static int watchdog_cdev_register()

in watchdog_dev.c [988:1074]

• 68 lines of code
• 10 McCabe index (conditional complexity)

static int watchdog_cdev_register(struct watchdog_device *wdd)
{
	struct watchdog_core_data *wd_data;
	int err;

	wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL);
	if (!wd_data)
		return -ENOMEM;
	mutex_init(&wd_data->lock);

	wd_data->wdd = wdd;
	wdd->wd_data = wd_data;

	if (IS_ERR_OR_NULL(watchdog_kworker)) {
		kfree(wd_data);
		return -ENODEV;
	}

	device_initialize(&wd_data->dev);
	wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id);
	wd_data->dev.class = &watchdog_class;
	wd_data->dev.parent = wdd->parent;
	wd_data->dev.groups = wdd->groups;
	wd_data->dev.release = watchdog_core_data_release;
	dev_set_drvdata(&wd_data->dev, wdd);
	dev_set_name(&wd_data->dev, "watchdog%d", wdd->id);

	kthread_init_work(&wd_data->work, watchdog_ping_work);
	hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
	wd_data->timer.function = watchdog_timer_expired;
	watchdog_hrtimer_pretimeout_init(wdd);

	if (wdd->id == 0) {
		old_wd_data = wd_data;
		watchdog_miscdev.parent = wdd->parent;
		err = misc_register(&watchdog_miscdev);
		if (err != 0) {
			pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n",
				wdd->info->identity, WATCHDOG_MINOR, err);
			if (err == -EBUSY)
				pr_err("%s: a legacy watchdog module is probably present.\n",
					wdd->info->identity);
			old_wd_data = NULL;
			put_device(&wd_data->dev);
			return err;
		}
	}

	/* Fill in the data structures */
	cdev_init(&wd_data->cdev, &watchdog_fops);

	/* Add the device */
	err = cdev_device_add(&wd_data->cdev, &wd_data->dev);
	if (err) {
		pr_err("watchdog%d unable to add device %d:%d\n",
			wdd->id,  MAJOR(watchdog_devt), wdd->id);
		if (wdd->id == 0) {
			misc_deregister(&watchdog_miscdev);
			old_wd_data = NULL;
			put_device(&wd_data->dev);
		}
		return err;
	}

	wd_data->cdev.owner = wdd->ops->owner;

	/* Record time of most recent heartbeat as 'just before now'. */
	wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1);
	watchdog_set_open_deadline(wd_data);

	/*
	 * If the watchdog is running, prevent its driver from being unloaded,
	 * and schedule an immediate ping.
	 */
	if (watchdog_hw_running(wdd)) {
		__module_get(wdd->ops->owner);
		get_device(&wd_data->dev);
		if (handle_boot_enabled)
			hrtimer_start(&wd_data->timer, 0,
				      HRTIMER_MODE_REL_HARD);
		else
			pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n",
				wdd->id);
	}

	return 0;
}