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PM / Runtime: Add might_sleep() to runtime PM functions 

Some of the entry points to pm runtime are not safe to
call in atomic context unless pm_runtime_irq_safe() has
been called.  Inspecting the code, it is not immediately
obvious that the functions sleep at all, as they run
inside a spin_lock_irqsave, but under some conditions
they can drop the lock and turn on irqs.

If a driver incorrectly calls the pm_runtime apis, it can
cause sleeping and irq processing when it expects to stay
in atomic context.

Add might_sleep_if to the majority of the __pm_runtime_* entry points
to enforce correct usage.

Add pm_runtime_put_sync_autosuspend to the list of
functions that can be called in atomic context.

Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Colin Cross 2011-08-08 23:39:36 +02:00 committed by Rafael J. Wysocki
parent 17f2ae7f67
commit 311aab73d2
2 changed files with 13 additions and 3 deletions
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1
Documentation/power/runtime_pm.txt
View File

@ -484,6 +484,7 @@ pm_runtime_resume()
pm_runtime_get_sync()
pm_runtime_put_sync()
pm_runtime_put_sync_suspend()
pm_runtime_put_sync_autosuspend()
5. Runtime PM Initialization, Device Probing and Removal

15
drivers/base/power/runtime.c
View File

@ -732,13 +732,16 @@ EXPORT_SYMBOL_GPL(pm_schedule_suspend);
* return immediately if it is larger than zero. Then carry out an idle
* notification, either synchronous or asynchronous.
*
* This routine may be called in atomic context if the RPM_ASYNC flag is set.
* This routine may be called in atomic context if the RPM_ASYNC flag is set,
* or if pm_runtime_irq_safe() has been called.
*/
int __pm_runtime_idle(struct device *dev, int rpmflags)
{
unsigned long flags;
int retval;
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
if (rpmflags & RPM_GET_PUT) {
if (!atomic_dec_and_test(&dev->power.usage_count))
return 0;
@ -761,13 +764,16 @@ EXPORT_SYMBOL_GPL(__pm_runtime_idle);
* return immediately if it is larger than zero. Then carry out a suspend,
* either synchronous or asynchronous.
*
* This routine may be called in atomic context if the RPM_ASYNC flag is set.
* This routine may be called in atomic context if the RPM_ASYNC flag is set,
* or if pm_runtime_irq_safe() has been called.
*/
int __pm_runtime_suspend(struct device *dev, int rpmflags)
{
unsigned long flags;
int retval;
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
if (rpmflags & RPM_GET_PUT) {
if (!atomic_dec_and_test(&dev->power.usage_count))
return 0;
@ -789,13 +795,16 @@ EXPORT_SYMBOL_GPL(__pm_runtime_suspend);
* If the RPM_GET_PUT flag is set, increment the device's usage count. Then
* carry out a resume, either synchronous or asynchronous.
*
* This routine may be called in atomic context if the RPM_ASYNC flag is set.
* This routine may be called in atomic context if the RPM_ASYNC flag is set,
* or if pm_runtime_irq_safe() has been called.
*/
int __pm_runtime_resume(struct device *dev, int rpmflags)
{
unsigned long flags;
int retval;
might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
if (rpmflags & RPM_GET_PUT)
atomic_inc(&dev->power.usage_count);