[PATCH 4/5] drm/vmwgfx: remove custom ioctl io encoding check

[Thomas Hellstrom]

On Fri, 2019-05-24 at 13:14 +0100, Emil Velikov wrote:
> On 2019/05/23, Thomas Hellstrom wrote:
> > Hi, Emil,
> > 
> > On Wed, 2019-05-22 at 17:41 +0100, Emil Velikov wrote:
> > > From: Emil Velikov <emil.velikov at collabora.com>
> > > 
> > > Drop the custom ioctl io encoding check - core drm does it for
> > > us.
> > 
> > I fail to see where the core does this, or do I miss something?
> 
> drm_ioctl() allows for the encoding to be changed and attributes that
> only the
> appropriate size is copied in/out of the kernel.
> 
> Technically the function is more relaxed relative to the vmwgfx
> check, yet
> seems perfectly reasonable.
> 
> Is there any corner-case that isn't but should be handled in
> drm_ioctl()?

I'd like to turn the question around and ask whether there's a reason
we should relax the vmwgfx test? In the past it has trapped quite a few
user-space errors.

Thanks,
Thomas



> 
> -Emil