hv_netvsc: count multicast packets received

BugLink: http://bugs.launchpad.net/bugs/1650059

Useful for debugging issues with multicast and SR-IOV to keep track
of number of received multicast packets.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit f7ad75b7)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/net/hyperv/hyperv_net.h

@@ -649,6 +649,8 @@ struct multi_recv_comp {
 struct netvsc_stats {
 	u64 packets;
 	u64 bytes;
+	u64 broadcast;
+	u64 multicast;
 	struct u64_stats_sync syncp;
 };
 

drivers/net/hyperv/netvsc_drv.c

@@ -711,6 +711,11 @@ int netvsc_recv_callback(struct hv_device *device_obj,
 	u64_stats_update_begin(&rx_stats->syncp);
 	rx_stats->packets++;
 	rx_stats->bytes += packet->total_data_buflen;
+
+	if (skb->pkt_type == PACKET_BROADCAST)
+		++rx_stats->broadcast;
+	else if (skb->pkt_type == PACKET_MULTICAST)
+		++rx_stats->multicast;
 	u64_stats_update_end(&rx_stats->syncp);
 
 	/*
@@ -954,7 +959,7 @@ static struct rtnl_link_stats64 *netvsc_get_stats64(struct net_device *net,
 							    cpu);
 		struct netvsc_stats *rx_stats = per_cpu_ptr(ndev_ctx->rx_stats,
 							    cpu);
-		u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
+		u64 tx_packets, tx_bytes, rx_packets, rx_bytes, rx_multicast;
 		unsigned int start;
 
 		do {
@@ -967,12 +972,14 @@ static struct rtnl_link_stats64 *netvsc_get_stats64(struct net_device *net,
 			start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
 			rx_packets = rx_stats->packets;
 			rx_bytes = rx_stats->bytes;
+			rx_multicast = rx_stats->multicast + rx_stats->broadcast;
 		} while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
 
 		t->tx_bytes	+= tx_bytes;
 		t->tx_packets	+= tx_packets;
 		t->rx_bytes	+= rx_bytes;
 		t->rx_packets	+= rx_packets;
+		t->multicast	+= rx_multicast;
 	}
 
 	t->tx_dropped	= net->stats.tx_dropped;