From patchwork Sun Aug 8 07:22:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 493832 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=-19.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 663B2C4338F for ; Sun, 8 Aug 2021 07:23:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E17F61040 for ; Sun, 8 Aug 2021 07:23:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231247AbhHHHXU (ORCPT ); Sun, 8 Aug 2021 03:23:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:54944 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230492AbhHHHXT (ORCPT ); Sun, 8 Aug 2021 03:23:19 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 62A6160C40; Sun, 8 Aug 2021 07:22:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1628407379; bh=uhLAo5FfyVe5NiACB2W/CyEoXjolokTW49NauGIkC0w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uQ+6c+w8KrSmz/WDTHGYr/YENGI2CdfxWr+Ow+EMbqp/QfdYFuLnDze2wHox7yNAx umnnxmvFcIvpzxT3i+Ov316Hg+kng6MiIX9iWv6M776hC0VNs087TrS7MB1k4wDoY5 vnzbV7lUEDIXucG7JUfqvWe8JcXFy2yntGvrjYnM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Eric W. Biederman" , Anna-Maria Gleixner , Thomas Gleixner , "Paul E. McKenney" , bigeasy@linutronix.de, Zhen Lei , Joe Korty Subject: [PATCH 4.4 11/11] rcu: Update documentation of rcu_read_unlock() Date: Sun, 8 Aug 2021 09:22:46 +0200 Message-Id: <20210808072217.704630357@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210808072217.322468704@linuxfoundation.org> References: <20210808072217.322468704@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Anna-Maria Gleixner [ Upstream commit ec84b27f9b3b569f9235413d1945a2006b97b0aa ] Since commit b4abf91047cf ("rtmutex: Make wait_lock irq safe") the explanation in rcu_read_unlock() documentation about irq unsafe rtmutex wait_lock is no longer valid. Remove it to prevent kernel developers reading the documentation to rely on it. Suggested-by: Eric W. Biederman Signed-off-by: Anna-Maria Gleixner Signed-off-by: Thomas Gleixner Reviewed-by: Paul E. McKenney Acked-by: "Eric W. Biederman" Cc: bigeasy@linutronix.de Link: https://lkml.kernel.org/r/20180525090507.22248-2-anna-maria@linutronix.de Signed-off-by: Zhen Lei Acked-by: Joe Korty Signed-off-by: Greg Kroah-Hartman --- include/linux/rcupdate.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -880,9 +880,7 @@ static __always_inline void rcu_read_loc * Unfortunately, this function acquires the scheduler's runqueue and * priority-inheritance spinlocks. This means that deadlock could result * if the caller of rcu_read_unlock() already holds one of these locks or - * any lock that is ever acquired while holding them; or any lock which - * can be taken from interrupt context because rcu_boost()->rt_mutex_lock() - * does not disable irqs while taking ->wait_lock. + * any lock that is ever acquired while holding them. * * That said, RCU readers are never priority boosted unless they were * preempted. Therefore, one way to avoid deadlock is to make sure