From patchwork Fri Nov 2 01:16:16 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 196430 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 893FE2C0323 for ; Fri, 2 Nov 2012 12:12:13 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760135Ab2KBBML (ORCPT ); Thu, 1 Nov 2012 21:12:11 -0400 Received: from ogre.sisk.pl ([193.178.161.156]:51571 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760019Ab2KBBMK (ORCPT ); Thu, 1 Nov 2012 21:12:10 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by ogre.sisk.pl (Postfix) with ESMTP id 437A91DFE88; Fri, 2 Nov 2012 01:57:28 +0100 (CET) Received: from ogre.sisk.pl ([127.0.0.1]) by localhost (ogre.sisk.pl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 02815-05; Fri, 2 Nov 2012 01:57:19 +0100 (CET) Received: from vostro.rjw.lan (aemi170.neoplus.adsl.tpnet.pl [79.191.60.170]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ogre.sisk.pl (Postfix) with ESMTP id 4B86F1DFDC2; Fri, 2 Nov 2012 01:57:19 +0100 (CET) From: "Rafael J. Wysocki" To: Yinghai Lu Cc: Toshi Kani , ZhangRui , Andrew Morton , Len Brown , Tang Chen , bhelgaas@google.com, jiang.liu@huawei.com, izumi.taku@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/3] Improve container_notify_cb() to support container hot-remove. Date: Fri, 02 Nov 2012 02:16:16 +0100 Message-ID: <2818025.UWNJpCeffI@vostro.rjw.lan> User-Agent: KMail/4.8.5 (Linux/3.7.0-rc3; KDE/4.8.5; x86_64; ; ) In-Reply-To: References: <1351668471-31436-1-git-send-email-tangchen@cn.fujitsu.com> <1920067.RxMJtDGai1@vostro.rjw.lan> MIME-Version: 1.0 X-Virus-Scanned: amavisd-new at ogre.sisk.pl using MkS_Vir for Linux Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thursday, November 01, 2012 04:39:50 PM Yinghai Lu wrote: > On Thu, Nov 1, 2012 at 4:15 PM, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > Subject: ACPI: Make seemingly useless check in osl.c more understandable > > > > There is a seemingly useless check in drivers/acpi/osl.c added by > > commit bc73675 (ACPI: fixes a false alarm from lockdep), which really > > is necessary to avoid false positive lockdep complaints. Document > > this and rearrange the code related to it so that it makes fewer > > checks. > > > > Signed-off-by: Rafael J. Wysocki > > --- > > drivers/acpi/osl.c | 21 ++++++++++++++------- > > 1 file changed, 14 insertions(+), 7 deletions(-) > > > > Index: linux/drivers/acpi/osl.c > > =================================================================== > > --- linux.orig/drivers/acpi/osl.c > > +++ linux/drivers/acpi/osl.c > > @@ -944,17 +944,24 @@ static acpi_status __acpi_os_execute(acp > > * because the hotplug code may call driver .remove() functions, > > * which invoke flush_scheduled_work/acpi_os_wait_events_complete > > * to flush these workqueues. > > + * > > + * To prevent lockdep from complaining unnecessarily, make sure that > > + * there is a different static lockdep key for each workqueue by using > > + * INIT_WORK() for each of them separately. > > */ > > - queue = hp ? kacpi_hotplug_wq : > > - (type == OSL_NOTIFY_HANDLER ? kacpi_notify_wq : kacpid_wq); > > - dpc->wait = hp ? 1 : 0; > > - > > - if (queue == kacpi_hotplug_wq) > > + if (hp) { > > + queue = kacpi_hotplug_wq; > > + dpc->wait = 1; > > INIT_WORK(&dpc->work, acpi_os_execute_deferred); > > - else if (queue == kacpi_notify_wq) > > + } else if (type == OSL_NOTIFY_HANDLER) { > > + queue = kacpi_notify_wq; > > + dpc->wait = 0; > > yes, much clear. > > at the same can you changne > dpc allocation from kmalloc with kzalloc instead. > > then we save two lines for dpc->wait = 0 Good idea. :-) > After that > > Acked-by: Yinghai Lu For completeness: --- From: Rafael J. Wysocki Subject: ACPI: Make seemingly useless check in osl.c more understandable There is a seemingly useless check in drivers/acpi/osl.c added by commit bc73675 (ACPI: fixes a false alarm from lockdep), which really is necessary to avoid false positive lockdep complaints. Document this and rearrange the code related to it so that it makes fewer checks. Signed-off-by: Rafael J. Wysocki Acked-by: Yinghai Lu --- drivers/acpi/osl.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) Index: linux/drivers/acpi/osl.c =================================================================== --- linux.orig/drivers/acpi/osl.c +++ linux/drivers/acpi/osl.c @@ -932,7 +932,7 @@ static acpi_status __acpi_os_execute(acp * having a static work_struct. */ - dpc = kmalloc(sizeof(struct acpi_os_dpc), GFP_ATOMIC); + dpc = kzalloc(sizeof(struct acpi_os_dpc), GFP_ATOMIC); if (!dpc) return AE_NO_MEMORY; @@ -944,17 +944,22 @@ static acpi_status __acpi_os_execute(acp * because the hotplug code may call driver .remove() functions, * which invoke flush_scheduled_work/acpi_os_wait_events_complete * to flush these workqueues. + * + * To prevent lockdep from complaining unnecessarily, make sure that + * there is a different static lockdep key for each workqueue by using + * INIT_WORK() for each of them separately. */ - queue = hp ? kacpi_hotplug_wq : - (type == OSL_NOTIFY_HANDLER ? kacpi_notify_wq : kacpid_wq); - dpc->wait = hp ? 1 : 0; - - if (queue == kacpi_hotplug_wq) + if (hp) { + queue = kacpi_hotplug_wq; + dpc->wait = 1; INIT_WORK(&dpc->work, acpi_os_execute_deferred); - else if (queue == kacpi_notify_wq) + } else if (type == OSL_NOTIFY_HANDLER) { + queue = kacpi_notify_wq; INIT_WORK(&dpc->work, acpi_os_execute_deferred); - else + } else { + queue = kacpid_wq; INIT_WORK(&dpc->work, acpi_os_execute_deferred); + } /* * On some machines, a software-initiated SMI causes corruption unless