linux-kernel - Re: [PATCH] printk: remove obsolete dead assignment

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Date:   Mon, 30 Nov 2020 16:37:33 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Lukas Bulwahn <lukas.bulwahn@...il.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        John Ogness <john.ogness@...utronix.de>,
        Nathan Chancellor <natechancellor@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        kernel-janitors@...r.kernel.org, linux-safety@...ts.elisa.tech
Subject: Re: [PATCH] printk: remove obsolete dead assignment

On Mon 2020-11-30 13:49:15, Lukas Bulwahn wrote:
> Commit 849f3127bb46 ("switch /dev/kmsg to ->write_iter()") refactored
> devkmsg_write() and left over a dead assignment on the variable 'len'.
> 
> Hence, make clang-analyzer warns:
> 
>   kernel/printk/printk.c:744:4: warning: Value stored to 'len' is never read
>     [clang-analyzer-deadcode.DeadStores]
>                           len -= endp - line;
>                           ^
> 
> Simply remove this obsolete dead assignment here.
> 
> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@...il.com>
> ---
> applies cleanly on current master and next-20201130
> 
> Petr, please pick this minor non-urgent clean-up patch.
> 
>  kernel/printk/printk.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index f279d4fbd9dd..6e4e38b7cd91 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -741,7 +741,6 @@ static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from)
>  			if (LOG_FACILITY(u) != 0)
>  				facility = LOG_FACILITY(u);
>  			endp++;
> -			len -= endp - line;
>  			line = endp;
>  		}
>  	}

Yup, it was used to write the trailing '\0'. But it is done earlier
now. So, it is not longer needed.

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr

PS: I'll give it few days just in case anyone else would want to
review it. I'll push it then unless anyone complains.