static int do_bufconfig_ioctl(struct comedi_device *dev,
			      struct comedi_bufconfig __user *arg)
{
	struct comedi_bufconfig bc;
	struct comedi_async *async;
	struct comedi_subdevice *s;
	int retval = 0;

	if (copy_from_user(&bc, arg, sizeof(struct comedi_bufconfig)))
		return -EFAULT;

	if (bc.subdevice >= dev->n_subdevices || bc.subdevice < 0)
		return -EINVAL;

	s = dev->subdevices + bc.subdevice;
	async = s->async;

	if (!async) {
		DPRINTK("subdevice does not have async capability\n");
		bc.size = 0;
		bc.maximum_size = 0;
		goto copyback;
	}

	if (bc.maximum_size) {
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;

		async->max_bufsize = bc.maximum_size;
	}

	if (bc.size) {
		retval = resize_async_buffer(dev, s, async, bc.size);
		if (retval < 0)
			return retval;
	}

	bc.size = async->prealloc_bufsz;
	bc.maximum_size = async->max_bufsize;

copyback:
	if (copy_to_user(arg, &bc, sizeof(struct comedi_bufconfig)))
		return -EFAULT;

	return 0;
}
static int do_bufconfig_ioctl(struct comedi_device *dev,
			      struct comedi_bufconfig __user *arg)
{
	struct comedi_bufconfig bc;
	struct comedi_async *async;
	struct comedi_subdevice *s;
	int retval = 0;

	if (copy_from_user(&bc, arg, sizeof(struct comedi_bufconfig)))
		return -EFAULT;

	if (bc.subdevice >= dev->n_subdevices || bc.subdevice < 0)
		return -EINVAL;

	s = dev->subdevices + bc.subdevice;
	async = s->async;

	if (!async) {
		DPRINTK("subdevice does not have async capability\n");
		bc.size = 0;
		bc.maximum_size = 0;
		goto copyback;
	}

	if (bc.maximum_size) {
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;

		async->max_bufsize = bc.maximum_size;
	}

	if (bc.size) {
		retval = resize_async_buffer(dev, s, async, bc.size);
		if (retval < 0)
			return retval;
	}

	bc.size = async->prealloc_bufsz;
	bc.maximum_size = async->max_bufsize;

copyback:
	if (copy_to_user(arg, &bc, sizeof(struct comedi_bufconfig)))
		return -EFAULT;

	return 0;
}