gen_stats: Add gnet_stats_add_queue().

This function will replace __gnet_stats_copy_queue(). It reads all
arguments and adds them into the passed gnet_stats_queue argument.
In contrast to __gnet_stats_copy_queue() it also copies the qlen member.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/gen_stats.h

@@ -62,6 +62,9 @@ int gnet_stats_copy_queue(struct gnet_dump *d,
 void __gnet_stats_copy_queue(struct gnet_stats_queue *qstats,
 			     const struct gnet_stats_queue __percpu *cpu_q,
 			     const struct gnet_stats_queue *q, __u32 qlen);
+void gnet_stats_add_queue(struct gnet_stats_queue *qstats,
+			  const struct gnet_stats_queue __percpu *cpu_q,
+			  const struct gnet_stats_queue *q);
 int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len);
 
 int gnet_stats_finish_copy(struct gnet_dump *d);

net/core/gen_stats.c

@@ -321,6 +321,38 @@ void __gnet_stats_copy_queue(struct gnet_stats_queue *qstats,
 }
 EXPORT_SYMBOL(__gnet_stats_copy_queue);
 
+static void gnet_stats_add_queue_cpu(struct gnet_stats_queue *qstats,
+				     const struct gnet_stats_queue __percpu *q)
+{
+	int i;
+
+	for_each_possible_cpu(i) {
+		const struct gnet_stats_queue *qcpu = per_cpu_ptr(q, i);
+
+		qstats->qlen += qcpu->backlog;
+		qstats->backlog += qcpu->backlog;
+		qstats->drops += qcpu->drops;
+		qstats->requeues += qcpu->requeues;
+		qstats->overlimits += qcpu->overlimits;
+	}
+}
+
+void gnet_stats_add_queue(struct gnet_stats_queue *qstats,
+			  const struct gnet_stats_queue __percpu *cpu,
+			  const struct gnet_stats_queue *q)
+{
+	if (cpu) {
+		gnet_stats_add_queue_cpu(qstats, cpu);
+	} else {
+		qstats->qlen += q->qlen;
+		qstats->backlog += q->backlog;
+		qstats->drops += q->drops;
+		qstats->requeues += q->requeues;
+		qstats->overlimits += q->overlimits;
+	}
+}
+EXPORT_SYMBOL(gnet_stats_add_queue);
+
 /**
  * gnet_stats_copy_queue - copy queue statistics into statistics TLV
  * @d: dumping handle