Messages in this thread | | | Date | Mon, 25 Jul 2016 13:12:52 +0800 | From | Jisheng Zhang <> | Subject | Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit |
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Dear Viresh,
On Fri, 22 Jul 2016 09:21:51 -0700 Viresh Kumar wrote:
> On 22-07-16, 20:42, Jisheng Zhang wrote: > > static int _set_opp_voltage(struct device *dev, struct regulator *reg, > > unsigned long u_volt, unsigned long u_volt_min, > > unsigned long u_volt_max) > > @@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) > > return -EINVAL; > > } > > > > - clk = _get_opp_clk(dev); > > - if (IS_ERR(clk)) > > + rcu_read_lock(); > > + > > + opp_table = _find_opp_table(dev); > > + if (IS_ERR(opp_table)) { > > + dev_err(dev, "%s: device opp doesn't exist\n", __func__); > > + rcu_read_unlock(); > > + return PTR_ERR(opp_table); > > + } > > + > > + clk = opp_table->clk; > > + if (IS_ERR(clk)) { > > + dev_err(dev, "%s: No clock available for the device\n", > > + __func__); > > + rcu_read_unlock(); > > return PTR_ERR(clk); > > + } > > + > > + rcu_read_unlock(); > > It is not _safe_ to use opp_table pointer after the rcu_read_unlock()
Oops, indeed. Thanks very much for pointing it out! Will fix it in v2, so it seems we can only reduce the call of _find_opp_table to twice.
Thanks, Jisheng
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