Re: [PATCH v2 1/9] drm/i915: Remove superfluous NULL check

Takashi Iwai
2015-12-04T12:54:59Z

On Fri, 04 Dec 2015 13:16:46 +0100,
Ville Syrjälä wrote:
>
> On Tue, Dec 01, 2015 at 05:09:50PM +0100, Takashi Iwai wrote:
> > to_intel_crtc() always returns a non-NULL pointer.
>
> Eh? to_intel_crtc(NULL) should return NULL or we might have tons of
> breakage on our hands. Or maybe the atomic work has gotten rid of that
> assumption, but at least we used to depend on that heavily.

Well, to_intel_crtc() has been always container_of() since the very
beginning of universe:

commit 79e539453b34e35f39299a899d263b0a1f1670bd
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Fri Nov 7 14:24:08 2008 -0800

DRM: i915: add mode setting support

--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_drv.h
....
+#define to_intel_crtc(x) container_of(x, struct intel_crtc, base)
....

Takashi

>
> >
> > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > ---
> > drivers/gpu/drm/i915/intel_audio.c | 4 ----
> > 1 file changed, 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> > index 4dccd9b003a1..0c38cc6c82ae 100644
> > --- a/drivers/gpu/drm/i915/intel_audio.c
> > +++ b/drivers/gpu/drm/i915/intel_audio.c
> > @@ -656,10 +656,6 @@ static int i915_audio_component_sync_audio_rate(struct device *dev,
> > intel_dig_port = enc_to_dig_port(&intel_encoder->base);
> > if (port == intel_dig_port->port) {
> > crtc = to_intel_crtc(intel_encoder->base.crtc);
> > - if (!crtc) {
> > - DRM_DEBUG_KMS("%s: crtc is NULL\n", __func__);
> > - continue;
> > - }
> > pipe = crtc->pipe;
> > break;
> > }
> > --
> > 2.6.3
>
> --
> Ville Syrjälä
> Intel OTC