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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A649CCA9ECF for ; Mon, 4 Nov 2019 17:32:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7671520869 for ; Mon, 4 Nov 2019 17:32:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ZS92UsCK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728012AbfKDRcH (ORCPT ); Mon, 4 Nov 2019 12:32:07 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:36015 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727989AbfKDRcG (ORCPT ); Mon, 4 Nov 2019 12:32:06 -0500 Received: by mail-pg1-f196.google.com with SMTP id k13so445809pgh.3; Mon, 04 Nov 2019 09:32:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=l69ummbnkucSxuM61KnWZr+QE4asTsNeQ7EDMaFQ/LQ=; b=ZS92UsCKc8Hj5ncrQDiMdwXGnAGHVrWknlQGjYTwsyXyMCvA9ohIjYNRRTmZ2GTYB2 hgHif5b5w0X8junZc4tgPrztpEKOK0v5oCg1tpuH87XrwwYdszS5IGp8fKlggsfNGw/M 09pigGUMGbFKp+Gd6cxDnZ3cohi2uPBJyxbyiqA/INFYUyGGVHBg+EDqsa35qgyNmAT3 ieqz3OzFbiIu7UhU4nw0s85ZBJtHeFl22qGI5B4wnPsf3e4PvFatnMQgOhNKQCjpCiL+ rKodU2WSddX0KyBVjT92daJBd4MNsvznTw4pzeJkyYKlBX6TcEsQ0R8j+iHLMz9OHntH d+eg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=l69ummbnkucSxuM61KnWZr+QE4asTsNeQ7EDMaFQ/LQ=; b=AlAB+ab7FXWeyh0TpZlMUcFFLPpka23Na1dtxausajG0VCpHf5LH9cpZXuD/5xkxE8 JsqZdajsOTzhiz1L2+x+xuWOahOsBjPWny7lyr46wuoJseWZW1jRAPqrx5GNz3IWozZy GgzBH5zTaom+bEipaqxjUBY9b3H6abdKq+Lxct5jLL1YJPxd7TMYXHyAI93rTc7yAXtL ZAOepBEvA9atGAu0YJ+uHo1qfjuuHd81fP5w3vZf75q4nHdcEw7bTe7533BMbKngj/aq nFs/mmeLWifi9aGGYXLSXcXL9aVjForiDmjhjrYYixKHxWWhqMFpC2s/emGpFuh0jhA2 K5lQ== X-Gm-Message-State: APjAAAWwDrw1SME/oXRd47OIUeEkgTmxPJC2j2HdCj9Dmo3Q+xtyRBxm fCOS47aJuA1Hhvn597YQcdI= X-Google-Smtp-Source: APXvYqySUtitKYMsIcxyNKY9L3vTqqA7owzP7uIwB7NS8uGIXoUwQ9RZ2TI3r0LcmXstWG5gJtCkzw== X-Received: by 2002:a63:134a:: with SMTP id 10mr30908497pgt.441.1572888725334; Mon, 04 Nov 2019 09:32:05 -0800 (PST) Received: from workstation-kernel-dev ([139.5.253.170]) by smtp.gmail.com with ESMTPSA id 81sm20455000pfx.142.2019.11.04.09.32.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Nov 2019 09:32:04 -0800 (PST) Date: Mon, 4 Nov 2019 23:01:56 +0530 From: Amol Grover To: Jani Nikula Cc: "Paul E. McKenney" , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , Jonathan Corbet , rcu@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, Shuah Khan Subject: Re: [PATCH] Documentation: RCU: whatisRCU: Fix formatting for section 2 Message-ID: <20191104173156.GA15267@workstation-kernel-dev> References: <20191104133315.GA14499@workstation-kernel-dev> <87pni77jvt.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87pni77jvt.fsf@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Mon, Nov 04, 2019 at 05:15:34PM +0200, Jani Nikula wrote: > On Mon, 04 Nov 2019, Amol Grover wrote: > > Convert RCU API method text to sub-headings and > > add hyperlink and superscript to 2 literary notes > > under rcu_dereference() section > > > > Signed-off-by: Amol Grover > > --- > > Documentation/RCU/whatisRCU.rst | 34 +++++++++++++++++++++++++++------ > > 1 file changed, 28 insertions(+), 6 deletions(-) > > > > diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst > > index ae40c8bcc56c..3cf6e17d0065 100644 > > --- a/Documentation/RCU/whatisRCU.rst > > +++ b/Documentation/RCU/whatisRCU.rst > > @@ -150,6 +150,7 @@ later. See the kernel docbook documentation for more info, or look directly > > at the function header comments. > > > > rcu_read_lock() > > +^^^^^^^^^^^^^^^ > > > > void rcu_read_lock(void); > > > > @@ -164,6 +165,7 @@ rcu_read_lock() > > longer-term references to data structures. > > > > rcu_read_unlock() > > +^^^^^^^^^^^^^^^^^ > > > > void rcu_read_unlock(void); > > > > @@ -172,6 +174,7 @@ rcu_read_unlock() > > read-side critical sections may be nested and/or overlapping. > > > > synchronize_rcu() > > +^^^^^^^^^^^^^^^^^ > > > > void synchronize_rcu(void); > > > > @@ -225,6 +228,7 @@ synchronize_rcu() > > checklist.txt for some approaches to limiting the update rate. > > > > rcu_assign_pointer() > > +^^^^^^^^^^^^^^^^^^^^ > > > > void rcu_assign_pointer(p, typeof(p) v); > > > > @@ -245,6 +249,7 @@ rcu_assign_pointer() > > the _rcu list-manipulation primitives such as list_add_rcu(). > > > > rcu_dereference() > > +^^^^^^^^^^^^^^^^^ > > > > typeof(p) rcu_dereference(p); > > > > @@ -279,8 +284,10 @@ rcu_dereference() > > if an update happened while in the critical section, and incur > > unnecessary overhead on Alpha CPUs. > > > > +.. _back_to_1: > > + > > Note that the value returned by rcu_dereference() is valid > > - only within the enclosing RCU read-side critical section [1]. > > + only within the enclosing RCU read-side critical section |cs_1|. > > For example, the following is -not- legal:: > > > > rcu_read_lock(); > > @@ -298,15 +305,27 @@ rcu_dereference() > > it was acquired is just as illegal as doing so with normal > > locking. > > > > +.. _back_to_2: > > + > > As with rcu_assign_pointer(), an important function of > > rcu_dereference() is to document which pointers are protected by > > RCU, in particular, flagging a pointer that is subject to changing > > at any time, including immediately after the rcu_dereference(). > > And, again like rcu_assign_pointer(), rcu_dereference() is > > typically used indirectly, via the _rcu list-manipulation > > - primitives, such as list_for_each_entry_rcu() [2]. > > + primitives, such as list_for_each_entry_rcu() |entry_2|. > > + > > +.. |cs_1| raw:: html > > Please don't use raw. It's ugly and error prone. We have some raw output > for latex, but this would be the first for html. > > What are you trying to achieve? Hi Jani, While going through the documentation I encountered a few footnotes (numbers [1] and [2]) which referenced the actual footnote somewhere below the text. They were particularly not straight-forward to find hence I decided to link them to the footnote text which could be done using inline markup. Then I tried to make them more appealing by converting to super-scripts (the way they look like in books and websites). However, nested inline markup is not yet possible in reST hence I went with the html way to achieve the same. Too much? Thank you Amol > > BR, > Jani. > > > + > > + [1] > > + > > +.. |entry_2| raw:: html > > > > - [1] The variant rcu_dereference_protected() can be used outside > > + [2] > > + > > +.. _cs: > > + > > + \ :sup:`[1]`\ The variant rcu_dereference_protected() can be used outside > > of an RCU read-side critical section as long as the usage is > > protected by locks acquired by the update-side code. This variant > > avoids the lockdep warning that would happen when using (for > > @@ -317,15 +336,18 @@ rcu_dereference() > > a lockdep expression to indicate which locks must be acquired > > by the caller. If the indicated protection is not provided, > > a lockdep splat is emitted. See Documentation/RCU/Design/Requirements/Requirements.rst > > - and the API's code comments for more details and example usage. > > + and the API's code comments for more details and example usage. :ref:`back ` > > + > > + > > +.. _entry: > > > > - [2] If the list_for_each_entry_rcu() instance might be used by > > + \ :sup:`[2]`\ If the list_for_each_entry_rcu() instance might be used by > > update-side code as well as by RCU readers, then an additional > > lockdep expression can be added to its list of arguments. > > For example, given an additional "lock_is_held(&mylock)" argument, > > the RCU lockdep code would complain only if this instance was > > invoked outside of an RCU read-side critical section and without > > - the protection of mylock. > > + the protection of mylock. :ref:`back ` > > > > The following diagram shows how each API communicates among the > > reader, updater, and reclaimer. > > -- > Jani Nikula, Intel Open Source Graphics Center