* [PATCH] cpufreq: Lock CPU online/offline in cpufreq_register_driver()
@ 2015-07-29 23:45 Rafael J. Wysocki
2015-07-30 5:48 ` Viresh Kumar
0 siblings, 1 reply; 3+ messages in thread
From: Rafael J. Wysocki @ 2015-07-29 23:45 UTC (permalink / raw)
To: Linux PM list; +Cc: Linux Kernel Mailing List, Viresh Kumar, Russell King
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To protect against races with concurrent CPU online/offline, call
get_online_cpus() before registering a cpufreq driver.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/cpufreq.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -2471,10 +2471,14 @@ int cpufreq_register_driver(struct cpufr
pr_debug("trying to register driver %s\n", driver_data->name);
+ /* Protect against concurrent CPU online/offline. */
+ get_online_cpus();
+
write_lock_irqsave(&cpufreq_driver_lock, flags);
if (cpufreq_driver) {
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return -EEXIST;
+ ret = -EEXIST;
+ goto out;
}
cpufreq_driver = driver_data;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -2513,7 +2517,10 @@ int cpufreq_register_driver(struct cpufr
register_hotcpu_notifier(&cpufreq_cpu_notifier);
pr_debug("driver %s up and running\n", driver_data->name);
- return 0;
+out:
+ put_online_cpus();
+ return ret;
+
err_if_unreg:
subsys_interface_unregister(&cpufreq_interface);
err_boost_unreg:
@@ -2523,7 +2530,7 @@ err_null_driver:
write_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
- return ret;
+ goto out;
}
EXPORT_SYMBOL_GPL(cpufreq_register_driver);
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] cpufreq: Lock CPU online/offline in cpufreq_register_driver()
2015-07-29 23:45 [PATCH] cpufreq: Lock CPU online/offline in cpufreq_register_driver() Rafael J. Wysocki
@ 2015-07-30 5:48 ` Viresh Kumar
2015-07-30 7:12 ` Viresh Kumar
0 siblings, 1 reply; 3+ messages in thread
From: Viresh Kumar @ 2015-07-30 5:48 UTC (permalink / raw)
To: Rafael J. Wysocki; +Cc: Linux PM list, Linux Kernel Mailing List, Russell King
On 30-07-15, 01:45, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> To protect against races with concurrent CPU online/offline, call
> get_online_cpus() before registering a cpufreq driver.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/cpufreq/cpufreq.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> Index: linux-pm/drivers/cpufreq/cpufreq.c
> ===================================================================
> --- linux-pm.orig/drivers/cpufreq/cpufreq.c
> +++ linux-pm/drivers/cpufreq/cpufreq.c
> @@ -2471,10 +2471,14 @@ int cpufreq_register_driver(struct cpufr
>
> pr_debug("trying to register driver %s\n", driver_data->name);
>
> + /* Protect against concurrent CPU online/offline. */
> + get_online_cpus();
> +
> write_lock_irqsave(&cpufreq_driver_lock, flags);
> if (cpufreq_driver) {
> write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> - return -EEXIST;
> + ret = -EEXIST;
> + goto out;
> }
> cpufreq_driver = driver_data;
> write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> @@ -2513,7 +2517,10 @@ int cpufreq_register_driver(struct cpufr
> register_hotcpu_notifier(&cpufreq_cpu_notifier);
> pr_debug("driver %s up and running\n", driver_data->name);
>
> - return 0;
> +out:
> + put_online_cpus();
> + return ret;
> +
> err_if_unreg:
> subsys_interface_unregister(&cpufreq_interface);
> err_boost_unreg:
> @@ -2523,7 +2530,7 @@ err_null_driver:
> write_lock_irqsave(&cpufreq_driver_lock, flags);
> cpufreq_driver = NULL;
> write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> - return ret;
> + goto out;
> }
> EXPORT_SYMBOL_GPL(cpufreq_register_driver);
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] cpufreq: Lock CPU online/offline in cpufreq_register_driver()
2015-07-30 5:48 ` Viresh Kumar
@ 2015-07-30 7:12 ` Viresh Kumar
0 siblings, 0 replies; 3+ messages in thread
From: Viresh Kumar @ 2015-07-30 7:12 UTC (permalink / raw)
To: Rafael J. Wysocki; +Cc: Linux PM list, Linux Kernel Mailing List, Russell King
Fixing Russell's id.
On 30-07-15, 11:18, Viresh Kumar wrote:
> On 30-07-15, 01:45, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > To protect against races with concurrent CPU online/offline, call
> > get_online_cpus() before registering a cpufreq driver.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> > drivers/cpufreq/cpufreq.c | 13 ++++++++++---
> > 1 file changed, 10 insertions(+), 3 deletions(-)
> >
> > Index: linux-pm/drivers/cpufreq/cpufreq.c
> > ===================================================================
> > --- linux-pm.orig/drivers/cpufreq/cpufreq.c
> > +++ linux-pm/drivers/cpufreq/cpufreq.c
> > @@ -2471,10 +2471,14 @@ int cpufreq_register_driver(struct cpufr
> >
> > pr_debug("trying to register driver %s\n", driver_data->name);
> >
> > + /* Protect against concurrent CPU online/offline. */
> > + get_online_cpus();
> > +
> > write_lock_irqsave(&cpufreq_driver_lock, flags);
> > if (cpufreq_driver) {
> > write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> > - return -EEXIST;
> > + ret = -EEXIST;
> > + goto out;
> > }
> > cpufreq_driver = driver_data;
> > write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> > @@ -2513,7 +2517,10 @@ int cpufreq_register_driver(struct cpufr
> > register_hotcpu_notifier(&cpufreq_cpu_notifier);
> > pr_debug("driver %s up and running\n", driver_data->name);
> >
> > - return 0;
> > +out:
> > + put_online_cpus();
> > + return ret;
> > +
> > err_if_unreg:
> > subsys_interface_unregister(&cpufreq_interface);
> > err_boost_unreg:
> > @@ -2523,7 +2530,7 @@ err_null_driver:
> > write_lock_irqsave(&cpufreq_driver_lock, flags);
> > cpufreq_driver = NULL;
> > write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> > - return ret;
> > + goto out;
> > }
> > EXPORT_SYMBOL_GPL(cpufreq_register_driver);
>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> --
> viresh
--
viresh
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-07-29 23:45 [PATCH] cpufreq: Lock CPU online/offline in cpufreq_register_driver() Rafael J. Wysocki
2015-07-30 5:48 ` Viresh Kumar
2015-07-30 7:12 ` Viresh Kumar
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