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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 5edc901..b9df9ed 100644 (file)
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -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 */

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 28f2c33..f087105 100644 (file)
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -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