powerpc/perf/hv-24x7: Define update_event_count()

Move the code to update an event count into a new function,
update_event_count().

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/perf/hv-24x7.c

@@ -1172,16 +1172,22 @@ static u64 h_24x7_get_value(struct perf_event *event)
 	return ct;
 }
 
-static void h_24x7_event_read(struct perf_event *event)
+static void update_event_count(struct perf_event *event, u64 now)
 {
 	s64 prev;
-	u64 now;
 
-	now = h_24x7_get_value(event);
 	prev = local64_xchg(&event->hw.prev_count, now);
 	local64_add(now - prev, &event->count);
 }
 
+static void h_24x7_event_read(struct perf_event *event)
+{
+	u64 now;
+
+	now = h_24x7_get_value(event);
+	update_event_count(event, now);
+}
+
 static void h_24x7_event_start(struct perf_event *event, int flags)
 {
 	if (flags & PERF_EF_RELOAD)