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SubjectRe: [PATCH] ACPI: fix acpi_power_off lockdep splat
Date
On Saturday, July 02, 2011, Andrea Righi wrote:
> Implement acpi_os_create_lock() as a C-preprocessor macro to assign
> unique lock_class_key to dynamically allocated locks and suppress wrong
> lockdep warnings.
>
> This fixes:
> https://bugzilla.kernel.org/show_bug.cgi?id=38152
>
> Reported-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Andrea Righi <andrea@betterlinux.com>

So, how exactly does it work?

> ---
> drivers/acpi/osl.c | 2 +-
> include/acpi/acpiosxf.h | 12 +++++++++++-
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 52ca964..2a67602 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -1336,7 +1336,7 @@ EXPORT_SYMBOL(acpi_resources_are_enforced);
> * Create and initialize a spinlock.
> */
> acpi_status
> -acpi_os_create_lock(acpi_spinlock *out_handle)
> +__acpi_os_create_lock(acpi_spinlock *out_handle)
> {
> spinlock_t *lock;
>
> diff --git a/include/acpi/acpiosxf.h b/include/acpi/acpiosxf.h
> index a756bc8..4a0385d 100644
> --- a/include/acpi/acpiosxf.h
> +++ b/include/acpi/acpiosxf.h
> @@ -99,7 +99,17 @@ acpi_os_table_override(struct acpi_table_header *existing_table,
> * Spinlock primitives
> */
> acpi_status
> -acpi_os_create_lock(acpi_spinlock *out_handle);
> +__acpi_os_create_lock(acpi_spinlock *out_handle);
> +
> +#define acpi_os_create_lock(__handle) \
> +({ \
> + acpi_status ret; \
> + \
> + ret = __acpi_os_create_lock(__handle); \
> + if (ret == AE_OK) \
> + spin_lock_init(*(__handle)); \

It seems that spin_lock_init() has already been done on *__handle, right?

> + ret; \
> +})
>
> void acpi_os_delete_lock(acpi_spinlock handle);

Rafael


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