On Wed, Aug 14, 2019 at 10:42:28PM +0200, Arnd Bergmann wrote:
> For 31-bit s390 user space, we have to pass pointer arguments through
> compat_ptr() in the compat_ioctl handler.
Seems fair enough, but...
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> fs/xfs/xfs_ioctl32.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
> index 7fcf7569743f..ad91e81a2fcf 100644
> --- a/fs/xfs/xfs_ioctl32.c
> +++ b/fs/xfs/xfs_ioctl32.c
> @@ -547,7 +547,7 @@ xfs_file_compat_ioctl(
> struct inode *inode = file_inode(filp);
> struct xfs_inode *ip = XFS_I(inode);
> struct xfs_mount *mp = ip->i_mount;
> - void __user *arg = (void __user *)p;
> + void __user *arg = compat_ptr(p);
> int error;
>
> trace_xfs_file_compat_ioctl(ip);
> @@ -576,7 +576,7 @@ xfs_file_compat_ioctl(
> case XFS_IOC_SCRUB_METADATA:
> case XFS_IOC_BULKSTAT:
> case XFS_IOC_INUMBERS:
> - return xfs_file_ioctl(filp, cmd, p);
> + return xfs_file_ioctl(filp, cmd, (unsigned long)arg);
I don't really like having to sprinkle special casts through the
code because of this.
Perhaps do something like:
static inline unsigned long compat_ptr_mask(unsigned long p)
{
return (unsigned long)compat_ptr(p);
}
and then up front you can do:
void __user *arg;
p = compat_ptr_mask(p);
arg = (void __user *)p;
and then the rest of the code remains unchanged by now uses p
correctly instead of having to change all the code to cast arg back
to an unsigned long...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
