From patchwork Mon Mar 10 20:34:58 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 3805751 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 34A7BBF540 for ; Mon, 10 Mar 2014 20:35:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 59ECC202A1 for ; Mon, 10 Mar 2014 20:35:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A543202F0 for ; Mon, 10 Mar 2014 20:35:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754229AbaCJUfU (ORCPT ); Mon, 10 Mar 2014 16:35:20 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:52861 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753901AbaCJUfQ (ORCPT ); Mon, 10 Mar 2014 16:35:16 -0400 Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 11 Mar 2014 06:35:14 +1000 Received: from d23dlp02.au.ibm.com (202.81.31.213) by e23smtp06.au.ibm.com (202.81.31.212) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 11 Mar 2014 06:35:11 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 959AD2BB003F; Tue, 11 Mar 2014 07:35:10 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s2AKYu9m5702006; Tue, 11 Mar 2014 07:34:56 +1100 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s2AKZ8R6027146; Tue, 11 Mar 2014 07:35:10 +1100 Received: from srivatsabhat.in.ibm.com ([9.79.217.186]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s2AKZ2tU027067; Tue, 11 Mar 2014 07:35:03 +1100 From: "Srivatsa S. Bhat" Subject: [PATCH v3 07/52] ia64, topology: Fix CPU hotplug callback registration To: paulus@samba.org, oleg@redhat.com, mingo@kernel.org, rjw@rjwysocki.net, rusty@rustcorp.com.au, peterz@infradead.org, tglx@linutronix.de, akpm@linux-foundation.org Cc: paulmck@linux.vnet.ibm.com, tj@kernel.org, walken@google.com, ego@linux.vnet.ibm.com, linux@arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-pm@vger.kernel.org, linuxppc-dev@ozlabs.org, srivatsa.bhat@linux.vnet.ibm.com, Tony Luck , Fenghua Yu , Ingo Molnar , linux-ia64@vger.kernel.org, "Srivatsa S. Bhat" Date: Tue, 11 Mar 2014 02:04:58 +0530 Message-ID: <20140310203458.10746.59610.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20140310203312.10746.310.stgit@srivatsabhat.in.ibm.com> References: <20140310203312.10746.310.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14031020-7014-0000-0000-0000047B6D31 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the topology code in ia64 by using this latter form of callback registration. Cc: Tony Luck Cc: Fenghua Yu Cc: Ingo Molnar Cc: linux-ia64@vger.kernel.org Signed-off-by: Srivatsa S. Bhat --- arch/ia64/kernel/topology.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/ia64/kernel/topology.c b/arch/ia64/kernel/topology.c index ca69a5a..f295f9a 100644 --- a/arch/ia64/kernel/topology.c +++ b/arch/ia64/kernel/topology.c @@ -454,12 +454,16 @@ static int __init cache_sysfs_init(void) { int i; + cpu_notifier_register_begin(); + for_each_online_cpu(i) { struct device *sys_dev = get_cpu_device((unsigned int)i); cache_add_dev(sys_dev); } - register_hotcpu_notifier(&cache_cpu_notifier); + __register_hotcpu_notifier(&cache_cpu_notifier); + + cpu_notifier_register_done(); return 0; }