linux-kernel - Re: [PATCH -next 0/8] drm/amd/amdgpu: fix comparison pointer to bool warning

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Date:   Wed, 16 Sep 2020 09:51:56 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     christian.koenig@....com
Cc:     Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>,
        Alex Deucher <alexdeucher@...il.com>, yi.zhang@...wei.com,
        Dave Airlie <airlied@...ux.ie>,
        LKML <linux-kernel@...r.kernel.org>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        Zheng Bin <zhengbin13@...wei.com>,
        Maling list - DRI developers 
        <dri-devel@...ts.freedesktop.org>,
        "Deucher, Alexander" <alexander.deucher@....com>
Subject: Re: [PATCH -next 0/8] drm/amd/amdgpu: fix comparison pointer to bool
 warning

On Wed, Sep 16, 2020 at 09:38:34AM +0200, Christian König wrote:
> Am 15.09.20 um 21:35 schrieb Ville Syrjälä:
> > On Tue, Sep 15, 2020 at 03:16:32PM -0400, Alex Deucher wrote:
> > > I question the value of these warnings.  Why even have a boolean type
> > > if you are going to get warnings when you use them...
> > > That said, applied to avoid getting these patches again and again
> > > every time someone sees this.
> > if (this_is_sparta)
> > if (this_is_sparta == true)
> > if (this_is_sparta != false)
> > 
> > I think the first one reads the best, and avoids having to
> > decide between truth and falsehood :)
> 
> +1

+1, especially because we also have the inversion when using negative
errno codes for failures and 0 as success, which results in

	if (errno == 0) /* success case */

but
	if (bool == 0) /* failure case */

now creative people do sometimes

	if (!errno) /* success case */

which I think is horribly confusing. So imo for more easier telling apart
of these too I think consistently using the short form for booleans, and
consistently using the more explicit long form for errno checks is a Very
Good Pattern :-)

Cheers, Daniel

> 
> Christian.
> 
> > 
> > > Alex
> > > 
> > > On Wed, Sep 9, 2020 at 9:21 AM Christian König <christian.koenig@....com> wrote:
> > > > Acked-by: Christian König <christian.koenig@....com> for the series.
> > > > 
> > > > Am 09.09.20 um 15:07 schrieb Zheng Bin:
> > > > > Zheng Bin (8):
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in gfx_v9_0.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in gfx_v10_0.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in sdma_v5_0.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in sdma_v5_2.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in si.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in uvd_v6_0.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in
> > > > >       amdgpu_atpx_handler.c
> > > > >     drm/amd/amdgpu: fix comparison pointer to bool warning in sdma_v4_0.c
> > > > > 
> > > > >    drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c | 4 ++--
> > > > >    drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c           | 2 +-
> > > > >    drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c            | 2 +-
> > > > >    drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c           | 4 ++--
> > > > >    drivers/gpu/drm/amd/amdgpu/sdma_v5_0.c           | 2 +-
> > > > >    drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c           | 2 +-
> > > > >    drivers/gpu/drm/amd/amdgpu/si.c                  | 2 +-
> > > > >    drivers/gpu/drm/amd/amdgpu/uvd_v6_0.c            | 4 ++--
> > > > >    8 files changed, 11 insertions(+), 11 deletions(-)
> > > > > 
> > > > > --
> > > > > 2.26.0.106.g9fadedd
> > > > > 
> > > > _______________________________________________
> > > > amd-gfx mailing list
> > > > amd-gfx@...ts.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel@...ts.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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