linux-kernel - Re: [PATCH v2 02/10] x86/percpu: Clean up percpu_to

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Message-ID: <CAMzpN2i3TPxpf5ktaQgb5EmB9wd84V+J5U6=_MuihtXx1-cp+A@mail.gmail.com>
Date:   Fri, 10 Jul 2020 00:38:23 -0400
From:   Brian Gerst <brgerst@...il.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: Re: [PATCH v2 02/10] x86/percpu: Clean up percpu_to_op()

On Thu, Jul 9, 2020 at 6:30 AM Peter Zijlstra <peterz@...radead.org> wrote:
>
> On Sat, May 30, 2020 at 06:11:19PM -0400, Brian Gerst wrote:
> > +     if (0) {                                                        \
> > +             typeof(_var) pto_tmp__;                                 \
> > +             pto_tmp__ = (_val);                                     \
> > +             (void)pto_tmp__;                                        \
> > +     }                                                               \
>
> This is repeated at least once more; and it looks very similar to
> __typecheck() and typecheck() but is yet another variant afaict.

The problem with typecheck() is that it will complain about a mismatch
between unsigned long and u64 (defined as unsigned long long) even
though both are 64-bits wide on x86-64.  Cleaning that mess up is
beyond the scope of this series, so I kept the existing checks.

--
Brian Gerst