[PATCH v5 12/23] PM: EM: Add helpers to read under RCU lock the EM table

Lukasz Luba
2023-11-29T11:09:33Z

To use the runtime modifiable EM table there is a need to use RCU
read locking properly. Add helper functions for the device drivers and
frameworks to make sure it's done properly.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
---
include/linux/energy_model.h | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h
index 520a8c8ad849..ae3ccc8b9f44 100644
--- a/include/linux/energy_model.h
+++ b/include/linux/energy_model.h
@@ -341,6 +341,20 @@ static inline int em_pd_nr_perf_states(struct em_perf_domain *pd)
return pd->nr_perf_states;
}

+static inline struct em_perf_state *em_get_table(struct em_perf_domain *pd)
+{
+ struct em_perf_table __rcu *runtime_table;
+
+ rcu_read_lock();
+ runtime_table = rcu_dereference(pd->runtime_table);
+ return runtime_table->state;
+}
+
+static inline void em_put_table(void)
+{
+ rcu_read_unlock();
+}
+
#else
struct em_data_callback {};
#define EM_ADV_DATA_CB(_active_power_cb, _cost_cb) { }
@@ -387,6 +401,11 @@ int em_dev_update_perf_domain(struct device *dev,
{
return -EINVAL;
}
+static inline struct em_perf_state *em_get_table(struct em_perf_domain *pd)
+{
+ return NULL;
+}
+static inline void em_put_table(void) {}
#endif

#endif
--
2.25.1