Re: [PATCH] Support compat_ioctl for block devices

[Andi Kleen <ak@muc.de>]

On Tue, Jan 18, 2005 at 09:19:27AM +0000, Christoph Hellwig wrote:
> > +long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
> > +{
> > +	struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
> > +	struct gendisk *disk = bdev->bd_disk;
> > +	int ret = -ENOIOCTLCMD;
> > +	if (disk->fops->compat_ioctl) {
> > +		lock_kernel();
> > +		ret = disk->fops->compat_ioctl(file, cmd, arg);
> > +		unlock_kernel();
> > +	}
> > +	return ret;
> > +}
> 
>  - please don't introduce a new API with the BKL held.

Nope, I'm not going to audit zillions of low level functions for this.

>  - prototype isn't nice.  just passing the gendisk for block_device
>    should be enough.

No, it isn't, the compat handler needs cmd and arg, and file is useful
when you pass it to an existing ioctl handler.

-Andi