linux-kernel - Re: [PATCH] MIPS: kernel: proc: Remove spurious white space in cpuinfo

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Date:   Fri, 20 Oct 2017 16:56:51 -0700
From:   David Daney <ddaney@...iumnetworks.com>
To:     "Maciej W. Rozycki" <macro@...s.com>,
        Aleksandar Markovic <aleksandar.markovic@...rk.com>
Cc:     linux-mips@...ux-mips.org,
        Dragan Cecavac <dragan.cecavac@...s.com>,
        Aleksandar Markovic <aleksandar.markovic@...s.com>,
        Douglas Leung <douglas.leung@...s.com>,
        Goran Ferenc <goran.ferenc@...s.com>,
        James Hogan <james.hogan@...s.com>,
        James Hogan <jhogan@...nel.org>, linux-kernel@...r.kernel.org,
        "Maciej W. Rozycki" <macro@...ux-mips.org>,
        Miodrag Dinic <miodrag.dinic@...s.com>,
        Paul Burton <paul.burton@...tec.com>,
        Paul Burton <paul.burton@...s.com>,
        Petar Jovanovic <petar.jovanovic@...s.com>,
        Raghu Gandham <raghu.gandham@...s.com>,
        Ralf Baechle <ralf@...ux-mips.org>
Subject: Re: [PATCH] MIPS: kernel: proc: Remove spurious white space in
 cpuinfo

On 10/20/2017 01:47 PM, Maciej W. Rozycki wrote:
> On Fri, 20 Oct 2017, Aleksandar Markovic wrote:
> 
>> Remove unnecessary space from FPU info segment of /proc/cpuinfo.
> 
>   NAK.  As I recall back in Nov 2001 I placed the extra space there to
> visually separate the CPU part from the FPU part, e.g.:
> 
> cpu model		: R3000A V3.0  FPU V4.0
> cpu model		: SiByte SB1 V0.2  FPU V0.2
> 
> etc.  And the motivation behind it still stands.  Please remember that
> /proc/cpuinfo is there for live humans to parse and grouping all these
> pieces together would make it harder.  Which means your change adds no
> value I'm afraid.

I think it is even riskier than that.  This is part of the 
kernel-userspace ABI, many programs parse this file, any gratuitous 
changes risk breaking something.

I don't really have an opinion about the various *printf functions being 
used, but think the resultant change in what is visible to userspace 
should not be done.

> 
>   NB regrettably back in those days much of the patch traffic happened off
> any mailing list, however I have quickly tracked down my archival copy of
> the original submission of the change introducing this piece of code and
> I'll be happy to share it with anyone upon request.
> 
>    Maciej
>