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

[Daniel Vetter <daniel@ffwll.ch>]

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@amd.com> wrote:
> > > > Acked-by: Christian König <christian.koenig@amd.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
> > > > > 
> > > > _______________________________________________
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> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch