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 all 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@xxxxxxxxxxx>
---
Documentation/power/runtime_pm.txt | 1 +
drivers/base/power/runtime.c | 15 ++++++++++++---
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index c291233..1ad507c 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -469,6 +469,7 @@ pm_runtime_resume()
pm_runtime_get_sync()
pm_runtime_put_sync()
pm_runtime_put_sync_suspend()
+pm_runtime_put_sync_autosuspend()
5. Run-time PM Initialization, Device Probing and Removal
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 2e746f8..f3d8583 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -731,13 +731,16 @@ 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;
@@ -760,13 +763,16 @@ 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;
@@ -788,13 +794,16 @@ 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);
--
1.7.4.1
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