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 F04BEC433F5 for ; Thu, 6 Sep 2018 17:21:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8667B2075B for ; Thu, 6 Sep 2018 17:21:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8667B2075B 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 S1728315AbeIFV6Q (ORCPT ); Thu, 6 Sep 2018 17:58:16 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34456 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726541AbeIFV6Q (ORCPT ); Thu, 6 Sep 2018 17:58:16 -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 280378077104; Thu, 6 Sep 2018 17:21:47 +0000 (UTC) Received: from redhat.com (ovpn-120-232.rdu2.redhat.com [10.10.120.232]) by smtp.corp.redhat.com (Postfix) with SMTP id CA13F10073DD; Thu, 6 Sep 2018 17:21:46 +0000 (UTC) Date: Thu, 6 Sep 2018 13:21:46 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH net-next 06/11] tuntap: split out XDP logic Message-ID: <20180906131703-mutt-send-email-mst@kernel.org> References: <20180906040526.22518-1-jasowang@redhat.com> <20180906040526.22518-7-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180906040526.22518-7-jasowang@redhat.com> 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 [10.11.55.8]); Thu, 06 Sep 2018 17:21:47 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 06 Sep 2018 17:21:47 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mst@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? > + 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. > +out: > + return act; How about combining err and act? err is < 0 XDP_PASS is > 0. No need for pointers then. > +} > + > 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? > + > + 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 :) > out: > rcu_read_unlock(); > local_bh_enable(); > -- > 2.17.1