From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE34BC4360F for ; Fri, 5 Apr 2019 06:47:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 762B3206DF for ; Fri, 5 Apr 2019 06:47:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="TfPkypfM"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="FQyFVAjg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729783AbfDEGrL (ORCPT ); Fri, 5 Apr 2019 02:47:11 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:53892 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbfDEGrL (ORCPT ); Fri, 5 Apr 2019 02:47:11 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 75FB2609F3; Fri, 5 Apr 2019 06:47:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1554446829; bh=GW7WCqZ/kt/rcIsbdZNdWqoDeu0IwQVDlnNoiYbbT7c=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=TfPkypfM0c7Pna0sgW/vH2h2g+KXgl7bA/KSe8Ob+XPEeBjHNkuOYwnTJWWrRBtU/ Rakw+XO1ixl0FNh/f6CiSj4NWz2NcIriGoHJ0s2m7zqVRh2rmkqk0RBUhaHrln+yCv hlmv2KkszjB1pX4BgJ01CHp2dk99MVi8QP9hUAQQ= Received: from [10.204.79.83] (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mojha@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 67D016087A; Fri, 5 Apr 2019 06:47:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1554446828; bh=GW7WCqZ/kt/rcIsbdZNdWqoDeu0IwQVDlnNoiYbbT7c=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=FQyFVAjgf40UU4imQ/DuAFDjziMBSOA0r3Yj8xzXvqiC932+wpddHdAAZ1obXb9yf 8RakB2buW0IG2ro7QmoAkyE6JtXdXYs1Ghfu8Vq57Tgc58aUPVj55oaGSb79i2acqh 63YWi5wXHDTTmQaow7xqGKhoTV6FZzrHFDOTxlbs= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 67D016087A Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=mojha@codeaurora.org Subject: Re: [PATCH] tcp: remove redundant check on tskb To: Colin King , Eric Dumazet , "David S . Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , netdev@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190404144603.27682-1-colin.king@canonical.com> From: Mukesh Ojha Message-ID: Date: Fri, 5 Apr 2019 12:17:04 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190404144603.27682-1-colin.king@canonical.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/4/2019 8:16 PM, Colin King wrote: > From: Colin Ian King > > 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 Reviewed-by: Mukesh Ojha Cheers, -Mukesh > --- > net/ipv4/tcp_output.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > index e265d1aeeb66..32061928b054 100644 > --- a/net/ipv4/tcp_output.c > +++ b/net/ipv4/tcp_output.c > @@ -3088,7 +3088,6 @@ void tcp_send_fin(struct sock *sk) > tskb = skb_rb_last(&sk->tcp_rtx_queue); > > if (tskb) { > -coalesce: > TCP_SKB_CB(tskb)->tcp_flags |= TCPHDR_FIN; > TCP_SKB_CB(tskb)->end_seq++; > tp->write_seq++; > @@ -3104,11 +3103,9 @@ void tcp_send_fin(struct sock *sk) > } > } else { > skb = alloc_skb_fclone(MAX_TCP_HEADER, sk->sk_allocation); > - if (unlikely(!skb)) { > - if (tskb) > - goto coalesce; > + if (unlikely(!skb)) > return; > - } > + > INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); > skb_reserve(skb, MAX_TCP_HEADER); > sk_forced_mem_schedule(sk, skb->truesize);