[patch 03/11] Add compat handlers for data & rt growfs ioctls

[Christoph Hellwig]

On Tue, Nov 18, 2008 at 10:44:04PM -0600, sandeen at sandeen.net wrote:
> The args for XFS_IOC_FSGROWFSDATA and XFS_IOC_FSGROWFSRTA
> have padding on the end on intel, so add arg copyin functions,
> and then just call the native ioctl.
> 
> Signed-off-by: Eric Sandeen <sandeen at sandeen.net>
> --
> 
> Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_ioctl32.c
> ===================================================================
> --- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_ioctl32.c
> +++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_ioctl32.c
> @@ -87,6 +87,28 @@ xfs_ioc_fsgeometry_v1_compat(
>  	return 0;
>  }
>  
> +STATIC unsigned long
> +xfs_ioctl32_growfs_data_copyin(unsigned long arg)
> +{
> +	compat_xfs_growfs_data_t __user *p32 = (void __user *)arg;
> +	xfs_growfs_data_t __user *p = compat_alloc_user_space(sizeof(*p));
> +
> +	if (copy_in_user(p, p32, sizeof(*p32)))
> +		return -XFS_ERROR(EFAULT);
> +	return (unsigned long)p;
> +}

As mentioned in reply to the first patch I think this would be better
as:

STATIC unsigned long
xfs_ioctl32_growfs_data(
	struct xfs_mount		*mp,
	void __user			*argp)
{
	compat_xfs_growfs_data_t	in32;
	xfs_growfs_data_t		in;

	if (copy_from_user(&in, arg, sizeof(in32)))
		return -XFS_ERROR(EFAULT);
	in.newblocks = in32.newblocks;
	in.imaxpct = in32.imaxpct;
	return -xfs_growfs_data(mp, &in);
}

and same for the rt version.  Also all these alignment only adjustments
really needs comments explaining what we're doing here as it's not
obvious.