linux-kernel - Re: [PATCH] tcp: remove redundant check on tskb

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Date:   Thu, 4 Apr 2019 18:05:09 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Eric Dumazet <edumazet@...gle.com>,
        "David S . Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        netdev@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tcp: remove redundant check on tskb

On Thu, Apr 04, 2019 at 03:46:03PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The non-null check on tskb is always false because it is in an else
> path of a check on tskb and hence tskb is null in this code block.
> This is check is therefore redundant and can be removed as well
> as the label coalesc.
> 
> if (tsbk) {
>         ...
> } else {
>         ...
>         if (unlikely(!skb)) {
>                 if (tskb)       /* can never be true, redundant code */
>                         goto coalesc;
>                 return;
>         }
> }
> 
> Addresses-Coverity: ("Logically dead code")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

This was fallout from commit 75c119afe14f ("tcp: implement rb-tree based
retransmit queue").

regards,
dan carpenter