[PATCH v3 2/4] PM / QoS: add lockless read for flags

[Kevin Hilman (TI)]

Add a lockless read for QoS flags similar to the lockless read for
resume latency (dev_pm_qos_raw_resume_latency) which may be called
from atomic context (e.g. genpd governors running under a raw spinlock
or in the syscore suspend path), where taking that sleeping lock would
be invalid on PREEMPT_RT.

Signed-off-by: Kevin Hilman (TI) <khilman@xxxxxxxxxxxx>
---
 include/linux/pm_qos.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index aededda52b6b..439a9e779d81 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -219,6 +219,12 @@ static inline s32 dev_pm_qos_raw_resume_latency(struct device *dev)
 		PM_QOS_RESUME_LATENCY_NO_CONSTRAINT :
 		pm_qos_read_value(&dev->power.qos->resume_latency);
 }
+
+static inline s32 dev_pm_qos_raw_flags(struct device *dev)
+{
+	return IS_ERR_OR_NULL(dev->power.qos) ?
+		0 : READ_ONCE(dev->power.qos->flags.effective_flags);
+}
 #else
 static inline enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev,
 							  s32 mask)
@@ -300,6 +306,7 @@ static inline s32 dev_pm_qos_raw_resume_latency(struct device *dev)
 {
 	return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
 }
+static inline s32 dev_pm_qos_raw_flags(struct device *dev) { return 0; }
 #endif
 
 static inline int freq_qos_request_active(struct freq_qos_request *req)

-- 
2.47.3