From 07e49a7a31153a95caa270d8ad7350a0bcd4d511 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 6 Jul 2011 20:44:25 +0200 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 Signed-off-by: Len Brown --- include/acpi/platform/aclinux.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/acpi/platform') diff --git a/include/acpi/platform/aclinux.h b/include/acpi/platform/aclinux.h index 5d2a5e9544d9..2ce1be9f6291 100644 --- a/include/acpi/platform/aclinux.h +++ b/include/acpi/platform/aclinux.h @@ -159,6 +159,24 @@ static inline void *acpi_os_acquire_object(acpi_cache_t * cache) } 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__ */ -- cgit v1.2.2