From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755388Ab1GFSn5 (ORCPT ); Wed, 6 Jul 2011 14:43:57 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:33329 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754850Ab1GFSn4 (ORCPT ); Wed, 6 Jul 2011 14:43:56 -0400 From: "Rafael J. Wysocki" To: Len Brown Subject: [Resend/Update][PATCH] ACPI: Fix lockdep false positives in acpi_power_off() Date: Wed, 6 Jul 2011 20:44:25 +0200 User-Agent: KMail/1.13.6 (Linux/3.0.0-rc5+; KDE/4.6.0; x86_64; ; ) Cc: Florian Mickler , Andrea Righi , Peter Zijlstra , Ingo Molnar , Borislav Petkov , Maciej Rutecki , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org References: <1309684450-24549-1-git-send-email-andrea@betterlinux.com> <201107050132.11996.rjw@sisk.pl> <20110705100358.6857b235@schatten.dmk.lab> In-Reply-To: <20110705100358.6857b235@schatten.dmk.lab> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201107062044.25387.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki Subject: ACPI: Fix lockdep false positives in acpi_power_off() All ACPICA locks are allocated by the same function, acpi_os_create_lock(), with the help of a local variable called "lock". Thus, when lockdep is enabled, it uses "lock" as the name of all those locks and regards them as instances of the same lock, which causes it to report possible locking problems with them when there aren't any. To work around this problem, define acpi_os_create_lock() as a macro and make it pass its argument to spin_lock_init(), so that lockdep uses it as the name of the new lock. Define this macron in a Linux-specific file, to minimize the resulting modifications of the OS-independent ACPICA parts. This change is based on an earlier patch from Andrea Righi and it addresses a regression from 2.6.39 tracked as https://bugzilla.kernel.org/show_bug.cgi?id=38152 Signed-off-by: Rafael J. Wysocki Reported-and-tested-by: Borislav Petkov Tested-by: Andrea Righi Reviewed-by: Florian Mickler --- drivers/acpi/osl.c | 17 ----------------- include/acpi/acpiosxf.h | 3 +++ include/acpi/platform/aclinux.h | 18 ++++++++++++++++++ 3 files changed, 21 insertions(+), 17 deletions(-) Index: linux-2.6/drivers/acpi/osl.c =================================================================== --- linux-2.6.orig/drivers/acpi/osl.c +++ linux-2.6/drivers/acpi/osl.c @@ -1333,23 +1333,6 @@ int acpi_resources_are_enforced(void) EXPORT_SYMBOL(acpi_resources_are_enforced); /* - * Create and initialize a spinlock. - */ -acpi_status -acpi_os_create_lock(acpi_spinlock *out_handle) -{ - spinlock_t *lock; - - lock = ACPI_ALLOCATE(sizeof(spinlock_t)); - if (!lock) - return AE_NO_MEMORY; - spin_lock_init(lock); - *out_handle = lock; - - return AE_OK; -} - -/* * Deallocate the memory for a spinlock. */ void acpi_os_delete_lock(acpi_spinlock handle) Index: linux-2.6/include/acpi/acpiosxf.h =================================================================== --- linux-2.6.orig/include/acpi/acpiosxf.h +++ linux-2.6/include/acpi/acpiosxf.h @@ -98,8 +98,11 @@ acpi_os_table_override(struct acpi_table /* * Spinlock primitives */ + +#ifndef acpi_os_create_lock acpi_status acpi_os_create_lock(acpi_spinlock *out_handle); +#endif void acpi_os_delete_lock(acpi_spinlock handle); Index: linux-2.6/include/acpi/platform/aclinux.h =================================================================== --- linux-2.6.orig/include/acpi/platform/aclinux.h +++ linux-2.6/include/acpi/platform/aclinux.h @@ -159,6 +159,24 @@ static inline void *acpi_os_acquire_obje } while (0) #endif +/* + * When lockdep is enabled, the spin_lock_init() macro stringifies it's + * argument and uses that as a name for the lock in debugging. + * By executing spin_lock_init() in a macro the key changes from "lock" for + * all locks to the name of the argument of acpi_os_create_lock(), which + * prevents lockdep from reporting false positives for ACPICA locks. + */ +#define acpi_os_create_lock(__handle) \ +({ \ + spinlock_t *lock = ACPI_ALLOCATE(sizeof(*lock)); \ + \ + if (lock) { \ + *(__handle) = lock; \ + spin_lock_init(*(__handle)); \ + } \ + lock ? AE_OK : AE_NO_MEMORY; \ +}) + #endif /* __KERNEL__ */ #endif /* __ACLINUX_H__ */