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Commit a92551e4 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
Browse files

cpufreq: Use cpuhp_setup_state_nocalls_cpuslocked() 



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/remove_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatar"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081547.731628408@linutronix.de
parent 547efead

drivers/cpufreq/cpufreq.c

+11 −10
Original line number Diff line number Diff line
@@ -887,7 +887,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, 
	struct freq_attr *fattr = to_attr(attr);

	ssize_t ret = -EINVAL;



	get_online_cpus();

	cpus_read_lock();



	if (cpu_online(policy->cpu)) {

		down_write(&policy->rwsem);
@@ -895,7 +895,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, 
		up_write(&policy->rwsem);

	}



	put_online_cpus();

	cpus_read_unlock();



	return ret;

}
@@ -2441,7 +2441,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) 
	pr_debug("trying to register driver %s\n", driver_data->name);



	/* Protect against concurrent CPU online/offline. */

	get_online_cpus();

	cpus_read_lock();



	write_lock_irqsave(&cpufreq_driver_lock, flags);

	if (cpufreq_driver) {
@@ -2473,7 +2473,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) 
		goto err_if_unreg;

	}



	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online",

	ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,

						   "cpufreq:online",

						   cpuhp_cpufreq_online,

						   cpuhp_cpufreq_offline);

	if (ret < 0)
@@ -2493,7 +2494,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) 
	cpufreq_driver = NULL;

	write_unlock_irqrestore(&cpufreq_driver_lock, flags);

out:

	put_online_cpus();

	cpus_read_unlock();

	return ret;

}

EXPORT_SYMBOL_GPL(cpufreq_register_driver);
@@ -2516,17 +2517,17 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) 
	pr_debug("unregistering driver %s\n", driver->name);



	/* Protect against concurrent cpu hotplug */

	get_online_cpus();

	cpus_read_lock();

	subsys_interface_unregister(&cpufreq_interface);

	remove_boost_sysfs_file();

	cpuhp_remove_state_nocalls(hp_online);

	cpuhp_remove_state_nocalls_cpuslocked(hp_online);



	write_lock_irqsave(&cpufreq_driver_lock, flags);



	cpufreq_driver = NULL;



	write_unlock_irqrestore(&cpufreq_driver_lock, flags);

	put_online_cpus();

	cpus_read_unlock();



	return 0;

}