From patchwork Mon Oct 31 06:19:22 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heng Qi X-Patchwork-Id: 13025410 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4753C38A02 for ; Mon, 31 Oct 2022 06:19:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229561AbiJaGTb (ORCPT ); Mon, 31 Oct 2022 02:19:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229517AbiJaGT3 (ORCPT ); Mon, 31 Oct 2022 02:19:29 -0400 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D183BD6; Sun, 30 Oct 2022 23:19:26 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=14;SR=0;TI=SMTPD_---0VTRRnAt_1667197162; Received: from localhost(mailfrom:hengqi@linux.alibaba.com fp:SMTPD_---0VTRRnAt_1667197162) by smtp.aliyun-inc.com; Mon, 31 Oct 2022 14:19:23 +0800 From: Heng Qi To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , =?utf-8?q?Toke_H=C3=B8iland-J?= =?utf-8?q?=C3=B8rgensen?= , Xuan Zhuo , Heng Qi Subject: [PATCH] veth: Avoid drop packets when xdp_redirect performs Date: Mon, 31 Oct 2022 14:19:22 +0800 Message-Id: <20221031061922.124992-1-hengqi@linux.alibaba.com> X-Mailer: git-send-email 2.19.1.6.gb485710b MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Heng Qi In the current processing logic, when xdp_redirect occurs, it transmits the xdp frame based on napi. If napi of the peer veth is not ready, the veth will drop the packets. This doesn't meet our expectations. In this context, we enable napi of the peer veth automatically when the veth loads the xdp. Then if the veth unloads the xdp, we need to correctly judge whether to disable napi of the peer veth, because the peer veth may have loaded xdp, or even the user has enabled GRO. Signed-off-by: Heng Qi Reviewed-by: Xuan Zhuo --- Previous discussion on this issue is here https://lore.kernel.org/all/87r0yxgxba.fsf@toke.dk/ . drivers/net/veth.c | 88 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 76 insertions(+), 12 deletions(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 466da01ba2e3..105682237a9d 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1119,10 +1119,14 @@ static void veth_disable_xdp_range(struct net_device *dev, int start, int end, static int veth_enable_xdp(struct net_device *dev) { - bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP); struct veth_priv *priv = netdev_priv(dev); + bool napi_already_on; + struct veth_rq *rq; int err, i; + rq = &priv->rq[0]; + napi_already_on = (dev->flags & IFF_UP) && rcu_access_pointer(rq->napi); + if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) { err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on); if (err) @@ -1323,18 +1327,28 @@ static int veth_set_channels(struct net_device *dev, static int veth_open(struct net_device *dev) { - struct veth_priv *priv = netdev_priv(dev); + struct veth_priv *peer_priv, *priv = netdev_priv(dev); struct net_device *peer = rtnl_dereference(priv->peer); + struct veth_rq *peer_rq; int err; if (!peer) return -ENOTCONN; + peer_priv = netdev_priv(peer); + peer_rq = &peer_priv->rq[0]; + if (priv->_xdp_prog) { err = veth_enable_xdp(dev); if (err) return err; - } else if (veth_gro_requested(dev)) { + /* refer to the logic in veth_xdp_set() */ + if (!rtnl_dereference(peer_rq->napi)) { + err = veth_napi_enable(peer); + if (err) + return err; + } + } else if (veth_gro_requested(dev) || peer_priv->_xdp_prog) { err = veth_napi_enable(dev); if (err) return err; @@ -1350,17 +1364,29 @@ static int veth_open(struct net_device *dev) static int veth_close(struct net_device *dev) { - struct veth_priv *priv = netdev_priv(dev); + struct veth_priv *peer_priv, *priv = netdev_priv(dev); struct net_device *peer = rtnl_dereference(priv->peer); + struct veth_rq *peer_rq; netif_carrier_off(dev); - if (peer) - netif_carrier_off(peer); + if (peer) { + peer_priv = netdev_priv(peer); + peer_rq = &peer_priv->rq[0]; + } - if (priv->_xdp_prog) + if (priv->_xdp_prog) { veth_disable_xdp(dev); - else if (veth_gro_requested(dev)) + /* refer to the logic in veth_xdp_set */ + if (peer && rtnl_dereference(peer_rq->napi)) { + if (!veth_gro_requested(peer) && !peer_priv->_xdp_prog) + veth_napi_del(peer); + } + } else if (veth_gro_requested(dev) || (peer && peer_priv->_xdp_prog)) { veth_napi_del(dev); + } + + if (peer) + netif_carrier_off(peer); return 0; } @@ -1470,17 +1496,21 @@ static int veth_set_features(struct net_device *dev, { netdev_features_t changed = features ^ dev->features; struct veth_priv *priv = netdev_priv(dev); + struct veth_rq *rq = &priv->rq[0]; int err; if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog) return 0; if (features & NETIF_F_GRO) { - err = veth_napi_enable(dev); - if (err) - return err; + if (!rtnl_dereference(rq->napi)) { + err = veth_napi_enable(dev); + if (err) + return err; + } } else { - veth_napi_del(dev); + if (rtnl_dereference(rq->napi)) + veth_napi_del(dev); } return 0; } @@ -1512,14 +1542,19 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog, struct netlink_ext_ack *extack) { struct veth_priv *priv = netdev_priv(dev); + struct veth_priv *peer_priv; struct bpf_prog *old_prog; + struct veth_rq *peer_rq; struct net_device *peer; + bool napi_already_off; unsigned int max_mtu; + bool noreq_napi; int err; old_prog = priv->_xdp_prog; priv->_xdp_prog = prog; peer = rtnl_dereference(priv->peer); + peer_priv = netdev_priv(peer); if (prog) { if (!peer) { @@ -1556,6 +1591,24 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog, } } + if (peer && (peer->flags & IFF_UP)) { + peer_rq = &peer_priv->rq[0]; + + /* If the peer hasn't enabled GRO and loaded xdp, + * then we enable napi automatically if its napi + * is not ready. + */ + napi_already_off = !rtnl_dereference(peer_rq->napi); + if (napi_already_off) { + err = veth_napi_enable(peer); + if (err) { + NL_SET_ERR_MSG_MOD(extack, + "Failed to automatically enable napi of peer"); + goto err; + } + } + } + if (!old_prog) { peer->hw_features &= ~NETIF_F_GSO_SOFTWARE; peer->max_mtu = max_mtu; @@ -1570,6 +1623,17 @@ static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog, if (peer) { peer->hw_features |= NETIF_F_GSO_SOFTWARE; peer->max_mtu = ETH_MAX_MTU; + peer_rq = &peer_priv->rq[0]; + + /* If the peer doesn't has its xdp and enabled + * GRO, then we disable napi if its napi is ready; + */ + if (rtnl_dereference(peer_rq->napi)) { + noreq_napi = !veth_gro_requested(peer) && + !peer_priv->_xdp_prog; + if (noreq_napi && (peer->flags & IFF_UP)) + veth_napi_del(peer); + } } } bpf_prog_put(old_prog);