V_task_queue);
while (taskqueue_cancel(V_task_queue, &V_task, NULL)) {
taskqueue_drain(V_task_queue, &V_task);
taskqueue_cancel(V_task_queue, &V_task, NULL);