From patchwork Mon Aug 2 13:46:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Leizhen \(ThunderTown\)" X-Patchwork-Id: 490337 Delivered-To: patch@linaro.org Received: by 2002:a05:6638:1185:0:0:0:0 with SMTP id f5csp1940416jas; Mon, 2 Aug 2021 06:47:58 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwVBjyANwZqt3IGb62pEhkiVfOEwoSXp21KNH4l/MkKiS6YKwFF8Xq3ySd1QYxlRhIDJYKC X-Received: by 2002:a6b:8f8f:: with SMTP id r137mr457323iod.185.1627912078718; Mon, 02 Aug 2021 06:47:58 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1627912078; cv=none; d=google.com; s=arc-20160816; b=ULK/u6v9lc087EPstO4VQomlj0ZSm9FQEk+4JYrxw39lIClXowS3LyPtZdU9HaHM8X 42UzRCP6qDdxmG0RHO5SYJ4O0Dg7SjxP9mhVbKOwtP3k1VBicTUAwsGWVrSqbIJUkJ+o nfgKTBoiMMovY3v0L7oMgKeECSXyavYIluf9mpAYKbUP2DGSDK/1fjStKCsCBmVNF7Jr tvjZ+5xVpBSgt+/IqCbtFVxuBGylbkVyN117FXO8ySHG+vp9TwmMQjxttkbyI+/y+R5m RGAKKYgzv6O+CweA1rocbepbys8qj/L4yy2zbnxb5Mmvd31w1YdhPSGeUHL9A9oMXjJb OzVw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=IkCtMKLMTMeCBqmlyyWVh8NrQ+1BImtl+Z+0LeDJtLY=; b=CrUlBNCw9MMLVMgR1l824sccz5PU+jAPq6U4gXvk4MLZlFKU7YHg0+4+E3soy+dhcY W/4LA/507D9uHyp2Z+BJi7xjb6lY2O5kQAYzmSopgBhldqiFibpB0b4gCm9hE47dp+p1 4YOYQ28D4OhWmzKnZrW1qmgUI7F+028xDCKCi6J3rX0hMw689eMfIP+ZbftY8PZqJRuj a8wcqkFYvm33fiI5/cAEj3jdcH9Pe3LHRKzuHMUruLpFZwv2AcQgLVA1Ub+fHyXa6cmW 6MVGaEltJs+0W46IdGXHLCDMmBijTaPysm/5G84uvysJRm/0HSMWbDQM/eicc9uQfSF+ Ydqg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=huawei.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id y11si15278928ilu.1.2021.08.02.06.47.58; Mon, 02 Aug 2021 06:47:58 -0700 (PDT) Received-SPF: pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234400AbhHBNsE (ORCPT + 12 others); Mon, 2 Aug 2021 09:48:04 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:16035 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234378AbhHBNrg (ORCPT ); Mon, 2 Aug 2021 09:47:36 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4GdfNf0m90zZwgx; Mon, 2 Aug 2021 21:43:46 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 2 Aug 2021 21:47:18 +0800 Received: from thunder-town.china.huawei.com (10.174.179.0) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Mon, 2 Aug 2021 21:47:17 +0800 From: Zhen Lei To: Greg Kroah-Hartman , stable CC: Zhen Lei , Anna-Maria Gleixner , Mike Galbraith , Sasha Levin , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , linux-kernel Subject: [PATCH 4.4 11/11] rcu: Update documentation of rcu_read_unlock() Date: Mon, 2 Aug 2021 21:46:24 +0800 Message-ID: <20210802134624.1934-12-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 In-Reply-To: <20210802134624.1934-1-thunder.leizhen@huawei.com> References: <20210802134624.1934-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.179.0] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected 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 --- include/linux/rcupdate.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) -- 2.26.0.106.g9fadedd diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 0a93e9d1708e29e..3072e9c93ae6be2 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -880,9 +880,7 @@ static __always_inline void rcu_read_lock(void) * 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