ap_bus.c

linux 内核源代码

		if (ap_dev->queue_count > 0)
			*flags |= 1;
		break;
	case AP_RESPONSE_NO_PENDING_REPLY:
		if (status.queue_empty) {
			/* The card shouldn't forget requests but who knows. */
			atomic_sub(ap_dev->queue_count, &ap_poll_requests);
			ap_dev->queue_count = 0;
			list_splice_init(&ap_dev->pendingq, &ap_dev->requestq);
			ap_dev->requestq_count += ap_dev->pendingq_count;
			ap_dev->pendingq_count = 0;
		} else
			*flags |= 2;
		break;
	default:
		return -ENODEV;
	}
	return 0;
}

/**
 * Send messages from the request queue to an AP device.
 * @ap_dev: pointer to the AP device
 * @flags: pointer to control flags, bit 2^0 is set if another poll is
 *	   required, bit 2^1 is set if the poll timer needs to get armed
 * Returns 0 if the device is still present, -ENODEV if not.
 */
static int ap_poll_write(struct ap_device *ap_dev, unsigned long *flags)
{
	struct ap_queue_status status;
	struct ap_message *ap_msg;

	if (ap_dev->requestq_count <= 0 ||
	    ap_dev->queue_count >= ap_dev->queue_depth)
		return 0;
	/* Start the next request on the queue. */
	ap_msg = list_entry(ap_dev->requestq.next, struct ap_message, list);
	status = __ap_send(ap_dev->qid, ap_msg->psmid,
			   ap_msg->message, ap_msg->length);
	switch (status.response_code) {
	case AP_RESPONSE_NORMAL:
		atomic_inc(&ap_poll_requests);
		ap_increase_queue_count(ap_dev);
		list_move_tail(&ap_msg->list, &ap_dev->pendingq);
		ap_dev->requestq_count--;
		ap_dev->pendingq_count++;
		if (ap_dev->queue_count < ap_dev->queue_depth &&
		    ap_dev->requestq_count > 0)
			*flags |= 1;
		*flags |= 2;
		break;
	case AP_RESPONSE_Q_FULL:
	case AP_RESPONSE_RESET_IN_PROGRESS:
		*flags |= 2;
		break;
	case AP_RESPONSE_MESSAGE_TOO_BIG:
		return -EINVAL;
	default:
		return -ENODEV;
	}
	return 0;
}

/**
 * Poll AP device for pending replies and send new messages. If either
 * ap_poll_read or ap_poll_write returns -ENODEV unregister the device.
 * @ap_dev: pointer to the bus device
 * @flags: pointer to control flags, bit 2^0 is set if another poll is
 *	   required, bit 2^1 is set if the poll timer needs to get armed
 * Returns 0.
 */
static inline int ap_poll_queue(struct ap_device *ap_dev, unsigned long *flags)
{
	int rc;

	rc = ap_poll_read(ap_dev, flags);
	if (rc)
		return rc;
	return ap_poll_write(ap_dev, flags);
}

/**
 * Queue a message to a device.
 * @ap_dev: pointer to the AP device
 * @ap_msg: the message to be queued
 */
static int __ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
	struct ap_queue_status status;

	if (list_empty(&ap_dev->requestq) &&
	    ap_dev->queue_count < ap_dev->queue_depth) {
		status = __ap_send(ap_dev->qid, ap_msg->psmid,
				   ap_msg->message, ap_msg->length);
		switch (status.response_code) {
		case AP_RESPONSE_NORMAL:
			list_add_tail(&ap_msg->list, &ap_dev->pendingq);
			atomic_inc(&ap_poll_requests);
			ap_dev->pendingq_count++;
			ap_increase_queue_count(ap_dev);
			ap_dev->total_request_count++;
			break;
		case AP_RESPONSE_Q_FULL:
		case AP_RESPONSE_RESET_IN_PROGRESS:
			list_add_tail(&ap_msg->list, &ap_dev->requestq);
			ap_dev->requestq_count++;
			ap_dev->total_request_count++;
			return -EBUSY;
		case AP_RESPONSE_MESSAGE_TOO_BIG:
			ap_dev->drv->receive(ap_dev, ap_msg, ERR_PTR(-EINVAL));
			return -EINVAL;
		default:	/* Device is gone. */
			ap_dev->drv->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
			return -ENODEV;
		}
	} else {
		list_add_tail(&ap_msg->list, &ap_dev->requestq);
		ap_dev->requestq_count++;
		ap_dev->total_request_count++;
		return -EBUSY;
	}
	ap_schedule_poll_timer();
	return 0;
}

void ap_queue_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
	unsigned long flags;
	int rc;

	spin_lock_bh(&ap_dev->lock);
	if (!ap_dev->unregistered) {
		/* Make room on the queue by polling for finished requests. */
		rc = ap_poll_queue(ap_dev, &flags);
		if (!rc)
			rc = __ap_queue_message(ap_dev, ap_msg);
		if (!rc)
			wake_up(&ap_poll_wait);
		if (rc == -ENODEV)
			ap_dev->unregistered = 1;
	} else {
		ap_dev->drv->receive(ap_dev, ap_msg, ERR_PTR(-ENODEV));
		rc = -ENODEV;
	}
	spin_unlock_bh(&ap_dev->lock);
	if (rc == -ENODEV)
		device_unregister(&ap_dev->device);
}
EXPORT_SYMBOL(ap_queue_message);

