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Commit 65edc68c authored by Chandra Seetharaman's avatar Chandra Seetharaman Committed by Linus Torvalds
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[PATCH] cpu hotplug: make [un]register_cpu_notifier init time only 



CPUs come online only at init time (unless CONFIG_HOTPLUG_CPU is defined).
So, cpu_notifier functionality need to be available only at init time.

This patch makes register_cpu_notifier() available only at init time, unless
CONFIG_HOTPLUG_CPU is defined.

This patch exports register_cpu_notifier() and unregister_cpu_notifier() only
if CONFIG_HOTPLUG_CPU is defined.

Signed-off-by: default avatarChandra Seetharaman <sekharan@us.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 054cc8a2

drivers/cpufreq/cpufreq.c

+5 −3
Original line number Diff line number Diff line
@@ -1497,7 +1497,8 @@ int cpufreq_update_policy(unsigned int cpu) 
}

EXPORT_SYMBOL(cpufreq_update_policy);



static int __cpuinit cpufreq_cpu_callback(struct notifier_block *nfb,

#ifdef CONFIG_HOTPLUG_CPU

static int cpufreq_cpu_callback(struct notifier_block *nfb,

					unsigned long action, void *hcpu)

{

	unsigned int cpu = (unsigned long)hcpu;
@@ -1536,6 +1537,7 @@ static struct notifier_block cpufreq_cpu_notifier = 
{

    .notifier_call = cpufreq_cpu_callback,

};

#endif /* CONFIG_HOTPLUG_CPU */



/*********************************************************************

 *               REGISTER / UNREGISTER CPUFREQ DRIVER                *
@@ -1596,7 +1598,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) 
	}



	if (!ret) {

		register_cpu_notifier(&cpufreq_cpu_notifier);

		register_hotcpu_notifier(&cpufreq_cpu_notifier);

		dprintk("driver %s up and running\n", driver_data->name);

		cpufreq_debug_enable_ratelimit();

	}
@@ -1628,7 +1630,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) 
	dprintk("unregistering driver %s\n", driver->name);



	sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);

	unregister_cpu_notifier(&cpufreq_cpu_notifier);

	unregister_hotcpu_notifier(&cpufreq_cpu_notifier);



	spin_lock_irqsave(&cpufreq_driver_lock, flags);

	cpufreq_driver = NULL;

drivers/cpufreq/cpufreq_stats.c

+2 −2
Original line number Diff line number Diff line
@@ -350,7 +350,7 @@ __init cpufreq_stats_init(void) 
		return ret;

	}



	register_cpu_notifier(&cpufreq_stat_cpu_notifier);

	register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

	lock_cpu_hotplug();

	for_each_online_cpu(cpu) {

		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_ONLINE,
@@ -368,7 +368,7 @@ __exit cpufreq_stats_exit(void) 
			CPUFREQ_POLICY_NOTIFIER);

	cpufreq_unregister_notifier(&notifier_trans_block,

			CPUFREQ_TRANSITION_NOTIFIER);

	unregister_cpu_notifier(&cpufreq_stat_cpu_notifier);

	unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);

	lock_cpu_hotplug();

	for_each_online_cpu(cpu) {

		cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_DEAD,

include/linux/cpu.h

+6 −0
Original line number Diff line number Diff line
@@ -41,7 +41,13 @@ struct notifier_block; 
#ifdef CONFIG_SMP

/* Need to know about CPUs going up/down? */

extern int register_cpu_notifier(struct notifier_block *nb);

#ifdef CONFIG_HOTPLUG_CPU

extern void unregister_cpu_notifier(struct notifier_block *nb);

#else

static inline void unregister_cpu_notifier(struct notifier_block *nb)

{

}

#endif

extern int current_in_cpu_hotplug(void);



int cpu_up(unsigned int cpu);

kernel/cpu.c

+5 −3
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 
/* This protects CPUs going up and down... */

static DEFINE_MUTEX(cpucontrol);



static BLOCKING_NOTIFIER_HEAD(cpu_chain);

static __cpuinitdata BLOCKING_NOTIFIER_HEAD(cpu_chain);



#ifdef CONFIG_HOTPLUG_CPU

static struct task_struct *lock_cpu_hotplug_owner;
@@ -69,10 +69,13 @@ EXPORT_SYMBOL_GPL(lock_cpu_hotplug_interruptible); 
#endif	/* CONFIG_HOTPLUG_CPU */



/* Need to know about CPUs going up/down? */

int register_cpu_notifier(struct notifier_block *nb)

int __cpuinit register_cpu_notifier(struct notifier_block *nb)

{

	return blocking_notifier_chain_register(&cpu_chain, nb);

}



#ifdef CONFIG_HOTPLUG_CPU



EXPORT_SYMBOL(register_cpu_notifier);



void unregister_cpu_notifier(struct notifier_block *nb)
@@ -81,7 +84,6 @@ void unregister_cpu_notifier(struct notifier_block *nb) 
}

EXPORT_SYMBOL(unregister_cpu_notifier);



#ifdef CONFIG_HOTPLUG_CPU

static inline void check_for_tasks(int cpu)

{

	struct task_struct *p;