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 B7062C433F5 for ; Fri, 7 Sep 2018 03:29:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61624205F4 for ; Fri, 7 Sep 2018 03:29:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 61624205F4 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 S1727413AbeIGII3 (ORCPT ); Fri, 7 Sep 2018 04:08:29 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38534 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725999AbeIGII3 (ORCPT ); Fri, 7 Sep 2018 04:08:29 -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 C0283401EF3D; Fri, 7 Sep 2018 03:29:42 +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 622C010F1BFF; Fri, 7 Sep 2018 03:29:37 +0000 (UTC) Subject: Re: [PATCH net-next 06/11] tuntap: split out XDP logic 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> <20180906040526.22518-7-jasowang@redhat.com> <20180906131703-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <84ae17c1-f34b-610d-a5a1-ba8dce1732f3@redhat.com> Date: Fri, 7 Sep 2018 11:29:34 +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: <20180906131703-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 [10.11.55.5]); Fri, 07 Sep 2018 03:29:42 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 07 Sep 2018 03:29:42 +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 01:21, Michael S. Tsirkin wrote: > On Thu, Sep 06, 2018 at 12:05:21PM +0800, Jason Wang wrote: >> This patch split out XDP logic into a single function. This make it to >> be reused by XDP batching path in the following patch. >> >> Signed-off-by: Jason Wang >> --- >> drivers/net/tun.c | 84 ++++++++++++++++++++++++++++------------------- >> 1 file changed, 51 insertions(+), 33 deletions(-) >> >> diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> index 389aa0727cc6..21b125020b3b 100644 >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, >> return true; >> } >> >> +static u32 tun_do_xdp(struct tun_struct *tun, >> + struct tun_file *tfile, >> + struct bpf_prog *xdp_prog, >> + struct xdp_buff *xdp, >> + int *err) >> +{ >> + u32 act = bpf_prog_run_xdp(xdp_prog, xdp); >> + >> + switch (act) { >> + case XDP_REDIRECT: >> + *err = xdp_do_redirect(tun->dev, xdp, xdp_prog); >> + xdp_do_flush_map(); >> + if (*err) >> + break; >> + goto out; >> + case XDP_TX: >> + *err = tun_xdp_tx(tun->dev, xdp); >> + if (*err < 0) >> + break; >> + *err = 0; >> + goto out; >> + case XDP_PASS: >> + goto out; > Do we need goto? why not just return? I don't see any difference. > >> + default: >> + bpf_warn_invalid_xdp_action(act); >> + /* fall through */ >> + case XDP_ABORTED: >> + trace_xdp_exception(tun->dev, xdp_prog, act); >> + /* fall through */ >> + case XDP_DROP: >> + break; >> + } >> + >> + put_page(virt_to_head_page(xdp->data_hard_start)); > put here because caller does get_page :( Not pretty. > I'd move this out to the caller. Then we need a switch in the caller, not sure it's better. > >> +out: >> + return act; > How about combining err and act? err is < 0 XDP_PASS is > 0. > No need for pointers then. Ok. > >> +} >> + >> static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> struct tun_file *tfile, >> struct iov_iter *from, >> @@ -1645,10 +1683,10 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> struct sk_buff *skb = NULL; >> struct bpf_prog *xdp_prog; >> int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); >> - unsigned int delta = 0; >> char *buf; >> size_t copied; >> - int err, pad = TUN_RX_PAD; >> + int pad = TUN_RX_PAD; >> + int err = 0; >> >> rcu_read_lock(); >> xdp_prog = rcu_dereference(tun->xdp_prog); >> @@ -1685,9 +1723,8 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> local_bh_disable(); >> rcu_read_lock(); >> xdp_prog = rcu_dereference(tun->xdp_prog); >> - if (xdp_prog && !*skb_xdp) { >> + if (xdp_prog) { >> struct xdp_buff xdp; >> - void *orig_data; >> u32 act; >> >> xdp.data_hard_start = buf; >> @@ -1695,33 +1732,14 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> xdp_set_data_meta_invalid(&xdp); >> xdp.data_end = xdp.data + len; >> xdp.rxq = &tfile->xdp_rxq; >> - orig_data = xdp.data; >> - act = bpf_prog_run_xdp(xdp_prog, &xdp); >> - >> - switch (act) { >> - case XDP_REDIRECT: >> - err = xdp_do_redirect(tun->dev, &xdp, xdp_prog); >> - xdp_do_flush_map(); >> - if (err) >> - goto err_xdp; >> - goto out; >> - case XDP_TX: >> - if (tun_xdp_tx(tun->dev, &xdp) < 0) >> - goto err_xdp; >> - goto out; >> - case XDP_PASS: >> - delta = orig_data - xdp.data; >> - len = xdp.data_end - xdp.data; >> - break; >> - default: >> - bpf_warn_invalid_xdp_action(act); >> - /* fall through */ >> - case XDP_ABORTED: >> - trace_xdp_exception(tun->dev, xdp_prog, act); >> - /* fall through */ >> - case XDP_DROP: >> + act = tun_do_xdp(tun, tfile, xdp_prog, &xdp, &err); >> + if (err) >> goto err_xdp; >> - } >> + if (act != XDP_PASS) >> + goto out; > likely? It depends on the XDP program, so I tend not to use it. > >> + >> + pad = xdp.data - xdp.data_hard_start; >> + len = xdp.data_end - xdp.data; >> } >> rcu_read_unlock(); >> local_bh_enable(); >> @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> build: >> skb = build_skb(buf, buflen); >> if (!skb) { >> + put_page(alloc_frag->page); >> skb = ERR_PTR(-ENOMEM); >> goto out; >> } >> >> - skb_reserve(skb, pad - delta); >> + skb_reserve(skb, pad); >> skb_put(skb, len); >> >> return skb; >> >> err_xdp: >> - alloc_frag->offset -= buflen; >> - put_page(alloc_frag->page); >> + this_cpu_inc(tun->pcpu_stats->rx_dropped); > > This fixes bug in previous patch which dropped it. OK :) Yes, but let me move this to the buggy patch. Thanks >> out: >> rcu_read_unlock(); >> local_bh_enable(); >> -- >> 2.17.1