linux-kernel - Re: [PATCH 1/5] blk-throttle: Move three assignments for the variable "ret" in tg_set

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Message-ID: <20170123091510.GA3517@linux-x5ow.site>
Date:   Mon, 23 Jan 2017 10:15:11 +0100
From:   Johannes Thumshirn <jthumshirn@...e.de>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     linux-block@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 1/5] blk-throttle: Move three assignments for the
 variable "ret" in tg_set_max()

On Sun, Jan 22, 2017 at 09:31:29AM +0100, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Sat, 21 Jan 2017 21:23:06 +0100
> 
> A local variable was set to an error code before a concrete error situation
> was detected. Thus move the corresponding assignments into if branches
> to indicate a software failure there.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  block/blk-throttle.c | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)
> 
> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
> index 6f4c96e5f86b..51d112deb02e 100644
> --- a/block/blk-throttle.c
> +++ b/block/blk-throttle.c
> @@ -1327,27 +1327,30 @@ static ssize_t tg_set_max(struct kernfs_open_file *of,
>  			break;
>  		ctx.body += len;
>  
> -		ret = -EINVAL;
>  		p = tok;
>  		strsep(&p, "=");
> -		if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max")))
> +		if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) {
> +			ret = -EINVAL;
>  			goto out_finish;
> +		}

Sorry, I don't like this patch. We know the next error if we encounter one
will be EINVAL until we change it. Your patch doesn't introduce a functual
change and doesn't improve readability, so I don't really see a point for it.

Byte,
	Johannes

-- 
Johannes Thumshirn                                          Storage
jthumshirn@...e.de                                +49 911 74053 689
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