From patchwork Mon May 21 09:04:29 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 10414393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 637AA600CC for ; Mon, 21 May 2018 09:07:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 559A2286BA for ; Mon, 21 May 2018 09:07:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 498E2287C3; Mon, 21 May 2018 09:07:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F41D3286BA for ; Mon, 21 May 2018 09:07:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752699AbeEUJFS (ORCPT ); Mon, 21 May 2018 05:05:18 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:54680 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752670AbeEUJFP (ORCPT ); Mon, 21 May 2018 05:05:15 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9C96E400E9A7; Mon, 21 May 2018 09:05:14 +0000 (UTC) Received: from jason-ThinkPad-T450s.redhat.com (ovpn-12-30.pek2.redhat.com [10.72.12.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9C04F4AF1; Mon, 21 May 2018 09:05:11 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH net-next 08/12] tuntap: tweak on the path of non-xdp case in tun_build_skb() Date: Mon, 21 May 2018 17:04:29 +0800 Message-Id: <1526893473-20128-9-git-send-email-jasowang@redhat.com> In-Reply-To: <1526893473-20128-1-git-send-email-jasowang@redhat.com> References: <1526893473-20128-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Mon, 21 May 2018 09:05:14 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Mon, 21 May 2018 09:05:14 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jasowang@redhat.com' RCPT:'' Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If we're sure not to go native XDP, there's no need for several things like touching preemption counter and rcu stuffs. Signed-off-by: Jason Wang --- 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 f6e0f96..ed04291 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1645,10 +1645,12 @@ 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; preempt_disable(); rcu_read_lock(); @@ -1695,6 +1697,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, rcu_read_unlock(); preempt_enable(); +build: skb = build_skb(buf, buflen); if (!skb) { skb = ERR_PTR(-ENOMEM);