From patchwork Tue Jan 29 14:03:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Magnus Karlsson X-Patchwork-Id: 1032793 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43ppBm2Bp1z9sCX for ; Wed, 30 Jan 2019 01:04:00 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727945AbfA2OD7 (ORCPT ); Tue, 29 Jan 2019 09:03:59 -0500 Received: from mga09.intel.com ([134.134.136.24]:7155 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725846AbfA2OD6 (ORCPT ); Tue, 29 Jan 2019 09:03:58 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Jan 2019 06:03:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,537,1539673200"; d="scan'208";a="270823493" Received: from mkarlsso-mobl.ger.corp.intel.com (HELO VM.isw.intel.com) ([10.103.211.42]) by orsmga004.jf.intel.com with ESMTP; 29 Jan 2019 06:03:57 -0800 From: Magnus Karlsson To: magnus.karlsson@intel.com, bjorn.topel@intel.com, intel-wired-lan@lists.osuosl.org Cc: netdev@vger.kernel.org Subject: [PATCH net] ixgbe: fix potential RX buffer starvation for AF_XDP Date: Tue, 29 Jan 2019 15:03:50 +0100 Message-Id: <1548770630-16189-1-git-send-email-magnus.karlsson@intel.com> X-Mailer: git-send-email 2.7.4 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When the RX rings are created they are also populated with buffers so that packets can be received. Usually these are kernel buffers, but for AF_XDP in zero-copy mode, these are user-space buffers and in this case the application might not have sent down any buffers to the driver at this point. And if no buffers are allocated at ring creation time, no packets can be received and no interupts will be generated so the napi poll function that allocates buffers to the rings will never get executed. To recitfy this, we kick the NAPI context of any queue with an attached AF_XDP zero-copy socket in two places in the code. Once after an XDP program has loaded and once after the umem is registered. This take care of both cases: XDP program gets loaded first then AF_XDP socket is created, and the reverse, AF_XDP socket is created first, then XDP program is loaded. Fixes: d0bcacd0a130 ("ixgbe: add AF_XDP zero-copy Rx support") Signed-off-by: Magnus Karlsson Tested-by: Andrew Bowers --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 12 +++++++++++- drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 12 ++++++++++-- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index daff818..017c930 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -10225,6 +10225,7 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) int i, frame_size = dev->mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN; struct ixgbe_adapter *adapter = netdev_priv(dev); struct bpf_prog *old_prog; + bool need_reset; if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) return -EINVAL; @@ -10247,9 +10248,10 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) return -ENOMEM; old_prog = xchg(&adapter->xdp_prog, prog); + need_reset = (!!prog != !!old_prog); /* If transitioning XDP modes reconfigure rings */ - if (!!prog != !!old_prog) { + if (need_reset) { int err = ixgbe_setup_tc(dev, adapter->hw_tcs); if (err) { @@ -10265,6 +10267,14 @@ static int ixgbe_xdp_setup(struct net_device *dev, struct bpf_prog *prog) if (old_prog) bpf_prog_put(old_prog); + /* Kick start the NAPI context if there is an AF_XDP socket open + * on that queue id. This so that receiving will start. + */ + if (need_reset && prog) + for (i = 0; i < adapter->num_rx_queues; i++) + if (adapter->xdp_ring[i]->xsk_umem) + (void)ixgbe_xsk_async_xmit(adapter->netdev, i); + return 0; } diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c index 65c3e2c..654ae92 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c @@ -144,11 +144,19 @@ static int ixgbe_xsk_umem_enable(struct ixgbe_adapter *adapter, ixgbe_txrx_ring_disable(adapter, qid); err = ixgbe_add_xsk_umem(adapter, umem, qid); + if (err) + return err; - if (if_running) + if (if_running) { ixgbe_txrx_ring_enable(adapter, qid); - return err; + /* Kick start the NAPI context so that receiving will start */ + err = ixgbe_xsk_async_xmit(adapter->netdev, qid); + if (err) + return err; + } + + return 0; } static int ixgbe_xsk_umem_disable(struct ixgbe_adapter *adapter, u16 qid)