Re: [Intel-gfx] [PATCH 2/6] drm/i915: add helper functions to get device ptr

From: Jani Nikula <jani.nikula@intel.com>
To: "Bharadiya\,Pankaj" <pankaj.laxminarayan.bharadiya@intel.com>
Cc: pankaj.laxminaryan.bharadiya@outlook.iglb.intel.com,
	David Airlie <airlied@linux.ie>,
	intel-gfx@lists.freedesktop.org, sudeep.dutt@intel.com,
	dri-devel@lists.freedesktop.org,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	sam@ravnborg.org, Zhi Wang <zhi.a.wang@intel.com>
Subject: Re: [Intel-gfx] [PATCH 2/6] drm/i915: add helper functions to get device ptr
Date: Tue, 14 Jan 2020 09:51:29 +0200	[thread overview]
Message-ID: <87o8v6jx1a.fsf@intel.com> (raw)
In-Reply-To: <20200113183158.GA739@plaxmina-desktop.iind.intel.com>

On Tue, 14 Jan 2020, "Bharadiya,Pankaj" <pankaj.laxminarayan.bharadiya@intel.com> wrote:
> Hi Jani, 
>
> On Mon, Jan 13, 2020 at 02:14:51PM +0200, Jani Nikula wrote:
>> On Mon, 13 Jan 2020, Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> wrote:
>> > We will need struct drm_device pointer to pass it to drm_WARN* calls.
>> >
>> > Add helper functions to exract drm_device pointer from various structs.
>> 
>> Please don't do this.
>> 
>> We use the helpers we currently have when they involve something more
>> complex than dereferences, such as container_of() or having to use
>> dev_get_drvdata() or pci_get_drvdata().
>
> Removing all the helpers will lead to 3 level access depth wherever
> struct drm_device pointer is needed and unnecessary complicate the
> drm_WARN* calls IMHO.
>
> e.g.: drm_WARN(&vgpu->gvt->dev_priv.drm, 1)
>
> If you are OK with this, I will remove all the helpers and extract
> drm_device pointer while calling drm_WARN*() instead and submit
> updated patch series.

At times you may need to add local variables for struct drm_i915_private
*i915. But I'd rather have that than the helpers.

BR,
Jani.

>
> Thanks,
> Pankaj
>> 
>> I really don't want people to use e.g.
>> 
>> 	i915_to_dev(i915)
>> 
>> over
>> 
>> 	&i915->drm
>> 
>> 
>> BR,
>> Jani.
>> 
>> >
>> > Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_display_types.h | 14 ++++++++++++++
>> >  drivers/gpu/drm/i915/gvt/gvt.h                     |  5 +++++
>> >  drivers/gpu/drm/i915/i915_drv.h                    | 11 +++++++++++
>> >  3 files changed, 30 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
>> > index 7964b3dc0046..765878718fe9 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> > @@ -1521,6 +1521,20 @@ dp_to_i915(struct intel_dp *intel_dp)
>> >  	return to_i915(dp_to_dig_port(intel_dp)->base.base.dev);
>> >  }
>> >  
>> > +static inline struct drm_device *enc_to_dev(const struct intel_encoder *encoder)
>> > +{
>> > +	return encoder->base.dev;
>> > +}
>> > +
>> > +static inline struct drm_device *
>> > +crtc_state_to_dev(const struct intel_crtc_state *state)
>> > +{
>> > +	struct intel_crtc *crtc = to_intel_crtc(state->uapi.crtc);
>> > +	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
>> > +
>> > +	return i915_to_dev(i915);
>> > +}
>> > +
>> >  static inline struct intel_digital_port *
>> >  hdmi_to_dig_port(struct intel_hdmi *intel_hdmi)
>> >  {
>> > diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
>> > index b47c6acaf9c0..d257399b075a 100644
>> > --- a/drivers/gpu/drm/i915/gvt/gvt.h
>> > +++ b/drivers/gpu/drm/i915/gvt/gvt.h
>> > @@ -348,6 +348,11 @@ static inline struct intel_gvt *to_gvt(struct drm_i915_private *i915)
>> >  	return i915->gvt;
>> >  }
>> >  
>> > +static inline struct drm_device *vgpu_to_dev(const struct intel_vgpu *vgpu)
>> > +{
>> > +	return i915_to_dev(vgpu->gvt->dev_priv);
>> > +}
>> > +
>> >  enum {
>> >  	INTEL_GVT_REQUEST_EMULATE_VBLANK = 0,
>> >  
>> > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> > index e7be4c3e43c6..bdc89d021ff8 100644
>> > --- a/drivers/gpu/drm/i915/i915_drv.h
>> > +++ b/drivers/gpu/drm/i915/i915_drv.h
>> > @@ -1325,6 +1325,17 @@ static inline struct drm_i915_private *pdev_to_i915(struct pci_dev *pdev)
>> >  	return pci_get_drvdata(pdev);
>> >  }
>> >  
>> > +static inline struct drm_device *i915_to_dev(struct drm_i915_private *i915)
>> > +{
>> > +	return &i915->drm;
>> > +}
>> > +
>> > +static inline struct drm_device *
>> > +perf_stream_to_dev(const struct i915_perf_stream *stream)
>> > +{
>> > +	return i915_to_dev(stream->perf->i915);
>> > +}
>> > +
>> >  /* Simple iterator over all initialised engines */
>> >  #define for_each_engine(engine__, dev_priv__, id__) \
>> >  	for ((id__) = 0; \
>> 
>> -- 
>> Jani Nikula, Intel Open Source Graphics Center

-- 
Jani Nikula, Intel Open Source Graphics Center
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel