linux-kernel - Re: [PATCH] drm/amdgpu: do not initialise global variables to 0 or NULL

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Message-ID: <20201103153407.GB3267686@kroah.com>
Date:   Tue, 3 Nov 2020 16:34:07 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     "Deucher, Alexander" <Alexander.Deucher@....com>
Cc:     "Koenig, Christian" <Christian.Koenig@....com>,
        Alex Deucher <alexdeucher@...il.com>,
        Deepak R Varma <mh12gx2825@...il.com>,
        David Airlie <airlied@...ux.ie>,
        LKML <linux-kernel@...r.kernel.org>,
        Maling list - DRI developers 
        <dri-devel@...ts.freedesktop.org>,
        Melissa Wen <melissa.srw@...il.com>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        Daniel Vetter <daniel@...ll.ch>,
        Daniel Vetter <daniel.vetter@...ll.ch>
Subject: Re: [PATCH] drm/amdgpu: do not initialise global variables to 0 or
 NULL

On Tue, Nov 03, 2020 at 02:50:40PM +0000, Deucher, Alexander wrote:
> [AMD Public Use]
> 
> > -----Original Message-----
> > From: Greg KH <gregkh@...uxfoundation.org>
> > Sent: Tuesday, November 3, 2020 1:53 AM
> > To: Koenig, Christian <Christian.Koenig@....com>
> > Cc: Alex Deucher <alexdeucher@...il.com>; Deepak R Varma
> > <mh12gx2825@...il.com>; David Airlie <airlied@...ux.ie>; LKML <linux-
> > kernel@...r.kernel.org>; Maling list - DRI developers <dri-
> > devel@...ts.freedesktop.org>; Melissa Wen <melissa.srw@...il.com>;
> > amd-gfx list <amd-gfx@...ts.freedesktop.org>; Daniel Vetter
> > <daniel@...ll.ch>; Daniel Vetter <daniel.vetter@...ll.ch>; Deucher,
> > Alexander <Alexander.Deucher@....com>
> > Subject: Re: [PATCH] drm/amdgpu: do not initialise global variables to 0 or
> > NULL
> > 
> > On Mon, Nov 02, 2020 at 09:06:21PM +0100, Christian König wrote:
> > > Am 02.11.20 um 20:43 schrieb Alex Deucher:
> > > > On Mon, Nov 2, 2020 at 1:42 PM Deepak R Varma
> > <mh12gx2825@...il.com> wrote:
> > > > > Initializing global variable to 0 or NULL is not necessary and
> > > > > should be avoided. Issue reported by checkpatch script as:
> > > > > ERROR: do not initialise globals to 0 (or NULL).
> > > > I agree that this is technically correct, but a lot of people don't
> > > > seem to know that so we get a lot of comments about this code for
> > > > the variables that are not explicitly set.  Seems less confusing to
> > > > initialize them even if it not necessary.  I don't have a
> > > > particularly strong opinion on it however.
> > >
> > > Agree with Alex.
> > >
> > > Especially for the module parameters we should have a explicit init
> > > value for documentation purposes, even when it is 0.
> > 
> > Why is this one tiny driver somehow special compared to the entire rest of
> > the kernel?  (hint, it isn't...)
> > 
> > Please follow the normal coding style rules, there's no reason to ignore them
> > unless you like to constantly reject patches like this that get sent to you.
> > 
> 
> I'll apply the patch, but as a data point, this is the first time I've
> gotten a patch to make this change.  I get several bug reports or
> patches every year to explicitly set values to global variables
> because users assume they are not initialized.  So it will always be a
> trade off as to which patches you want to NACK.

Are you all not running your patches through checkpatch.pl to tell you
simple things like this?  If no, I suggest you start doing that :)

thanks,

greg k-h