linux-kernel - Re: syscall_get_error() && TS

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Message-ID: <CA+55aFzbbLZaWvg+vTEKrfzZkwb=iAVUK5cZu2LxdbevZiGJ2g@mail.gmail.com>
Date:   Wed, 29 Mar 2017 09:59:38 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Oleg Nesterov <oleg@...hat.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Jan Kratochvil <jan.kratochvil@...hat.com>,
        Pedro Alves <palves@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: syscall_get_error() && TS_ checks

On Wed, Mar 29, 2017 at 9:55 AM, Oleg Nesterov <oleg@...hat.com> wrote:
>
> Once again, it is only used in arch/x86/kernel/signal.c by do_signal() and
> handle_signal(). We do not care if mmap() returns a valid pointer with the
> high bit set, regs-ax can't be confused with -ERESTART code.

Immaterial. If the function is called "get_error()", it sure as hell
shouldn't return a random non-error value.

Code should make sense, otherwise it's not going to be maintainable.
Naming matters. If the code doesn't match the name of the function,
that's a bug regardless of whether it has semantic effects or not in
the end - because somebody will eventually depend on the _expected_
semantics.

              Linus