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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 EE3C1C433C1 for ; Tue, 30 Mar 2021 16:14:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C840619C5 for ; Tue, 30 Mar 2021 16:14:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232001AbhC3QNr (ORCPT ); Tue, 30 Mar 2021 12:13:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231627AbhC3QNa (ORCPT ); Tue, 30 Mar 2021 12:13:30 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF990C061574 for ; Tue, 30 Mar 2021 09:13:29 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id i6so4899918pgs.1 for ; Tue, 30 Mar 2021 09:13:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=DHZ3uymJvGJN87q3+1H8w5ANstp2AzuWt3zz7s9SIW8=; b=XI4RWwxu6zG/DEeBZgDsKsoFzdG045MzJdjbDe6R9W9TCTSMETJ75f0UmZi1maj1IK /568KJzqvBzqw386YgzSRFHShMG3tdYm/ynI/hNbmH1kq+mnm3AUZNsC6Eup3qBUDcOj OAzfRnJgkQ7zjlYlemWrHY2sAGfw8DitP8BqilmKkfbgmA4UqKVCaNXYFsSXgoQQarl8 zjH/z9rq7OkPXnzmff+SszAYmzb7l/Y0OQi0QsbtwhX4jNQ6QPdBeO/1U433EjKu/SYY uOkkY7WJHJdgCNdHoqnbcXzVCgKHVt0QmhvNBNTMmSX+3mTQPbHXsDQFzYU5lChb8pzd OOsg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=DHZ3uymJvGJN87q3+1H8w5ANstp2AzuWt3zz7s9SIW8=; b=HT9Rx9VPrPVUBfYHQAOMUoQI14HDzmmCxB7K5L1fjjyi3Cqzc2zVtoybKJvJULqe1a D0hHEZoH3auincGb8mcR8ieUAS/GlzNcC4+h/yN+hffCR+WEzltNF0WTbpB4wd0vqLO5 gLWeh1qgIY55LtyrZ6gqvzpaw0VR4YQ/ItQFXdHD0sfQgA1Q/wnVL4UR/jHgn9v+IgZd 4FtAkZIzb22Bf/6tAie0ydVir1tI/LTDUY8MmCvtbci+gZ8O4r+JR2E0KF5X7tOzGfGb sDHswAhgugMsx8Ab0QN3zvOkVbNRzeS0EzlOurlJJ6Toc6mm4qf4tCABoj/fm+i260YA 26kg== X-Gm-Message-State: AOAM532bY/uo5jI3KI+cRxGdB9QzGVcMRsRC7Ez2AhOYvTKvAeKi9AyJ 1VP4D6AMn9sHfseXswz6jFM= X-Google-Smtp-Source: ABdhPJxiEi7Xnb/x9/DTjAYkapOdcEsJjY2I0YkPLYSFBMg4LG43U75k5lrdWbXc6tDhFJLlRKa9Ow== X-Received: by 2002:aa7:8814:0:b029:21d:d2ce:7be with SMTP id c20-20020aa788140000b029021dd2ce07bemr29680610pfo.80.1617120809489; Tue, 30 Mar 2021 09:13:29 -0700 (PDT) Received: from [192.168.0.4] ([49.173.165.50]) by smtp.gmail.com with ESMTPSA id 81sm21110770pfu.164.2021.03.30.09.13.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 30 Mar 2021 09:13:29 -0700 (PDT) Subject: Re: [PATCH net-next] mld: add missing rtnl_lock() in do_ipv6_getsockopt() To: Eric Dumazet Cc: netdev , David Miller , Hideaki YOSHIFUJI , David Ahern , Jakub Kicinski References: <20210330153106.31614-1-ap420073@gmail.com> <634ed5a7-eccc-3749-e386-841141a30038@gmail.com> From: Taehee Yoo Message-ID: Date: Wed, 31 Mar 2021 01:13:25 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 3/31/21 1:08 AM, Eric Dumazet wrote: > On Tue, Mar 30, 2021 at 6:02 PM Taehee Yoo wrote: >> >> On 3/31/21 12:40 AM, Eric Dumazet wrote: >> > This seems a serious regression compared to old code (in net tree) >> > >> > Have you added RTNL requirement in all this code ? >> > >> > We would like to use RTNL only if strictly needed. >> >> Yes, I agree with you. >> This patchset actually relies on existed RTNL, which is >> setsockopt_needs_rtnl(). >> And remained RTNL was replaced by mc_lock. >> So, this patchset actually doesn't add new RTNL except in this case. >> >> Fortunately, I think It can be replaced by RCU because, >> 1. ip6_mc_msfget() doesn't need the sleepable functions. >> 2. It is not the write critical section. >> So, RCU can be used instead of RTNL for ip6_mc_msfget(). >> How do you think about it? > > Yes please, do not add RTNL here if we can avoid it. > Okay, I will send a new patch. > Otherwise some applications will slow down the whole stack, even with > different containers/netns. > > (There is a single RTNL for the whole machine) > Thanks a lot for the review!