From patchwork Thu Sep 24 00:29:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geliang Tang X-Patchwork-Id: 1370172 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=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=qazrzgmE; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4Bxbxd1Wghz9sSt for ; Thu, 24 Sep 2020 10:48:05 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726714AbgIXAsB (ORCPT ); Wed, 23 Sep 2020 20:48:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726466AbgIXAsB (ORCPT ); Wed, 23 Sep 2020 20:48:01 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D674CC0613CE; Wed, 23 Sep 2020 17:48:00 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id d13so798803pgl.6; Wed, 23 Sep 2020 17:48:00 -0700 (PDT) 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 :in-reply-to:references; bh=IeSXMBVcVqOJv+ick5hpJlRuUlPUh1dEBXZ1ahX+5iQ=; b=qazrzgmEz80xNxddpR8Ymwev6mBT9p1Gd//S9xmd/LufiF1CERFfGj5PtdccwRv78S 1sP3FOfQWXHM4Wt9V+qFTib5icZjrlDuKUeqFXGgfwDjpqy53DIHwm3taMwi1tUXN3aR EXCPBtVQgDBVhn7p+jnj2C5Tn//tntVHn5YSmNMPl8CgmocUlufQk0+L4EU8oeAi08xf WN1q9ZEz570rnwvv8+nyeLjlJNdf24x2n68udhYpRECVn/6+syTGiyz7euVG2Y/jQT4W CbwC0MPjz4KqHRwKcGKgRP2l0Pv3cvj6+iw6TZc2hx7XksY9YHZpWmtLme4957hBRfG0 WXYA== 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:in-reply-to:references; bh=IeSXMBVcVqOJv+ick5hpJlRuUlPUh1dEBXZ1ahX+5iQ=; b=s8B3/ZApwoj5312790VdcAyI9uxXQznyGA7jpbzkwQqQRK+upDpv8dcTIx5zypYdHd F95Su+UlgfLuxQujfrMmjZkwo++AiwVSRvoBArc9/m4zDUjqkVWvia1hH+g6HZy7vZTr Njtf4aV0XIZq5IZnYEHDJQsKqMAR/2NsRMLg5gBmISSEjo71cQB5/bDkxZPLiNI8fmjS TrSKntjJgMKsAaRTmPaWJtL0e1ssi5F3XNECMv8Ov01GcXd7bKCjBjtsCu5vRzjkiidN 3+sMcXcxgYW4RIKTSoOazkEqNlRUyq4Ab7dOn2zVr5oBTUw9yHfehSiRLuUp8v2ZNM7l EJQA== X-Gm-Message-State: AOAM533B/MP8pajzu/1gd4OtjR5kniMavHLAqPA4pbmnLolEsgK6Kr74 yveVb2g2cBWbgSE3Cj4Qdz0= X-Google-Smtp-Source: ABdhPJwTXwvZmpuuH0Dohsw8+m3zb/qXZWYKtOXMNtxNyDebN16JVnpjXeNu6RXcgz8x+zxpLvk3cA== X-Received: by 2002:a62:3706:0:b029:142:2501:39e5 with SMTP id e6-20020a6237060000b0290142250139e5mr2346642pfa.52.1600908480415; Wed, 23 Sep 2020 17:48:00 -0700 (PDT) Received: from localhost ([43.224.245.180]) by smtp.gmail.com with ESMTPSA id v1sm5724363pjn.1.2020.09.23.17.47.59 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Sep 2020 17:47:59 -0700 (PDT) From: Geliang Tang To: Mat Martineau , Matthieu Baerts , "David S. Miller" , Jakub Kicinski Cc: Geliang Tang , netdev@vger.kernel.org, mptcp@lists.01.org, linux-kernel@vger.kernel.org Subject: [MPTCP][PATCH net-next 07/16] mptcp: add accept_subflow re-check Date: Thu, 24 Sep 2020 08:29:53 +0800 Message-Id: <98bcc56283c482c294bd6ae9ce1476821ddc6837.1600853093.git.geliangtang@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: <7b0898eff793dde434464b5fac2629739d9546fd.1600853093.git.geliangtang@gmail.com> References: <430dd4f9c241ae990a5cfa6809276b36993ce91b.1600853093.git.geliangtang@gmail.com> <7b0898eff793dde434464b5fac2629739d9546fd.1600853093.git.geliangtang@gmail.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The re-check of pm->accept_subflow with pm->lock held was missing, this patch fixed it. Suggested-by: Mat Martineau Reviewed-by: Mat Martineau Signed-off-by: Geliang Tang --- net/mptcp/pm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 39a76620d0a5..be4157279e15 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -48,7 +48,7 @@ void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side) bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk) { struct mptcp_pm_data *pm = &msk->pm; - int ret; + int ret = 0; pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows, pm->subflows_max, READ_ONCE(pm->accept_subflow)); @@ -58,9 +58,11 @@ bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk) return false; spin_lock_bh(&pm->lock); - ret = pm->subflows < pm->subflows_max; - if (ret && ++pm->subflows == pm->subflows_max) - WRITE_ONCE(pm->accept_subflow, false); + if (READ_ONCE(pm->accept_subflow)) { + ret = pm->subflows < pm->subflows_max; + if (ret && ++pm->subflows == pm->subflows_max) + WRITE_ONCE(pm->accept_subflow, false); + } spin_unlock_bh(&pm->lock); return ret;