Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932625Ab3CGR4A (ORCPT ); Thu, 7 Mar 2013 12:56:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:31723 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756060Ab3CGRz7 (ORCPT ); Thu, 7 Mar 2013 12:55:59 -0500 Date: Thu, 7 Mar 2013 18:53:59 +0100 From: Oleg Nesterov To: Henrique de Moraes Holschuh Cc: Mandeep Singh Baines , 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 Subject: [PATCH 1/1] thinkpad-acpi: kill hotkey_thread_mutex Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130307175305.GA15631@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1935 Lines: 63 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 --- 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/