Messages in this thread | | | Date | Mon, 24 Oct 2016 15:52:38 -0700 | From | Stephen Boyd <> | Subject | Re: [PATCH V2 2/8] PM / OPP: Don't use OPP structure outside of rcu protected section |
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On 10/20, Viresh Kumar wrote: > The OPP structure must not be used out of the rcu protected section. > Cache the values to be used in separate variables instead. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Was this found by visual inspection or through some static checker? Just curious.
> @@ -633,6 +634,14 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) > return ret; > } > > + if (IS_ERR(old_opp)) { > + old_u_volt = 0; > + } else { > + old_u_volt = old_opp->u_volt; > + old_u_volt_min = old_opp->u_volt_min; > + old_u_volt_max = old_opp->u_volt_max; > + } > + > u_volt = opp->u_volt; > u_volt_min = opp->u_volt_min; > u_volt_max = opp->u_volt_max; > @@ -677,9 +686,10 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) > __func__, old_freq); > restore_voltage: > /* This shouldn't harm even if the voltages weren't updated earlier */ > - if (!IS_ERR(old_opp)) > - _set_opp_voltage(dev, reg, old_opp->u_volt, > - old_opp->u_volt_min, old_opp->u_volt_max); > + if (old_u_volt) {
What if old_u_volt == 0 is valid? We could have another variable like 'valid' or something that we use to figure out if we should set values instead. Then this isn't a potential pitfall.
> + _set_opp_voltage(dev, reg, old_u_volt, old_u_volt_min, > + old_u_volt_max); > + } > > return ret; > }
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