linux-kernel - Re: [PATCH] hwmon: (tmp401) Fix clang -Wimplicit-fallthrough in tmp401_is

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Message-ID: <34038273-3d00-a8e0-d6dc-4317fe56c0d1@roeck-us.net>
Date:   Tue, 16 Nov 2021 08:33:52 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Nathan Chancellor <nathan@...nel.org>,
        Jean Delvare <jdelvare@...e.com>
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev
Subject: Re: [PATCH] hwmon: (tmp401) Fix clang -Wimplicit-fallthrough in
 tmp401_is_visible()

On 11/16/21 7:44 AM, Nathan Chancellor wrote:
> Clang warns:
> 
> drivers/hwmon/tmp401.c:526:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough]
>          default:
>          ^
> drivers/hwmon/tmp401.c:526:2: note: insert 'break;' to avoid fall-through
>          default:
>          ^
>          break;
> 1 error generated.
> 
> Clang is a little more pedantic than GCC, which does not warn when
> falling through to a case that is just break or return. Clang's version
> is more in line with the kernel's own stance in deprecated.rst, which
> states that all switch/case blocks must end in either break,
> fallthrough, continue, goto, or return. Add the missing break to silence
> the warning.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1505
> Signed-off-by: Nathan Chancellor <nathan@...nel.org>
> ---
> 
> Feel free to squash this into the offending commit.

Done, thanks a lot for the feedback.

Guenter

> 
>   drivers/hwmon/tmp401.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/hwmon/tmp401.c b/drivers/hwmon/tmp401.c
> index f7b6a2c4fbcf..b86d9df7105d 100644
> --- a/drivers/hwmon/tmp401.c
> +++ b/drivers/hwmon/tmp401.c
> @@ -523,6 +523,7 @@ static umode_t tmp401_is_visible(const void *data, enum hwmon_sensor_types type,
>   		default:
>   			break;
>   		}
> +		break;
>   	default:
>   		break;
>   	}
> 
> base-commit: 82b520da9134a594eb9816759ed66ba6ef44888e
>