hv_netvsc: report stop_queue and wake_queue

Report the numbers of events for stop_queue and wake_queue in
ethtool stats.

Example:
ethtool -S eth0
NIC statistics:
	...
	stop_queue: 7
	wake_queue: 7
	...
Signed-off-by: Simon Xiao <sixiao@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/hyperv_net.h

@@ -686,6 +686,8 @@ struct netvsc_ethtool_stats {
 	unsigned long tx_busy;
 	unsigned long tx_send_full;
 	unsigned long rx_comp_busy;
+	unsigned long stop_queue;
+	unsigned long wake_queue;
 };
 
 struct netvsc_vf_pcpu_stats {

drivers/net/hyperv/netvsc.c

@@ -609,6 +609,7 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 {
 	struct sk_buff *skb = (struct sk_buff *)(unsigned long)desc->trans_id;
 	struct net_device *ndev = hv_get_drvdata(device);
+	struct net_device_context *ndev_ctx = netdev_priv(ndev);
 	struct vmbus_channel *channel = device->channel;
 	u16 q_idx = 0;
 	int queue_sends;
@@ -643,8 +644,10 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 
 	if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
 	    (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
-	     queue_sends < 1))
+	     queue_sends < 1)) {
 		netif_tx_wake_queue(netdev_get_tx_queue(ndev, q_idx));
+		ndev_ctx->eth_stats.wake_queue++;
+	}
 }
 
 static void netvsc_send_completion(struct netvsc_device *net_device,
@@ -749,6 +752,7 @@ static inline int netvsc_send_pkt(
 		&net_device->chan_table[packet->q_idx];
 	struct vmbus_channel *out_channel = nvchan->channel;
 	struct net_device *ndev = hv_get_drvdata(device);
+	struct net_device_context *ndev_ctx = netdev_priv(ndev);
 	struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
 	u64 req_id;
 	int ret;
@@ -789,12 +793,16 @@ static inline int netvsc_send_pkt(
 	if (ret == 0) {
 		atomic_inc_return(&nvchan->queue_sends);
 
-		if (ring_avail < RING_AVAIL_PERCENT_LOWATER)
+		if (ring_avail < RING_AVAIL_PERCENT_LOWATER) {
 			netif_tx_stop_queue(txq);
+			ndev_ctx->eth_stats.stop_queue++;
+		}
 	} else if (ret == -EAGAIN) {
 		netif_tx_stop_queue(txq);
+		ndev_ctx->eth_stats.stop_queue++;
 		if (atomic_read(&nvchan->queue_sends) < 1) {
 			netif_tx_wake_queue(txq);
+			ndev_ctx->eth_stats.wake_queue++;
 			ret = -ENOSPC;
 		}
 	} else {

drivers/net/hyperv/netvsc_drv.c

@@ -1126,6 +1126,8 @@ static const struct {
 	{ "tx_busy",	  offsetof(struct netvsc_ethtool_stats, tx_busy) },
 	{ "tx_send_full", offsetof(struct netvsc_ethtool_stats, tx_send_full) },
 	{ "rx_comp_busy", offsetof(struct netvsc_ethtool_stats, rx_comp_busy) },
+	{ "stop_queue", offsetof(struct netvsc_ethtool_stats, stop_queue) },
+	{ "wake_queue", offsetof(struct netvsc_ethtool_stats, wake_queue) },
 }, vf_stats[] = {
 	{ "vf_rx_packets", offsetof(struct netvsc_vf_pcpu_stats, rx_packets) },
 	{ "vf_rx_bytes",   offsetof(struct netvsc_vf_pcpu_stats, rx_bytes) },