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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 3BC09C3A5A1 for ; Sun, 25 Aug 2019 18:32:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0EDAA2173E for ; Sun, 25 Aug 2019 18:32:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BIPJMU3z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728889AbfHYScU (ORCPT ); Sun, 25 Aug 2019 14:32:20 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:39915 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728863AbfHYScU (ORCPT ); Sun, 25 Aug 2019 14:32:20 -0400 Received: by mail-pl1-f194.google.com with SMTP id z3so8744931pln.6 for ; Sun, 25 Aug 2019 11:32:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=U3m17TISxgf6BUYIDX0cfztJuO/ssulmKc6XAVFQoKc=; b=BIPJMU3z8XrlwKDnv+ytHYIify/lU5Pde/kcx6iQK/RPBwUQdSijfRszyWmkQLALgu ryvKkcqUa3ReZnSwEdw+S23t5eSh+fu4XQArZqkpZhBW9IbqTKS0KTdSlq1ijWhKG3oZ qArLBbBPRLcpNAuA1KEC/Z0eQ3dkE5mx6RjGxtZsVTH7T4nlklAl6ps6e+u/xiNgWvKX 6GdMwI2FBXY/Vxf/pwDpe11b09VfWZfRNhcPYwdGv/POEnr/oimxufb3aIchwyCQHOZA v0sLm1ngO56Mg68qN8I/6xH61rvkjWy0Bmay6tp5CJlFhIA9wMf/GdVRJjoqr1Duw0Bf Wprg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=U3m17TISxgf6BUYIDX0cfztJuO/ssulmKc6XAVFQoKc=; b=Wn4lsn04S7hVX8jv6bgx1VCdvLEf4WX/BRO6qXUOsnl7Obdvjx+DrkGgVZyH76SzYe yfSjGh5vIFdNybzHL29O5pKPJ2OzOpYWHAJIWMArHcCI8EPaYE59kXgBbL3dVIWMDdtr VHi5iO68bxgfXWn/xMuZd8eXDA6qXziMD9Ckt6UeGOs9pfM6ubILWSdZYcC8i1XgYMmg DRC1FKpYSrfx0DvsfEdoLqTDR7Qg/FkdprwmkxbNHOoBiVZphQJ/w+kap3ryoYfJJ0HN gUIK5ZJKzgYwUaE45QLl9Nj4pzFfpKzF+4pc9jga4irDdtxGq4JTFRjfu3DxxhXzqq25 qayg== X-Gm-Message-State: APjAAAVF3rtZqPSufG71o5FuUD+YN4e7IoyMoRr8xAzOtl9hMv6j8dcz sqMuVcxho6jUqj9YW1Or3qzQm4iJlolZIElOpYM8syRZ X-Google-Smtp-Source: APXvYqyAnzof4Go0ZdJ0F3jPkFdK1Bl38suRuWMuRihaVQJpJeTYQeM0CXgnQx0T+EgWYX4z8atGylvvbdfGslHIcqI= X-Received: by 2002:a17:902:26b:: with SMTP id 98mr15459607plc.61.1566757939921; Sun, 25 Aug 2019 11:32:19 -0700 (PDT) MIME-Version: 1.0 References: <20190820223259.22348-1-willy@infradead.org> <20190820223259.22348-30-willy@infradead.org> In-Reply-To: From: Cong Wang Date: Sun, 25 Aug 2019 11:32:08 -0700 Message-ID: Subject: Re: [PATCH 29/38] cls_flower: Convert handle_idr to XArray To: Vlad Buslov Cc: Matthew Wilcox , "netdev@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Aug 21, 2019 at 11:27 AM Vlad Buslov wrote: > At first I was confused why you bring up rtnl lock in commit message > (flower classifier has 'unlocked' flag set and can't rely on it anymore) > but looking at the code I see that we lost rcu read lock here in commit > d39d714969cd ("idr: introduce idr_for_each_entry_continue_ul()") and you > are correctly bringing it back. Adding Cong to advise if it is okay to > wait for this patch to be accepted or we need to proceed with fixing the > missing RCU lock as a standalone patch. Hmm? Isn't ->walk() still called with RTNL lock? tcf_chain_dump() calls __tcf_get_next_proto() which asserts RTNL. So why does it still need RCU read lock when having RTNL?