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Commit f032a450 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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locking, percpu_counter: Annotate ::lock as raw 



The percpu_counter::lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ec484608

include/linux/percpu_counter.h

+1 −1
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
#ifdef CONFIG_SMP



struct percpu_counter {

	spinlock_t lock;

	raw_spinlock_t lock;

	s64 count;

#ifdef CONFIG_HOTPLUG_CPU

	struct list_head list;	/* All percpu_counters are on a list */

lib/percpu_counter.c

+9 −9
Original line number Diff line number Diff line
@@ -59,13 +59,13 @@ void percpu_counter_set(struct percpu_counter *fbc, s64 amount) 
{

	int cpu;



	spin_lock(&fbc->lock);

	raw_spin_lock(&fbc->lock);

	for_each_possible_cpu(cpu) {

		s32 *pcount = per_cpu_ptr(fbc->counters, cpu);

		*pcount = 0;

	}

	fbc->count = amount;

	spin_unlock(&fbc->lock);

	raw_spin_unlock(&fbc->lock);

}

EXPORT_SYMBOL(percpu_counter_set);
@@ -76,10 +76,10 @@ void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch) 
	preempt_disable();

	count = __this_cpu_read(*fbc->counters) + amount;

	if (count >= batch || count <= -batch) {

		spin_lock(&fbc->lock);

		raw_spin_lock(&fbc->lock);

		fbc->count += count;

		__this_cpu_write(*fbc->counters, 0);

		spin_unlock(&fbc->lock);

		raw_spin_unlock(&fbc->lock);

	} else {

		__this_cpu_write(*fbc->counters, count);

	}
@@ -96,13 +96,13 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc) 
	s64 ret;

	int cpu;



	spin_lock(&fbc->lock);

	raw_spin_lock(&fbc->lock);

	ret = fbc->count;

	for_each_online_cpu(cpu) {

		s32 *pcount = per_cpu_ptr(fbc->counters, cpu);

		ret += *pcount;

	}

	spin_unlock(&fbc->lock);

	raw_spin_unlock(&fbc->lock);

	return ret;

}

EXPORT_SYMBOL(__percpu_counter_sum);
@@ -110,7 +110,7 @@ EXPORT_SYMBOL(__percpu_counter_sum); 
int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,

			  struct lock_class_key *key)

{

	spin_lock_init(&fbc->lock);

	raw_spin_lock_init(&fbc->lock);

	lockdep_set_class(&fbc->lock, key);

	fbc->count = amount;

	fbc->counters = alloc_percpu(s32);
@@ -173,11 +173,11 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb, 
		s32 *pcount;

		unsigned long flags;



		spin_lock_irqsave(&fbc->lock, flags);

		raw_spin_lock_irqsave(&fbc->lock, flags);

		pcount = per_cpu_ptr(fbc->counters, cpu);

		fbc->count += *pcount;

		*pcount = 0;

		spin_unlock_irqrestore(&fbc->lock, flags);

		raw_spin_unlock_irqrestore(&fbc->lock, flags);

	}

	mutex_unlock(&percpu_counters_lock);

#endif