On Mon, Aug 11, 2014 at 01:25:49PM +0200, Daniel Vetter wrote: > On Mon, Aug 11, 2014 at 11:26:07AM +0100, Chris Wilson wrote: > > On Mon, Aug 11, 2014 at 01:14:50PM +0300, Jani Nikula wrote: > > > On Sat, 09 Aug 2014, Chris Wilson <ch...@chris-wilson.co.uk> wrote: > > > > Adapt the macro so that we can pass either the struct drm_device or the > > > > struct drm_i915_private pointers and get the answer we want. Over time, > > > > my plan is to convert all users over to using drm_i915_private and so > > > > trimming down the pointer dance. Having spent a few hours chasing that > > > > goal and achieved over 8k of object code saving, it appears to be a > > > > worthwhile target. This interim macro allows us to slowly convert over. > > > > > > > > Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> > > > > --- > > > > drivers/gpu/drm/i915/i915_dma.c | 3 +++ > > > > drivers/gpu/drm/i915/i915_drv.h | 3 ++- > > > > 2 files changed, 5 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/i915_dma.c > > > > b/drivers/gpu/drm/i915/i915_dma.c > > > > index 39988940d468..49149406fcd8 100644 > > > > --- a/drivers/gpu/drm/i915/i915_dma.c > > > > +++ b/drivers/gpu/drm/i915/i915_dma.c > > > > @@ -1585,6 +1585,9 @@ int i915_driver_load(struct drm_device *dev, > > > > unsigned long flags) > > > > if (!drm_core_check_feature(dev, DRIVER_MODESET) && !dev->agp) > > > > return -EINVAL; > > > > > > > > + /* For the ugly agnostic INTEL_INFO macro */ > > > > + BUILD_BUG_ON(sizeof(*dev_priv) == sizeof(*dev)); > > > > + > > > > dev_priv = kzalloc(sizeof(*dev_priv), GFP_KERNEL); > > > > if (dev_priv == NULL) > > > > return -ENOMEM; > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.h > > > > b/drivers/gpu/drm/i915/i915_drv.h > > > > index 0aef763ffa75..e66465430bdc 100644 > > > > --- a/drivers/gpu/drm/i915/i915_drv.h > > > > +++ b/drivers/gpu/drm/i915/i915_drv.h > > > > @@ -2063,7 +2063,8 @@ struct drm_i915_cmd_table { > > > > int count; > > > > }; > > > > > > > > -#define INTEL_INFO(p) (&to_i915(p)->info) > > > > +#define __I915__(p) ((sizeof(*(p)) == sizeof(struct > > > > drm_i915_private)) ? (struct drm_i915_private *)(p) : to_i915((struct > > > > drm_device *)p)) > > > > > > The explicit casts make me uncomfortable. Indeed, aren't they completely > > > unnecessary? If the sizeof matches, p is expected to be struct > > > drm_i915_private *, and if not, it's expected to be struct drm_device *, > > > right? > > > > Yes, killing the typesafety is bad. Sadly it is to quiesce the compiler > > as the type-mismatch warnings are generated before it does the dead code > > elimination removing the constant ?: expression. Too bad we couldn't > > simply write typeof(*p) == typeof(T). > > Do we need the 2nd cast for (struct drm_device *)? If we could drop that > we'd have about as much type-safety as before, presuming no one manages to > matche our drm_i915_private exactly in size.
The compiler is happy with that. I can't remember exactly why I added it first time, it certainly wasn't for its looks. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx