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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Wed, 23 Dec 2020 15:33:36 +0900
Message-ID: <CAK7LNASGT9fw59-s9Tz-cA7zNt6TVdPdB5WMSea55U3qETDphw@mail.gmail.com>
Subject: Re: [PATCH] sh: check return code of request_irq
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Paul Mundt <lethal@linux-sh.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Linux-sh list <linux-sh@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Wed, Dec 23, 2020 at 5:54 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> request_irq is marked __must_check, but the call in shx3_prepare_cpus
> has a void return type, so it can't propagate failure to the caller.
> Follow cues from hexagon and just print an error.
>
> Fixes: c7936b9abcf5 ("sh: smp: Hook in to the generic IPI handler for SH-X3 SMP.")
> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>


Thanks for the patch, Nick.

I just wondered if there was a better error handling than
printing the message. I have no idea if the system will
boot up correctly when the request_irq() fails here.

I hope the maintainers will suggest something, if any.


> ---
>  arch/sh/kernel/cpu/sh4a/smp-shx3.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/sh/kernel/cpu/sh4a/smp-shx3.c b/arch/sh/kernel/cpu/sh4a/smp-shx3.c
> index f8a2bec0f260..1261dc7b84e8 100644
> --- a/arch/sh/kernel/cpu/sh4a/smp-shx3.c
> +++ b/arch/sh/kernel/cpu/sh4a/smp-shx3.c
> @@ -73,8 +73,9 @@ static void shx3_prepare_cpus(unsigned int max_cpus)
>         BUILD_BUG_ON(SMP_MSG_NR >= 8);
>
>         for (i = 0; i < SMP_MSG_NR; i++)
> -               request_irq(104 + i, ipi_interrupt_handler,
> -                           IRQF_PERCPU, "IPI", (void *)(long)i);
> +               if (request_irq(104 + i, ipi_interrupt_handler,
> +                           IRQF_PERCPU, "IPI", (void *)(long)i))
> +                       pr_err("Failed to request irq %d\n", i);
>
>         for (i = 0; i < max_cpus; i++)
>                 set_cpu_present(i, true);
> --
> 2.29.2.729.g45daf8777d-goog
>


-- 
Best Regards
Masahiro Yamada