On 19-01-21, 20:16, Dmitry Osipenko wrote:

19.01.2021 09:35, Viresh Kumar пишет:

quoted

+	mutex_lock(&opp_table->lock);
+	opp_table->set_opp_data = data;
+	if (opp_table->sod_supplies) {
+		data->old_opp.supplies = opp_table->sod_supplies;
+		data->new_opp.supplies = opp_table->sod_supplies +
+					 opp_table->regulator_count;
+	}
+	mutex_unlock(&opp_table->lock);

Why do we need all these locks in this patch?

In case dev_pm_opp_set_regulators() and
dev_pm_opp_register_set_opp_helper() get called at the same time.
Which can actually happen, though is a corner case.

The OPP API isn't thread-safe, these locks won't make the API
thread-safe.

I am not sure what you mean by that, can you please explain ?

At least both sod_supplies and set_opp() pointers should be
set and unset under the lock.

The ->set_opp pointer isn't getting used for a comparison and so
putting that inside a lock won't get us anything. We are only using
set_opp_data and sod_supplies for comparison at both the places and so
they need to be updated within the lock.

-- 
viresh