netvsc: account for packets/bytes transmitted after completion

Most drivers do not increment transmit statistics until after the
transmit is completed. This will also be necessary for BQL support.

Slight additional complexity because the netvsc driver aggregates
multiple packets into one transmit.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/hyperv_net.h

@@ -137,8 +137,10 @@ struct hv_netvsc_packet {
 	u8 page_buf_cnt;
 
 	u16 q_idx;
-	u32 send_buf_index;
+	u16 total_packets;
 
+	u32 total_bytes;
+	u32 send_buf_index;
 	u32 total_data_buflen;
 };
 

drivers/net/hyperv/netvsc.c

@@ -611,15 +611,23 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 
 	/* Notify the layer above us */
 	if (likely(skb)) {
-		struct hv_netvsc_packet *nvsc_packet
+		const struct hv_netvsc_packet *packet
 			= (struct hv_netvsc_packet *)skb->cb;
-		u32 send_index = nvsc_packet->send_buf_index;
+		u32 send_index = packet->send_buf_index;
+		struct netvsc_stats *tx_stats;
 
 		if (send_index != NETVSC_INVALID_INDEX)
 			netvsc_free_send_slot(net_device, send_index);
-		q_idx = nvsc_packet->q_idx;
+		q_idx = packet->q_idx;
 		channel = incoming_channel;
 
+		tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
+
+		u64_stats_update_begin(&tx_stats->syncp);
+		tx_stats->packets += packet->total_packets;
+		tx_stats->bytes += packet->total_bytes;
+		u64_stats_update_end(&tx_stats->syncp);
+
 		dev_consume_skb_any(skb);
 	}
 
@@ -924,6 +932,11 @@ int netvsc_send(struct hv_device *device,
 			packet->total_data_buflen += msd_len;
 		}
 
+		if (msdp->pkt) {
+			packet->total_packets += msdp->pkt->total_packets;
+			packet->total_bytes += msdp->pkt->total_bytes;
+		}
+
 		if (msdp->skb)
 			dev_consume_skb_any(msdp->skb);
 

drivers/net/hyperv/netvsc_drv.c

@@ -364,7 +364,6 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	u32 rndis_msg_size;
 	struct rndis_per_packet_info *ppi;
 	u32 hash;
-	u32 skb_length;
 	struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
 	struct hv_page_buffer *pb = page_buf;
 
@@ -374,7 +373,6 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	 * more pages we try linearizing it.
 	 */
 
-	skb_length = skb->len;
 	num_data_pgs = netvsc_get_slots(skb) + 2;
 
 	if (unlikely(num_data_pgs > MAX_PAGE_BUFFER_COUNT)) {
@@ -407,6 +405,8 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	packet->q_idx = skb_get_queue_mapping(skb);
 
 	packet->total_data_buflen = skb->len;
+	packet->total_bytes = skb->len;
+	packet->total_packets = 1;
 
 	rndis_msg = (struct rndis_message *)skb->head;
 
@@ -517,15 +517,8 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	skb_tx_timestamp(skb);
 	ret = netvsc_send(net_device_ctx->device_ctx, packet,
 			  rndis_msg, &pb, skb);
-	if (likely(ret == 0)) {
-		struct netvsc_stats *tx_stats = this_cpu_ptr(net_device_ctx->tx_stats);
-
-		u64_stats_update_begin(&tx_stats->syncp);
-		tx_stats->packets++;
-		tx_stats->bytes += skb_length;
-		u64_stats_update_end(&tx_stats->syncp);
+	if (likely(ret == 0))
 		return NETDEV_TX_OK;
-	}
 
 	if (ret == -EAGAIN) {
 		++net_device_ctx->eth_stats.tx_busy;