linux-kernel - Re: [PATCH v1 1/1] kasan: Replace strreplace() with strchrnul()

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Message-ID: <CAG_fn=WjLDsnUPKFwF8XJiyqYP6M+Q9ZqUweRPzPT3dW0i_E+A@mail.gmail.com>
Date:   Wed, 28 Jun 2023 17:39:26 +0200
From:   Alexander Potapenko <glider@...gle.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        kasan-dev@...glegroups.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>
Subject: Re: [PATCH v1 1/1] kasan: Replace strreplace() with strchrnul()

On Wed, Jun 28, 2023 at 5:34 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> We don't need to traverse over the entire string and replace
> occurrences of a character with '\0'. The first match will
> suffice. Hence, replace strreplace() with strchrnul().
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  mm/kasan/report_generic.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
> index 51a1e8a8877f..63a34eac4a8c 100644
> --- a/mm/kasan/report_generic.c
> +++ b/mm/kasan/report_generic.c
> @@ -264,6 +264,7 @@ static void print_decoded_frame_descr(const char *frame_descr)
>         while (num_objects--) {
>                 unsigned long offset;
>                 unsigned long size;
> +               char *p;
>
>                 /* access offset */
>                 if (!tokenize_frame_descr(&frame_descr, token, sizeof(token),
> @@ -282,7 +283,7 @@ static void print_decoded_frame_descr(const char *frame_descr)
>                         return;
>
>                 /* Strip line number; without filename it's not very helpful. */
> -               strreplace(token, ':', '\0');
> +               p[strchrnul(token, ':') - token] = '\0';

Why not just
   *(strchrnul(token, ':')) = '\0';
?