lib: percpu_counter_set

Provide a method to set a percpu counter to a specified value.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index f7ac68c..c9708db 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -14,6 +14,20 @@
 static DEFINE_MUTEX(percpu_counters_lock);
 #endif
 
+void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
+{
+	int cpu;
+
+	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);
+}
+EXPORT_SYMBOL(percpu_counter_set);
+
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
 {
 	s64 count;