From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754753Ab3AZWhy (ORCPT ); Sat, 26 Jan 2013 17:37:54 -0500 Received: from hydra.sisk.pl ([212.160.235.94]:56736 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754639Ab3AZWhs (ORCPT ); Sat, 26 Jan 2013 17:37:48 -0500 From: "Rafael J. Wysocki" To: ACPI Devel Maling List Cc: LKML , Bjorn Helgaas , Yinghai Lu , Jiang Liu , Toshi Kani Subject: [PATCH 1/2] ACPI / scan: Make namespace scanning and trimming mutually exclusive Date: Sat, 26 Jan 2013 23:41:10 +0100 Message-ID: <3032117.IcK9I7rYQT@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.8.0-rc5; KDE/4.9.5; x86_64; ; ) In-Reply-To: <1581701.fnbebHrKch@vostro.rjw.lan> References: <1581701.fnbebHrKch@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki There is no guarantee that acpi_bus_scan() and acpi_bus_trim() will not be run in parallel for the same scope of the ACPI namespace, which may lead to a great deal of confusion, so introduce a new mutex to prevent that from happening. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) Index: linux-pm/drivers/acpi/scan.c =================================================================== --- linux-pm.orig/drivers/acpi/scan.c +++ linux-pm/drivers/acpi/scan.c @@ -52,6 +52,7 @@ static const struct acpi_device_id acpi_ static LIST_HEAD(acpi_device_list); static LIST_HEAD(acpi_bus_id_list); +static DEFINE_MUTEX(acpi_scan_lock); DEFINE_MUTEX(acpi_device_lock); LIST_HEAD(acpi_wakeup_device_list); @@ -1612,19 +1613,22 @@ static acpi_status acpi_bus_device_attac int acpi_bus_scan(acpi_handle handle) { void *device = NULL; + int error = 0; + + mutex_lock(&acpi_scan_lock); if (ACPI_SUCCESS(acpi_bus_check_add(handle, 0, NULL, &device))) acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX, acpi_bus_check_add, NULL, NULL, &device); if (!device) - return -ENODEV; - - if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL))) + error = -ENODEV; + else if (ACPI_SUCCESS(acpi_bus_device_attach(handle, 0, NULL, NULL))) acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX, acpi_bus_device_attach, NULL, NULL, NULL); - return 0; + mutex_unlock(&acpi_scan_lock); + return error; } EXPORT_SYMBOL(acpi_bus_scan); @@ -1653,6 +1657,8 @@ static acpi_status acpi_bus_remove(acpi_ void acpi_bus_trim(struct acpi_device *start) { + mutex_lock(&acpi_scan_lock); + /* * Execute acpi_bus_device_detach() as a post-order callback to detach * all ACPI drivers from the device nodes being removed. @@ -1667,6 +1673,8 @@ void acpi_bus_trim(struct acpi_device *s acpi_walk_namespace(ACPI_TYPE_ANY, start->handle, ACPI_UINT32_MAX, NULL, acpi_bus_remove, NULL, NULL); acpi_bus_remove(start->handle, 0, NULL, NULL); + + mutex_unlock(&acpi_scan_lock); } EXPORT_SYMBOL_GPL(acpi_bus_trim);