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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 76130C33CB1 for ; Fri, 17 Jan 2020 10:09:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 553982087E for ; Fri, 17 Jan 2020 10:09:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729285AbgAQKJS (ORCPT ); Fri, 17 Jan 2020 05:09:18 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:55439 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729213AbgAQKJQ (ORCPT ); Fri, 17 Jan 2020 05:09:16 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1isOYv-0005az-Uy; Fri, 17 Jan 2020 11:09:10 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id A6F851C19CC; Fri, 17 Jan 2020 11:09:09 +0100 (CET) Date: Fri, 17 Jan 2020 10:09:09 -0000 From: "tip-bot2 for Waiman Long" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/core] locking/qspinlock: Fix inaccessible URL of MCS lock paper Cc: Waiman Long , "Peter Zijlstra (Intel)" , Will Deacon , x86 , LKML In-Reply-To: <20200107174914.4187-1-longman@redhat.com> References: <20200107174914.4187-1-longman@redhat.com> MIME-Version: 1.0 Message-ID: <157925574948.396.17056541510267349194.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/core branch of tip: Commit-ID: 57097124cbbd310cc2b5884189e22e60a3c20514 Gitweb: https://git.kernel.org/tip/57097124cbbd310cc2b5884189e22e60a3c20514 Author: Waiman Long AuthorDate: Tue, 07 Jan 2020 12:49:14 -05:00 Committer: Peter Zijlstra CommitterDate: Fri, 17 Jan 2020 10:19:30 +01:00 locking/qspinlock: Fix inaccessible URL of MCS lock paper It turns out that the URL of the MCS lock paper listed in the source code is no longer accessible. I did got question about where the paper was. This patch updates the URL to BZ 206115 which contains a copy of the paper from https://www.cs.rochester.edu/u/scott/papers/1991_TOCS_synch.pdf Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Link: https://lkml.kernel.org/r/20200107174914.4187-1-longman@redhat.com --- kernel/locking/qspinlock.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 2473f10..b9515fc 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -31,14 +31,15 @@ /* * The basic principle of a queue-based spinlock can best be understood * by studying a classic queue-based spinlock implementation called the - * MCS lock. The paper below provides a good description for this kind - * of lock. + * MCS lock. A copy of the original MCS lock paper ("Algorithms for Scalable + * Synchronization on Shared-Memory Multiprocessors by Mellor-Crummey and + * Scott") is available at * - * http://www.cise.ufl.edu/tr/DOC/REP-1992-71.pdf + * https://bugzilla.kernel.org/show_bug.cgi?id=206115 * - * This queued spinlock implementation is based on the MCS lock, however to make - * it fit the 4 bytes we assume spinlock_t to be, and preserve its existing - * API, we must modify it somehow. + * This queued spinlock implementation is based on the MCS lock, however to + * make it fit the 4 bytes we assume spinlock_t to be, and preserve its + * existing API, we must modify it somehow. * * In particular; where the traditional MCS lock consists of a tail pointer * (8 bytes) and needs the next pointer (another 8 bytes) of its own node to