linux-kernel - Re: [PATCH] sparc: time: Use pointer from memcpy() call for assignment in setup_sparc64

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Message-ID: <CAMuHMdX-uKt3-Lb2NaxmONEqWdtFgTOqXEo1nOfGq-R8ysHfcQ@mail.gmail.com>
Date: Fri, 31 Oct 2025 09:01:01 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Markus Elfring <Markus.Elfring@....de>
Cc: sparclinux@...r.kernel.org, 
	Alexandre Belloni <alexandre.belloni@...tlin.com>, Andreas Larsson <andreas@...sler.com>, 
	Christoph Lameter <cl@...ux.com>, "David S. Miller" <davem@...emloft.net>, Finn Thain <fthain@...ux-m68k.org>, 
	Tejun Heo <tj@...nel.org>, LKML <linux-kernel@...r.kernel.org>, 
	kernel-janitors@...r.kernel.org, Miaoqian Lin <linmq006@...il.com>
Subject: Re: [PATCH] sparc: time: Use pointer from memcpy() call for
 assignment in setup_sparc64_timer()

Hi Markus,

On Fri, 31 Oct 2025 at 08:46, Markus Elfring <Markus.Elfring@....de> wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Fri, 31 Oct 2025 08:36:13 +0100
>
> A pointer was assigned to a variable. The same pointer was used for
> the destination parameter of a memcpy() call.
> This function is documented in the way that the same value is returned.
> Thus convert two separate statements into a direct variable assignment for
> the return value from a memory copy action.
>
> The source code was transformed by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>

Thanks for your patch!

> --- a/arch/sparc/kernel/time_64.c
> +++ b/arch/sparc/kernel/time_64.c
> @@ -760,9 +760,7 @@ void setup_sparc64_timer(void)
>                              : /* no outputs */
>                              : "r" (pstate));
>
> -       sevt = this_cpu_ptr(&sparc64_events);
> -
> -       memcpy(sevt, &sparc64_clockevent, sizeof(*sevt));
> +       sevt = memcpy(this_cpu_ptr(&sparc64_events), &sparc64_clockevent, sizeof(*sevt));

IMHO this makes the code harder to read:
  - Only 0.15% of the memcpy() calls in the kernel use the
    memcpy() chaining feature,
  - The line is now longer than the 80-character limit, which is still
    customary for this file.

>         sevt->cpumask = cpumask_of(smp_processor_id());
>
>         clockevents_register_device(sevt);

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds