From patchwork Wed Nov 11 21:14:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heiner Kallweit X-Patchwork-Id: 1398536 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=njnN02kX; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CWdq96c3wz9s0b for ; Thu, 12 Nov 2020 08:56:37 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726255AbgKKV4g (ORCPT ); Wed, 11 Nov 2020 16:56:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725949AbgKKV4g (ORCPT ); Wed, 11 Nov 2020 16:56:36 -0500 Received: from mail-ej1-x643.google.com (mail-ej1-x643.google.com [IPv6:2a00:1450:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E733C0613D1 for ; Wed, 11 Nov 2020 13:56:36 -0800 (PST) Received: by mail-ej1-x643.google.com with SMTP id za3so4837388ejb.5 for ; Wed, 11 Nov 2020 13:56:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:message-id:date:user-agent:mime-version :content-transfer-encoding; bh=AFKBPHIduuf4st0QmFGiVpMHUPPFJbT1J63pBPlHOtI=; b=njnN02kXpDLX0ZWJheCfpSlKo9wE0TOQGFz+gcvUrwnPDn7QZfiYS4lo2vutORe7DP CsRdRL9Dxk0+XtIec9ID1j+GH3PHrlRIBrL8iK1chbcew7aDt+SKy1ehkw+biNrh1khy WQYYEEpaDgiGtriBoTPZ3km2KemNjspc1sKtTDbRHDbUqpaPUHcyxYRDWhw3g7PlnFsV gcmVo612NoKaruGhDD7TAlYaOZRCJPSJOFv5B69i8NaNYkU4AU8PbukEJGKDOD5wmHIb FWa+OWC+X8bIMhMBFT0YnSDznzUlPSGHH0pjmiT5VLOHY+dpMaudmGFHJ4qiI+W3+Puf z0eA== 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:message-id:date:user-agent :mime-version:content-transfer-encoding; bh=AFKBPHIduuf4st0QmFGiVpMHUPPFJbT1J63pBPlHOtI=; b=Jp7REaglSGO+BciYiellBtm1D5ecZoPipfASE8VKAVJQpGVLusbe0go3DYGXN3i30y Pt2lPttHqfabOcuuaNbngGhHNwR3SA9bDyb4z1OzxjwRVgVDejKBLrxW9L+z2zG6pMOT q8EG2GpXciJblXM5LR7CfyIHpAKLG2Xu8WNmvEovfXtrggU8IsBuoL7VyvfGMn0aGjhC 7IW0UYvT38CgpomZkThPGP+O3MkNdQ3HPaREcjOf2Q1ZfyZoFlsf2+NRsSBVNACOA4YN zGLZsd5qfUffwfXFsAw8Opq4u3cN3zJy394FalpZnkjspmUaDlt6lQn3sqZXWNSkOH63 XWQg== X-Gm-Message-State: AOAM530lwUGqOYTH/HRdKXIkZ1+gzBkDSDDS6nz53QM1Or9FaF3+XmXy erxatEsMLpwiuqBk2GycZssB3HygIzljQw== X-Google-Smtp-Source: ABdhPJyEibb1aaXBu/hcFPpzZdTogEvezBvIf96HFLl70zjbCJlFrSGiQalwJZKgtqz66cTg8mr7Tg== X-Received: by 2002:a17:906:170f:: with SMTP id c15mr28020618eje.347.1605131794400; Wed, 11 Nov 2020 13:56:34 -0800 (PST) Received: from ?IPv6:2003:ea:8f23:2800:b8a2:2ad2:2cb8:3612? (p200300ea8f232800b8a22ad22cb83612.dip0.t-ipconnect.de. [2003:ea:8f23:2800:b8a2:2ad2:2cb8:3612]) by smtp.googlemail.com with ESMTPSA id y18sm1321119ejq.69.2020.11.11.13.56.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Nov 2020 13:56:33 -0800 (PST) From: Heiner Kallweit To: Jakub Kicinski , David Miller , Realtek linux nic maintainers Cc: "netdev@vger.kernel.org" Subject: [PATCH net-next] r8169: use READ_ONCE in rtl_tx_slots_avail Message-ID: <5676fee3-f6b4-84f2-eba5-c64949a371ad@gmail.com> Date: Wed, 11 Nov 2020 22:14:27 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org tp->dirty_tx and tp->cur_tx may be changed by a racing rtl_tx() or rtl8169_start_xmit(). Use READ_ONCE() to annotate the races and ensure that the compiler doesn't use cached values. Signed-off-by: Heiner Kallweit --- drivers/net/ethernet/realtek/r8169_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index aa6f8b16d..641c94a46 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -4144,7 +4144,8 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp, static bool rtl_tx_slots_avail(struct rtl8169_private *tp, unsigned int nr_frags) { - unsigned int slots_avail = tp->dirty_tx + NUM_TX_DESC - tp->cur_tx; + unsigned int slots_avail = READ_ONCE(tp->dirty_tx) + NUM_TX_DESC + - READ_ONCE(tp->cur_tx); /* A skbuff with nr_frags needs nr_frags+1 entries in the tx queue */ return slots_avail > nr_frags;