[Intel-gfx] [PATCH 63/70] drm/i915: Reduce locking inside swfinish ioctl

[Chris Wilson]

On Fri, Apr 10, 2015 at 11:14:56AM +0200, Daniel Vetter wrote:
> On Tue, Apr 7, 2015 at 6:28 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> >         /* Pinned buffers may be scanout, so flush the cache */
> > -       if (obj->pin_display)
> > +       if (obj->pin_display) {
> > +               ret = i915_mutex_lock_interruptible(dev);
> > +               if (ret)
> > +                       goto unref;
> 
> I think and ACCESS_ONCE here and in the previous one would be good.
> Wanted to do that and merge both, but they seem to conflict with the
> lack of read-read ...

What do you want to accomplish with ACCESS_ONCE()? Unfortunately as we
can't use it on bitfields.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre