static int linehandle_create()

in gpiolib-cdev.c [285:404]

• 89 lines of code
• 19 McCabe index (conditional complexity)

static int linehandle_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpiohandle_request handlereq;
	struct linehandle_state *lh;
	struct file *file;
	int fd, i, ret;
	u32 lflags;

	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
		return -EFAULT;
	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
		return -EINVAL;

	lflags = handlereq.flags;

	ret = linehandle_validate_flags(lflags);
	if (ret)
		return ret;

	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
	if (!lh)
		return -ENOMEM;
	lh->gdev = gdev;
	get_device(&gdev->dev);

	if (handlereq.consumer_label[0] != '\0') {
		/* label is only initialized if consumer_label is set */
		lh->label = kstrndup(handlereq.consumer_label,
				     sizeof(handlereq.consumer_label) - 1,
				     GFP_KERNEL);
		if (!lh->label) {
			ret = -ENOMEM;
			goto out_free_lh;
		}
	}

	lh->num_descs = handlereq.lines;

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

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

		ret = gpiod_request(desc, lh->label);
		if (ret)
			goto out_free_lh;
		lh->descs[i] = desc;
		linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);

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

		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
			int val = !!handlereq.default_values[i];

			ret = gpiod_direction_output(desc, val);
			if (ret)
				goto out_free_lh;
		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				goto out_free_lh;
		}

		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_lh;
	}

	file = anon_inode_getfile("gpio-linehandle",
				  &linehandle_fileops,
				  lh,
				  O_RDONLY | O_CLOEXEC);
	if (IS_ERR(file)) {
		ret = PTR_ERR(file);
		goto out_put_unused_fd;
	}

	handlereq.fd = fd;
	if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
		/*
		 * 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",
		lh->num_descs);

	return 0;

out_put_unused_fd:
	put_unused_fd(fd);
out_free_lh:
	linehandle_free(lh);
	return ret;
}