Function taskq_destroy

freebsd/contrib/openzfs/module/os/linux/spl/spl-taskq.c:1143–1226

EXPORT_SYMBOL(taskq_create);

void
taskq_destroy(taskq_t *tq)
{
	struct task_struct *thread;
	taskq_thread_t *tqt;
	taskq_ent_t *t;
	unsigned long flags;

	ASSERT(tq);
	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
	tq->tq_flags &= ~TASKQ_ACTIVE;
	spin_unlock_irqrestore(&tq->tq_lock, flags);

#ifdef HAVE_CPU_HOTPLUG
	if (tq->tq_hp_support) {
		VERIFY0(cpuhp_state_remove_instance_nocalls(
		    spl_taskq_cpuhp_state, &tq->tq_hp_cb_node));
	}
#endif
	/*
	 * When TASKQ_ACTIVE is clear new tasks may not be added nor may
	 * new worker threads be spawned for dynamic taskq.
	 */
	if (dynamic_taskq != NULL)
		taskq_wait_outstanding(dynamic_taskq, 0);

	taskq_wait(tq);

	/* remove taskq from global list used by the kstats */
	down_write(&tq_list_sem);
	list_del(&tq->tq_taskqs);
	up_write(&tq_list_sem);

	spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
	/* wait for spawning threads to insert themselves to the list */
	while (tq->tq_nspawn) {
		spin_unlock_irqrestore(&tq->tq_lock, flags);
		schedule_timeout_interruptible(1);
		spin_lock_irqsave_nested(&tq->tq_lock, flags,
		    tq->tq_lock_class);
	}

	/*
	 * Signal each thread to exit and block until it does.  Each thread
	 * is responsible for removing itself from the list and freeing its
	 * taskq_thread_t.  This allows for idle threads to opt to remove
	 * themselves from the taskq.  They can be recreated as needed.
	 */
	while (!list_empty(&tq->tq_thread_list)) {
		tqt = list_entry(tq->tq_thread_list.next,
		    taskq_thread_t, tqt_thread_list);
		thread = tqt->tqt_thread;
		spin_unlock_irqrestore(&tq->tq_lock, flags);

		kthread_stop(thread);

		spin_lock_irqsave_nested(&tq->tq_lock, flags,
		    tq->tq_lock_class);