Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932722Ab3CGSmu (ORCPT ); Thu, 7 Mar 2013 13:42:50 -0500 Received: from mail-oa0-f52.google.com ([209.85.219.52]:33843 "EHLO mail-oa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756288Ab3CGSmr (ORCPT ); Thu, 7 Mar 2013 13:42:47 -0500 MIME-Version: 1.0 In-Reply-To: <20130307175359.GB15631@redhat.com> References: <201303042055.38040.maciej.rutecki@gmail.com> <1362504883-9180-1-git-send-email-msb@chromium.org> <20130305174838.GA7276@redhat.com> <20130305180542.GA12738@redhat.com> <20130305232603.GA16045@khazad-dum.debian.net> <20130306154420.GA7697@redhat.com> <20130306233232.GA12645@khazad-dum.debian.net> <20130307175305.GA15631@redhat.com> <20130307175359.GB15631@redhat.com> Date: Thu, 7 Mar 2013 10:42:46 -0800 X-Google-Sender-Auth: nST2HrRSL2ELCMN_RLhOaCy6yQM Message-ID: Subject: Re: [PATCH 1/1] thinkpad-acpi: kill hotkey_thread_mutex From: Mandeep Singh Baines To: Oleg Nesterov Cc: Henrique de Moraes Holschuh , Linux Kernel Mailing List , linux-acpi@vger.kernel.org, ibm-acpi@hmh.eng.br, ibm-acpi-devel@lists.sourceforge.net, platform-driver-x86@vger.kernel.org, Aaron Lu , Tejun Heo , Andrew Morton , Artem Savkov Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2307 Lines: 67 On Thu, Mar 7, 2013 at 9:53 AM, Oleg Nesterov wrote: > hotkey_kthread() does try_to_freeze() under hotkey_thread_mutex. > > We can simply kill this mutex, hotkey_poll_stop_sync() does not need > to serialize with hotkey_kthread(). When kthread_stop() returns the > thread is already dead, it called do_exit()->complete_vfork_done(). > > Reported-by: Artem Savkov > Reported-by: Maciej Rutecki > Signed-off-by: Oleg Nesterov > Reviewed-by: Mandeep Singh Baines > --- x/drivers/platform/x86/thinkpad_acpi.c > +++ x/drivers/platform/x86/thinkpad_acpi.c > @@ -1965,9 +1965,6 @@ struct tp_nvram_state { > /* kthread for the hotkey poller */ > static struct task_struct *tpacpi_hotkey_task; > > -/* Acquired while the poller kthread is running, use to sync start/stop */ > -static struct mutex hotkey_thread_mutex; > - > /* > * Acquire mutex to write poller control variables as an > * atomic block. > @@ -2463,8 +2460,6 @@ static int hotkey_kthread(void *data) > unsigned int poll_freq; > bool was_frozen; > > - mutex_lock(&hotkey_thread_mutex); > - > if (tpacpi_lifecycle == TPACPI_LIFE_EXITING) > goto exit; > > @@ -2524,7 +2519,6 @@ static int hotkey_kthread(void *data) > } > > exit: > - mutex_unlock(&hotkey_thread_mutex); > return 0; > } > > @@ -2534,9 +2528,6 @@ static void hotkey_poll_stop_sync(void) > if (tpacpi_hotkey_task) { > kthread_stop(tpacpi_hotkey_task); > tpacpi_hotkey_task = NULL; > - mutex_lock(&hotkey_thread_mutex); > - /* at this point, the thread did exit */ > - mutex_unlock(&hotkey_thread_mutex); > } > } > > @@ -3235,7 +3226,6 @@ static int __init hotkey_init(struct ibm > mutex_init(&hotkey_mutex); > > #ifdef CONFIG_THINKPAD_ACPI_HOTKEY_POLL > - mutex_init(&hotkey_thread_mutex); > mutex_init(&hotkey_thread_data_mutex); > #endif > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/