/**
 * Cancel a crypto request. This is done by removing the request
 * from the devive pendingq or requestq queue. Note that the
 * request stays on the AP queue. When it finishes the message
 * reply will be discarded because the psmid can't be found.
 * @ap_dev: AP device that has the message queued
 * @ap_msg: the message that is to be removed
 */
void ap_cancel_message(struct ap_device *ap_dev, struct ap_message *ap_msg)
{
	struct ap_message *tmp;

	spin_lock_bh(&ap_dev->lock);
	if (!list_empty(&ap_msg->list)) {
		list_for_each_entry(tmp, &ap_dev->pendingq, list)
			if (tmp->psmid == ap_msg->psmid) {
				ap_dev->pendingq_count--;
				goto found;
			}
		ap_dev->requestq_count--;
	found:
		list_del_init(&ap_msg->list);
	}
	spin_unlock_bh(&ap_dev->lock);
}
EXPORT_SYMBOL(ap_cancel_message);

/**
 * AP receive polling for finished AP requests
 */
static void ap_poll_timeout(unsigned long unused)
{
	tasklet_schedule(&ap_tasklet);
}

/**
 * Reset a not responding AP device and move all requests from the
 * pending queue to the request queue.
 */
static void ap_reset(struct ap_device *ap_dev)
{
	int rc;

	ap_dev->reset = AP_RESET_IGNORE;
	atomic_sub(ap_dev->queue_count, &ap_poll_requests);
	ap_dev->queue_count = 0;
	list_splice_init(&ap_dev->pendingq, &ap_dev->requestq);
	ap_dev->requestq_count += ap_dev->pendingq_count;
	ap_dev->pendingq_count = 0;
	rc = ap_init_queue(ap_dev->qid);
	if (rc == -ENODEV)
		ap_dev->unregistered = 1;
}

/**
 * Poll all AP devices on the bus in a round robin fashion. Continue
 * polling until bit 2^0 of the control flags is not set. If bit 2^1
 * of the control flags has been set arm the poll timer.
 */
static int __ap_poll_all(struct ap_device *ap_dev, unsigned long *flags)
{
	spin_lock(&ap_dev->lock);
	if (!ap_dev->unregistered) {
		if (ap_poll_queue(ap_dev, flags))
			ap_dev->unregistered = 1;
		if (ap_dev->reset == AP_RESET_DO)
			ap_reset(ap_dev);
	}
	spin_unlock(&ap_dev->lock);
	return 0;
}

static void ap_poll_all(unsigned long dummy)
{
	unsigned long flags;
	struct ap_device *ap_dev;

	do {
		flags = 0;
		spin_lock(&ap_device_lock);
		list_for_each_entry(ap_dev, &ap_device_list, list) {
			__ap_poll_all(ap_dev, &flags);
		}
		spin_unlock(&ap_device_lock);
	} while (flags & 1);
	if (flags & 2)
		ap_schedule_poll_timer();
}

/**
 * AP bus poll thread. The purpose of this thread is to poll for
 * finished requests in a loop if there is a "free" cpu - that is
 * a cpu that doesn't have anything better to do. The polling stops
 * as soon as there is another task or if all messages have been
 * delivered.
 */
static int ap_poll_thread(void *data)
{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long flags;
	int requests;
	struct ap_device *ap_dev;

	set_user_nice(current, 19);
	while (1) {
		if (need_resched()) {
			schedule();
			continue;
		}
		add_wait_queue(&ap_poll_wait, &wait);
		set_current_state(TASK_INTERRUPTIBLE);
		if (kthread_should_stop())
			break;
		requests = atomic_read(&ap_poll_requests);
		if (requests <= 0)
			schedule();
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&ap_poll_wait, &wait);

		flags = 0;
		spin_lock_bh(&ap_device_lock);
		list_for_each_entry(ap_dev, &ap_device_list, list) {
			__ap_poll_all(ap_dev, &flags);
		}
		spin_unlock_bh(&ap_device_lock);
	}
	set_current_state(TASK_RUNNING);
	remove_wait_queue(&ap_poll_wait, &wait);
	return 0;
}

static int ap_poll_thread_start(void)
{
	int rc;

