static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
				  unsigned long arg)
{
	const unsigned minor = iminor(file->f_dentry->d_inode);
	struct comedi_device_file_info *dev_file_info =
	    comedi_get_device_file_info(minor);
	struct comedi_device *dev;
	int rc;

	if (dev_file_info == NULL || dev_file_info->device == NULL)
		return -ENODEV;
	dev = dev_file_info->device;

	mutex_lock(&dev->mutex);

	/* Device config is special, because it must work on
	 * an unconfigured device. */
	if (cmd == COMEDI_DEVCONFIG) {
		rc = do_devconfig_ioctl(dev,
					(struct comedi_devconfig __user *)arg);
		goto done;
	}

	if (!dev->attached) {
		DPRINTK("no driver configured on /dev/comedi%i\n", dev->minor);
		rc = -ENODEV;
		goto done;
	}

	switch (cmd) {
	case COMEDI_BUFCONFIG:
		rc = do_bufconfig_ioctl(dev,
					(struct comedi_bufconfig __user *)arg);
		break;
	case COMEDI_DEVINFO:
		rc = do_devinfo_ioctl(dev, (struct comedi_devinfo __user *)arg,
				      file);
		break;
	case COMEDI_SUBDINFO:
		rc = do_subdinfo_ioctl(dev,
				       (struct comedi_subdinfo __user *)arg,
				       file);
		break;
	case COMEDI_CHANINFO:
		rc = do_chaninfo_ioctl(dev, (void __user *)arg);
		break;
	case COMEDI_RANGEINFO:
		rc = do_rangeinfo_ioctl(dev, (void __user *)arg);
		break;
	case COMEDI_BUFINFO:
		rc = do_bufinfo_ioctl(dev,
				      (struct comedi_bufinfo __user *)arg,
				      file);
		break;
	case COMEDI_LOCK:
		rc = do_lock_ioctl(dev, arg, file);
		break;
	case COMEDI_UNLOCK:
		rc = do_unlock_ioctl(dev, arg, file);
		break;
	case COMEDI_CANCEL:
		rc = do_cancel_ioctl(dev, arg, file);
		break;
	case COMEDI_CMD:
		rc = do_cmd_ioctl(dev, (struct comedi_cmd __user *)arg, file);
		break;
	case COMEDI_CMDTEST:
		rc = do_cmdtest_ioctl(dev, (struct comedi_cmd __user *)arg,
				      file);
		break;
	case COMEDI_INSNLIST:
		rc = do_insnlist_ioctl(dev,
				       (struct comedi_insnlist __user *)arg,
				       file);
		break;
	case COMEDI_INSN:
		rc = do_insn_ioctl(dev, (struct comedi_insn __user *)arg,
				   file);
		break;
	case COMEDI_POLL:
		rc = do_poll_ioctl(dev, arg, file);
		break;
	default:
		rc = -ENOTTY;
		break;
	}

done:
	mutex_unlock(&dev->mutex);
	return rc;
}

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