lkml.org 
[lkml]   [2011]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ACPI: fix acpi_power_off lockdep splat
On Sun, 3 Jul 2011 08:58:41 +0200
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> 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?

The spin_lock_init macro stringifies it's argument and uses that as a
name for the lock in the debugging.

By re-executing spin_lock_init (have not checked if that harms
anything, but it should be ok) in the _macro_ the key changes from
"lock" for all three locks to the actual argument
"&acpi_gbl_global_lock_pending_lock", "&acpi_gbl_gpe_lock" or
"&acpi_gbl_hardware_lock".

Regards,
Flo

> > ---
> > 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


\
 
 \ /
  Last update: 2011-07-03 10:23    [W:0.051 / U:6.348 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site