From patchwork Fri Mar 26 14:29:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Loftus, Ciara" X-Patchwork-Id: 409968 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 9A139C433E4 for ; Fri, 26 Mar 2021 15:02:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7688B61A18 for ; Fri, 26 Mar 2021 15:02:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230316AbhCZPCc (ORCPT ); Fri, 26 Mar 2021 11:02:32 -0400 Received: from mga14.intel.com ([192.55.52.115]:38778 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230250AbhCZPBs (ORCPT ); Fri, 26 Mar 2021 11:01:48 -0400 IronPort-SDR: 5YGF4CxWIDD67FDXaKRNzGdLhuUSA7bqYp3VSb2nanAc9DH7bWYVhzD/4h0LiU7v+gQwmNDgcE rhFgiP7HWFIw== X-IronPort-AV: E=McAfee;i="6000,8403,9935"; a="190602933" X-IronPort-AV: E=Sophos;i="5.81,280,1610438400"; d="scan'208";a="190602933" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Mar 2021 08:01:23 -0700 IronPort-SDR: yAoKqxBmFEKObLeIIpvkh+lc2eZp8OLCeB00j1WB4fG5/sW0p6C7QTQzKLwpgJVVnJk4M9datT +2yW05nhH3Gw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,280,1610438400"; d="scan'208";a="382668354" Received: from silpixa00399839.ir.intel.com (HELO localhost.localdomain) ([10.237.222.142]) by fmsmga007.fm.intel.com with ESMTP; 26 Mar 2021 08:01:20 -0700 From: Ciara Loftus To: netdev@vger.kernel.org, bpf@vger.kernel.org, magnus.karlsson@intel.com, bjorn@kernel.org, magnus.karlsson@gmail.com Cc: Ciara Loftus Subject: [PATCH v2 bpf 3/3] libbpf: ignore return values of setsockopt for XDP rings. Date: Fri, 26 Mar 2021 14:29:46 +0000 Message-Id: <20210326142946.5263-4-ciara.loftus@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210326142946.5263-1-ciara.loftus@intel.com> References: <20210326142946.5263-1-ciara.loftus@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org During xsk_socket__create the XDP_RX_RING and XDP_TX_RING setsockopts are called to create the rx and tx rings for the AF_XDP socket. If the ring has already been set up, the setsockopt will return an error. However, in the event of a failure during xsk_socket__create(_shared) after the rings have been set up, the user may wish to retry the socket creation using these pre-existing rings. In this case we can ignore the error returned by the setsockopts. If there is a true error, the subsequent call to mmap() will catch it. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Acked-by: Magnus Karlsson Signed-off-by: Ciara Loftus --- tools/lib/bpf/xsk.c | 34 ++++++++++++++++------------------ 1 file changed, 16 insertions(+), 18 deletions(-) diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index d4991ddff05a..cfc4abf505c3 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -900,24 +900,22 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr, } xsk->ctx = ctx; - if (rx) { - err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING, - &xsk->config.rx_size, - sizeof(xsk->config.rx_size)); - if (err) { - err = -errno; - goto out_put_ctx; - } - } - if (tx) { - err = setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING, - &xsk->config.tx_size, - sizeof(xsk->config.tx_size)); - if (err) { - err = -errno; - goto out_put_ctx; - } - } + /* The return values of these setsockopt calls are intentionally not checked. + * If the ring has already been set up setsockopt will return an error. However, + * this scenario is acceptable as the user may be retrying the socket creation + * with rings which were set up in a previous but ultimately unsuccessful call + * to xsk_socket__create(_shared). The call later to mmap() will fail if there + * is a real issue and we handle that return value appropriately there. + */ + if (rx) + setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING, + &xsk->config.rx_size, + sizeof(xsk->config.rx_size)); + + if (tx) + setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING, + &xsk->config.tx_size, + sizeof(xsk->config.tx_size)); err = xsk_get_mmap_offsets(xsk->fd, &off); if (err) {