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authorColin Cross <ccross@android.com>2011-08-08 23:39:36 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-08-14 13:35:52 +0200
commit311aab73d273eb22be976055f6cab224f7279d5e (patch)
tree14ef310eb77cac8d85c85b3ed006713e4602ec8f
parent17f2ae7f677f023997e02fd2ebabd90ea2a0390d (diff)
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>
-rw-r--r--Documentation/power/runtime_pm.txt1
-rw-r--r--drivers/base/power/runtime.c15
2 files changed, 13 insertions, 3 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 4ce5450ab6e8..62f37bc3866f 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -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
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index acb3f83b8079..04e18abb50bb 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -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);