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Commit ebd8fef3 authored by Tejun Heo's avatar Tejun Heo
Browse files

percpu_counter: make percpu_counters_lock irq-safe 



percpu_counter is scheduled to grow @gfp support to allow atomic
initialization.  This patch makes percpu_counters_lock irq-safe so
that it can be safely used from atomic contexts.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 1a4d7607

lib/percpu_counter.c

+10 −6
Original line number Diff line number Diff line
@@ -115,6 +115,8 @@ EXPORT_SYMBOL(__percpu_counter_sum); 
int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,

			  struct lock_class_key *key)

{

	unsigned long flags __maybe_unused;



	raw_spin_lock_init(&fbc->lock);

	lockdep_set_class(&fbc->lock, key);

	fbc->count = amount;
@@ -126,9 +128,9 @@ int __percpu_counter_init(struct percpu_counter *fbc, s64 amount, 


#ifdef CONFIG_HOTPLUG_CPU

	INIT_LIST_HEAD(&fbc->list);

	spin_lock(&percpu_counters_lock);

	spin_lock_irqsave(&percpu_counters_lock, flags);

	list_add(&fbc->list, &percpu_counters);

	spin_unlock(&percpu_counters_lock);

	spin_unlock_irqrestore(&percpu_counters_lock, flags);

#endif

	return 0;

}
@@ -136,15 +138,17 @@ EXPORT_SYMBOL(__percpu_counter_init); 


void percpu_counter_destroy(struct percpu_counter *fbc)

{

	unsigned long flags __maybe_unused;



	if (!fbc->counters)

		return;



	debug_percpu_counter_deactivate(fbc);



#ifdef CONFIG_HOTPLUG_CPU

	spin_lock(&percpu_counters_lock);

	spin_lock_irqsave(&percpu_counters_lock, flags);

	list_del(&fbc->list);

	spin_unlock(&percpu_counters_lock);

	spin_unlock_irqrestore(&percpu_counters_lock, flags);

#endif

	free_percpu(fbc->counters);

	fbc->counters = NULL;
@@ -173,7 +177,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb, 
		return NOTIFY_OK;



	cpu = (unsigned long)hcpu;

	spin_lock(&percpu_counters_lock);

	spin_lock_irq(&percpu_counters_lock);

	list_for_each_entry(fbc, &percpu_counters, list) {

		s32 *pcount;

		unsigned long flags;
@@ -184,7 +188,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb, 
		*pcount = 0;

		raw_spin_unlock_irqrestore(&fbc->lock, flags);

	}

	spin_unlock(&percpu_counters_lock);

	spin_unlock_irq(&percpu_counters_lock);

#endif

	return NOTIFY_OK;

}