Re: [PATCH] Add compat_ioctl to st

[Christoph Hellwig <hch@infradead.org>]

> +#ifdef CONFIG_COMPAT
> +static int st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> +	struct scsi_tape *STp = file->private_data;
> +	struct scsi_device *sdev = STp->device;
> +	int ret = -ENOIOCTLCMD;
> +	if (sdev->host->hostt->compat_ioctl) { 
> +
> +		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, arg);

This seems to miss a cast for arg.  Also I think it would be really nice
to have a little helper like:

int scsi_compat_ioctl(struct scsi_device *sdev, unsigned int cmd,
		unsiged long arg)
{
	struct scsi_host_template *hostt = sdev->host->hostt;
	if (hostt->compat_ioctl)
		return hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
	return -ENOIOCTLCMD;
}

that all drivers could use.