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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Acked-by: Viresh 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
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0e3f649..6001369 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -887,7 +887,7 @@
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 @@
up_write(&policy->rwsem);
}
- put_online_cpus();
+ cpus_read_unlock();
return ret;
}
@@ -2441,7 +2441,7 @@
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) {
@@ -2473,9 +2473,10 @@
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_cpuslocked(CPUHP_AP_ONLINE_DYN,
+ "cpufreq:online",
+ cpuhp_cpufreq_online,
+ cpuhp_cpufreq_offline);
if (ret < 0)
goto err_if_unreg;
hp_online = ret;
@@ -2493,7 +2494,7 @@
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 @@
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;
}