From patchwork Fri Dec 18 13:45:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Magnus Karlsson X-Patchwork-Id: 346199 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 A87EFC2D0E4 for ; Fri, 18 Dec 2020 13:46:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7200F23A9C for ; Fri, 18 Dec 2020 13:46:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726719AbgLRNqd (ORCPT ); Fri, 18 Dec 2020 08:46:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726540AbgLRNqd (ORCPT ); Fri, 18 Dec 2020 08:46:33 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E5E6BC06138C; Fri, 18 Dec 2020 05:45:52 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id s21so1549847pfu.13; Fri, 18 Dec 2020 05:45:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=puW3DbJ+oWMyv153IUMmlQ4G7FVM7E3yY+4xe0UfzkA=; b=FCJ8Yw15ZeymnEvZv6tabs1xv8nR/E4Nn9pAqHXavlPiofDnnrrMeO6QeDW5S+S0nn NpbWrcIa/QtJA989zng4CDLJgGYc+K5kn/t/nkPaYJl/phfTt89vv7OoyjXYbqmyR6Z6 hYGq89/p3/3SBZF9tD23EeI/Q3/tnePky6QjDrWLBiLg3o8YRzYSMahtdUOGVvFW3ATu 17+W5sd1/2rQxXq+tG+tfyyrWQqFQhWeRPUUSLaO7I4aE7XYkyAV7s9MAfCJo4gCebrp K8/ChM2vAA7T8jrSMpgmYe0f/uGYFc+3IHYAYEPOysCmUiQvP1gHtxanxBLT3CtFkkb+ K4qQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=puW3DbJ+oWMyv153IUMmlQ4G7FVM7E3yY+4xe0UfzkA=; b=jTjQhHgjSvLgIOc8CBFJDkv8fIjjCwqkBYHB8SckfPLxjlSzIteAZYZjeAp7XaeIjs iwnvuc/U30XIIvyUT/sFd42Rxv373/aQl3t67jCTP6pEETjAQP2E4YKH2DRlJJc0FFuJ u0+cCLfe8255xxDZ55ieFeXFIfixw10fBw3vfJ7ZhQ9d170i7LOEa5fDMJJ5lVEcueSJ /Y45bva+XYFVA82qAEJ4J2U4hZBRPmVfUQLSLTQh7aH+oSesFNGTUxyvnZic6Dpa8ez6 +ZkpgZCXUWJL6zUSMsO3leTMbtWliI/kQwjueQdhqctb7bS4n0sC5bcpweJlLvClGthA aKbA== X-Gm-Message-State: AOAM532vtA1yzN1DTs7suE3vz7Ug/Ji6sA4DtBfBj15iUIpiRBLAERcx 3IXsPo4e4tShEKMkoYQ6Jn8= X-Google-Smtp-Source: ABdhPJz0tU/9pyS2OnRIpSGN2I6ROVPelmMlTbNo3XMMNncgzYMcCwm7WkPPNN3mct/m5pLZHd/8Fw== X-Received: by 2002:aa7:84d5:0:b029:19d:da20:73fe with SMTP id x21-20020aa784d50000b029019dda2073femr4364071pfn.16.1608299152520; Fri, 18 Dec 2020 05:45:52 -0800 (PST) Received: from VM.ger.corp.intel.com ([192.55.54.44]) by smtp.gmail.com with ESMTPSA id r185sm9075906pfc.53.2020.12.18.05.45.48 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 Dec 2020 05:45:52 -0800 (PST) From: Magnus Karlsson To: magnus.karlsson@intel.com, bjorn.topel@intel.com, ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, jonathan.lemon@gmail.com Cc: bpf@vger.kernel.org, A.Zema@falconvsystems.com, maciej.fijalkowski@intel.com, maciejromanfijalkowski@gmail.com, Xuan Zhuo Subject: [PATCH bpf v2 2/2] xsk: rollback reservation at NETDEV_TX_BUSY Date: Fri, 18 Dec 2020 14:45:25 +0100 Message-Id: <20201218134525.13119-3-magnus.karlsson@gmail.com> X-Mailer: git-send-email 2.29.0 In-Reply-To: <20201218134525.13119-1-magnus.karlsson@gmail.com> References: <20201218134525.13119-1-magnus.karlsson@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Magnus Karlsson Rollback the reservation in the completion ring when we get a NETDEV_TX_BUSY. When this error is received from the driver, we are supposed to let the user application retry the transmit again. And in order to do this, we need to roll back the failed send so it can be retried. Unfortunately, we did not cancel the reservation we had made in the completion ring. By not doing this, we actually make the completion ring one entry smaller per NETDEV_TX_BUSY error we get, and after enough of these errors the completion ring will be of size zero and transmit will stop working. Fix this by cancelling the reservation when we get a NETDEV_TX_BUSY error. Fixes: 642e450b6b59 ("xsk: Do not discard packet when NETDEV_TX_BUSY") Signed-off-by: Magnus Karlsson Reported-by: Xuan Zhuo Acked-by: Björn Töpel --- net/xdp/xsk.c | 3 +++ net/xdp/xsk_queue.h | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index d531f9cd0de6..8037b04a9edd 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -487,6 +487,9 @@ static int xsk_generic_xmit(struct sock *sk) if (err == NETDEV_TX_BUSY) { /* Tell user-space to retry the send */ skb->destructor = sock_wfree; + spin_lock_irqsave(&xs->pool->cq_lock, flags); + xskq_prod_cancel(xs->pool->cq); + spin_unlock_irqrestore(&xs->pool->cq_lock, flags); /* Free skb without triggering the perf drop trace */ consume_skb(skb); err = -EAGAIN; diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index 4a9663aa7afe..2823b7c3302d 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -334,6 +334,11 @@ static inline bool xskq_prod_is_full(struct xsk_queue *q) return xskq_prod_nb_free(q, 1) ? false : true; } +static inline void xskq_prod_cancel(struct xsk_queue *q) +{ + q->cached_prod--; +} + static inline int xskq_prod_reserve(struct xsk_queue *q) { if (xskq_prod_is_full(q))