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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 9283DC4321E for ; Fri, 7 Sep 2018 03:24:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 522D920857 for ; Fri, 7 Sep 2018 03:24:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 522D920857 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726682AbeIGICx (ORCPT ); Fri, 7 Sep 2018 04:02:53 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40308 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725785AbeIGICx (ORCPT ); Fri, 7 Sep 2018 04:02:53 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A40FC738F0; Fri, 7 Sep 2018 03:24:09 +0000 (UTC) Received: from [10.72.12.125] (ovpn-12-125.pek2.redhat.com [10.72.12.125]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6B38A10F1BFF; Fri, 7 Sep 2018 03:24:05 +0000 (UTC) Subject: Re: [PATCH net-next 05/11] tuntap: tweak on the path of non-xdp case in tun_build_skb() To: "Michael S. Tsirkin" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org References: <20180906040526.22518-1-jasowang@redhat.com> <20180906040526.22518-6-jasowang@redhat.com> <20180906131509-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <8a5b5db7-ce53-7dc5-7410-0b6d51b5bf10@redhat.com> Date: Fri, 7 Sep 2018 11:24:02 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180906131509-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 07 Sep 2018 03:24:09 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 07 Sep 2018 03:24:09 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jasowang@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年09月07日 01:16, Michael S. Tsirkin wrote: > On Thu, Sep 06, 2018 at 12:05:20PM +0800, Jason Wang wrote: >> If we're sure not to go native XDP, there's no need for several things >> like bh and rcu stuffs. >> >> Signed-off-by: Jason Wang > True... > >> --- >> drivers/net/tun.c | 9 ++++++--- >> 1 file changed, 6 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> index f8cdcfa392c3..389aa0727cc6 100644 >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1675,10 +1675,12 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> * of xdp_prog above, this should be rare and for simplicity >> * we do XDP on skb in case the headroom is not enough. >> */ >> - if (hdr->gso_type || !xdp_prog) >> + if (hdr->gso_type || !xdp_prog) { >> *skb_xdp = 1; >> - else >> - *skb_xdp = 0; >> + goto build; >> + } >> + >> + *skb_xdp = 0; >> >> local_bh_disable(); >> rcu_read_lock(); >> @@ -1724,6 +1726,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> rcu_read_unlock(); >> local_bh_enable(); >> >> +build: > But this is spaghetti code. Please just put common > code into functions and call them, don't goto. Ok, will do this. Thanks > >> skb = build_skb(buf, buflen); >> if (!skb) { >> skb = ERR_PTR(-ENOMEM); >> -- >> 2.17.1