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=-2.6 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=no 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 C2D6AC352A2 for ; Wed, 5 Feb 2020 12:06:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A5554217BA for ; Wed, 5 Feb 2020 12:06:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727458AbgBEMG1 (ORCPT ); Wed, 5 Feb 2020 07:06:27 -0500 Received: from mga14.intel.com ([192.55.52.115]:56042 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726810AbgBEMG1 (ORCPT ); Wed, 5 Feb 2020 07:06:27 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2020 04:06:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,405,1574150400"; d="scan'208";a="254742591" Received: from ranger.igk.intel.com ([10.102.21.164]) by fmsmga004.fm.intel.com with ESMTP; 05 Feb 2020 04:06:24 -0800 From: Maciej Fijalkowski To: ast@kernel.org, daniel@iogearbox.net Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, bjorn.topel@intel.com, magnus.karlsson@intel.com, maximmi@mellanox.com Subject: [PATCH bpf 0/3] XSK related fixes Date: Wed, 5 Feb 2020 05:58:31 +0100 Message-Id: <20200205045834.56795-1-maciej.fijalkowski@intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Cameron reported [0] that on fresh bpf-next he could not run multiple xdpsock instances in Tx-only mode on single network interface with i40e driver. Turns out that Maxim's series [1] which was adding RCU protection around ndo_xsk_wakeup added check against the __I40E_CONFIG_BUSY being set on pf->state within i40e_xsk_wakeup() - if it's set, return -ENETDOWN. Since this bit is set per PF when UMEM is being enabled/disabled, the situation Cameron stumbled upon was that when he launched second xdpsock instance, second UMEM was being registered, hence set __I40E_CONFIG_BUSY which is now observed by first xdpsock and therefore xdpsock's kick_tx() gets -ENETDOWN as errno. -ENETDOWN currently is not allowed in kick_tx(), so we were exiting the first application. Such exit means also XDP program being unloaded and its dedicated resources, which caused an -ENXIO being return in the second xdpsock instance. Let's fix the issue from both sides - protect ourselves from future xdpsock crashes by allowing for -ENETDOWN errno being set in kick_tx() (patch 3) and from driver side, return -EAGAIN for the case where PF is busy (patch 1). Remove also doubled variable from xdpsock_user.c (patch 2). Note that ixgbe seems not to be affected since UMEM registration sets the busy/disable bit per ring, not per PF. Thanks! Maciej [0]: https://www.spinics.net/lists/xdp-newbies/msg01558.html [1]: https://lore.kernel.org/netdev/20191217162023.16011-1-maximmi@mellanox.com/ Maciej Fijalkowski (3): i40e: Relax i40e_xsk_wakeup's return value when PF is busy samples: bpf: drop doubled variable declaration in xdpsock samples: bpf: allow for -ENETDOWN in xdpsock drivers/net/ethernet/intel/i40e/i40e_xsk.c | 2 +- samples/bpf/xdpsock_user.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) -- 2.20.1