On Sat, Apr 15, 2017 at 7:01 PM, Thomas Gleixner <t...@linutronix.de> wrote: > From: Sebastian Andrzej Siewior <bige...@linutronix.de> > > cpufreq holds get_online_cpus() while invoking cpuhp_setup_state_nocalls() > to make subsys_interface_register() and the registration of hotplug calls > atomic versus cpu hotplug. > > cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is > correct, but prevents the conversion of the hotplug locking to a percpu > rwsem. > > Use cpuhp_setup_state_nocalls_locked() to avoid the nested call. > > Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de> > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > Cc: "Rafael J. Wysocki" <r...@rjwysocki.net> > Cc: Viresh Kumar <viresh.ku...@linaro.org> > Cc: linux...@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > --- > drivers/cpufreq/cpufreq.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -2473,9 +2473,10 @@ int cpufreq_register_driver(struct cpufr > goto err_if_unreg; > } > > - ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online", > - cpuhp_cpufreq_online, > - cpuhp_cpufreq_offline); > + ret = cpuhp_setup_state_nocalls_locked(CPUHP_AP_ONLINE_DYN, > + "cpufreq:online", > + cpuhp_cpufreq_online, > + cpuhp_cpufreq_offline); > if (ret < 0) > goto err_if_unreg; > hp_online = ret; > @@ -2519,7 +2520,7 @@ int cpufreq_unregister_driver(struct cpu > get_online_cpus(); > subsys_interface_unregister(&cpufreq_interface); > remove_boost_sysfs_file(); > - cpuhp_remove_state_nocalls(hp_online); > + cpuhp_remove_state_nocalls_locked(hp_online); > > write_lock_irqsave(&cpufreq_driver_lock, flags); > > >