	mutex_lock(&ap_poll_thread_mutex);
	if (!ap_poll_kthread) {
		ap_poll_kthread = kthread_run(ap_poll_thread, NULL, "appoll");
		rc = IS_ERR(ap_poll_kthread) ? PTR_ERR(ap_poll_kthread) : 0;
		if (rc)
			ap_poll_kthread = NULL;
	}
	else
		rc = 0;
	mutex_unlock(&ap_poll_thread_mutex);
	return rc;
}

static void ap_poll_thread_stop(void)
{
	mutex_lock(&ap_poll_thread_mutex);
	if (ap_poll_kthread) {
		kthread_stop(ap_poll_kthread);
		ap_poll_kthread = NULL;
	}
	mutex_unlock(&ap_poll_thread_mutex);
}

/**
 * Handling of request timeouts
 */
static void ap_request_timeout(unsigned long data)
{
	struct ap_device *ap_dev = (struct ap_device *) data;

	if (ap_dev->reset == AP_RESET_ARMED)
		ap_dev->reset = AP_RESET_DO;
}

static void ap_reset_domain(void)
{
	int i;

	if (ap_domain_index != -1)
		for (i = 0; i < AP_DEVICES; i++)
			ap_reset_queue(AP_MKQID(i, ap_domain_index));
}

static void ap_reset_all(void)
{
	int i, j;

	for (i = 0; i < AP_DOMAINS; i++)
		for (j = 0; j < AP_DEVICES; j++)
			ap_reset_queue(AP_MKQID(j, i));
}

static struct reset_call ap_reset_call = {
	.fn = ap_reset_all,
};

/**
 * The module initialization code.
 */
int __init ap_module_init(void)
{
	int rc, i;

	if (ap_domain_index < -1 || ap_domain_index >= AP_DOMAINS) {
		printk(KERN_WARNING "Invalid param: domain = %d. "
		       " Not loading.\n", ap_domain_index);
		return -EINVAL;
	}
	if (ap_instructions_available() != 0) {
		printk(KERN_WARNING "AP instructions not installed.\n");
		return -ENODEV;
	}
	register_reset_call(&ap_reset_call);

	/* Create /sys/bus/ap. */
	rc = bus_register(&ap_bus_type);
	if (rc)
		goto out;
	for (i = 0; ap_bus_attrs[i]; i++) {
		rc = bus_create_file(&ap_bus_type, ap_bus_attrs[i]);
		if (rc)
			goto out_bus;
	}

	/* Create /sys/devices/ap. */
	ap_root_device = s390_root_dev_register("ap");
	rc = IS_ERR(ap_root_device) ? PTR_ERR(ap_root_device) : 0;
	if (rc)
		goto out_bus;

	ap_work_queue = create_singlethread_workqueue("kapwork");
	if (!ap_work_queue) {
		rc = -ENOMEM;
		goto out_root;
	}

	if (ap_select_domain() == 0)
		ap_scan_bus(NULL);

	/* Setup the ap bus rescan timer. */
	init_timer(&ap_config_timer);
	ap_config_timer.function = ap_config_timeout;
	ap_config_timer.data = 0;
	ap_config_timer.expires = jiffies + ap_config_time * HZ;
	add_timer(&ap_config_timer);

	/* Start the low priority AP bus poll thread. */
	if (ap_thread_flag) {
		rc = ap_poll_thread_start();
		if (rc)
			goto out_work;
	}

	return 0;

out_work:
	del_timer_sync(&ap_config_timer);
	del_timer_sync(&ap_poll_timer);
	destroy_workqueue(ap_work_queue);
out_root:
	s390_root_dev_unregister(ap_root_device);
out_bus:
	while (i--)
		bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
	bus_unregister(&ap_bus_type);
out:
	unregister_reset_call(&ap_reset_call);
	return rc;
}

static int __ap_match_all(struct device *dev, void *data)
{
	return 1;
}

/**
 * The module termination code
 */
void ap_module_exit(void)
{
	int i;
	struct device *dev;

	ap_reset_domain();
	ap_poll_thread_stop();
	del_timer_sync(&ap_config_timer);
	del_timer_sync(&ap_poll_timer);
	destroy_workqueue(ap_work_queue);
	tasklet_kill(&ap_tasklet);
	s390_root_dev_unregister(ap_root_device);
	while ((dev = bus_find_device(&ap_bus_type, NULL, NULL,
		    __ap_match_all)))
	{
		device_unregister(dev);
		put_device(dev);
	}
	for (i = 0; ap_bus_attrs[i]; i++)
		bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
	bus_unregister(&ap_bus_type);
	unregister_reset_call(&ap_reset_call);
}

#ifndef CONFIG_ZCRYPT_MONOLITHIC
module_init(ap_module_init);
module_exit(ap_module_exit);
#endif