static int linereq_create()

in gpiolib-cdev.c [1313:1457]

• 108 lines of code
• 24 McCabe index (conditional complexity)

static int linereq_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpio_v2_line_request ulr;
	struct gpio_v2_line_config *lc;
	struct linereq *lr;
	struct file *file;
	u64 flags;
	unsigned int i;
	int fd, ret;

	if (copy_from_user(&ulr, ip, sizeof(ulr)))
		return -EFAULT;

	if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
		return -EINVAL;

	if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
		return -EINVAL;

	lc = &ulr.config;
	ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
	if (ret)
		return ret;

	lr = kzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
	if (!lr)
		return -ENOMEM;

	lr->gdev = gdev;
	get_device(&gdev->dev);

	for (i = 0; i < ulr.num_lines; i++) {
		lr->lines[i].req = lr;
		WRITE_ONCE(lr->lines[i].sw_debounced, 0);
		INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
	}

	if (ulr.consumer[0] != '\0') {
		/* label is only initialized if consumer is set */
		lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
				     GFP_KERNEL);
		if (!lr->label) {
			ret = -ENOMEM;
			goto out_free_linereq;
		}
	}

	mutex_init(&lr->config_mutex);
	init_waitqueue_head(&lr->wait);
	lr->event_buffer_size = ulr.event_buffer_size;
	if (lr->event_buffer_size == 0)
		lr->event_buffer_size = ulr.num_lines * 16;
	else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
		lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;

	atomic_set(&lr->seqno, 0);
	lr->num_lines = ulr.num_lines;

	/* Request each GPIO */
	for (i = 0; i < ulr.num_lines; i++) {
		u32 offset = ulr.offsets[i];
		struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);

		if (IS_ERR(desc)) {
			ret = PTR_ERR(desc);
			goto out_free_linereq;
		}

		ret = gpiod_request(desc, lr->label);
		if (ret)
			goto out_free_linereq;

		lr->lines[i].desc = desc;
		flags = gpio_v2_line_config_flags(lc, i);
		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);

		ret = gpiod_set_transitory(desc, false);
		if (ret < 0)
			goto out_free_linereq;

		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
			int val = gpio_v2_line_config_output_value(lc, i);

			ret = gpiod_direction_output(desc, val);
			if (ret)
				goto out_free_linereq;
		} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				goto out_free_linereq;

			ret = edge_detector_setup(&lr->lines[i], lc, i,
					flags & GPIO_V2_LINE_EDGE_FLAGS);
			if (ret)
				goto out_free_linereq;
		}

		blocking_notifier_call_chain(&desc->gdev->notifier,
					     GPIO_V2_LINE_CHANGED_REQUESTED, desc);

		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
			offset);
	}

	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		ret = fd;
		goto out_free_linereq;
	}

	file = anon_inode_getfile("gpio-line", &line_fileops, lr,
				  O_RDONLY | O_CLOEXEC);
	if (IS_ERR(file)) {
		ret = PTR_ERR(file);
		goto out_put_unused_fd;
	}

	ulr.fd = fd;
	if (copy_to_user(ip, &ulr, sizeof(ulr))) {
		/*
		 * fput() will trigger the release() callback, so do not go onto
		 * the regular error cleanup path here.
		 */
		fput(file);
		put_unused_fd(fd);
		return -EFAULT;
	}

	fd_install(fd, file);

	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
		lr->num_lines);

	return 0;

out_put_unused_fd:
	put_unused_fd(fd);
out_free_linereq:
	linereq_free(lr);
	return ret;
}