[PATCH V3 net-next 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host

["K. Y. Srinivasan" <kys@microsoft.com>]

Based on the information given to this driver (via the xmit_more skb flag),
we can defer signaling the host if more packets are on the way. This will help
make the host more efficient since it can potentially process a larger batch of
packets. Implement this optimization.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
	v2: Fixed up indentation based on feedback from David Miller.
	v3: If the queue is stopped, deal with that condition: Eric Dumazet <eric.dumazet@gmail.com>
 drivers/net/hyperv/netvsc.c     |   20 ++++++++++++--------
 drivers/net/hyperv/netvsc_drv.c |    2 ++
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ea091bc..36fef17 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -743,6 +743,7 @@ static inline int netvsc_send_pkt(
 	u64 req_id;
 	int ret;
 	struct hv_page_buffer *pgbuf;
+	u32 vmbus_flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 
 	nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
 	if (packet->is_data_pkt) {
@@ -772,19 +773,22 @@ static inline int netvsc_send_pkt(
 	if (packet->page_buf_cnt) {
 		pgbuf = packet->cp_partial ? packet->page_buf +
 			packet->rmsg_pgcnt : packet->page_buf;
-		ret = vmbus_sendpacket_pagebuffer(out_channel,
-						  pgbuf,
-						  packet->page_buf_cnt,
-						  &nvmsg,
-						  sizeof(struct nvsp_message),
-						  req_id);
+		ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
+						      pgbuf,
+						      packet->page_buf_cnt,
+						      &nvmsg,
+						      sizeof(struct
+							     nvsp_message),
+						      req_id,
+						      vmbus_flags,
+						      !packet->xmit_more);
 	} else {
-		ret = vmbus_sendpacket(
+		ret = vmbus_sendpacket_ctl(
 				out_channel, &nvmsg,
 				sizeof(struct nvsp_message),
 				req_id,
 				VM_PKT_DATA_INBAND,
-				VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+				vmbus_flags, !packet->xmit_more);
 	}
 
 	if (ret == 0) {
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 5993c7e..4efaa6e 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -435,6 +435,8 @@ check_size:
 	packet->page_buf = page_buf;
 
 	packet->q_idx = skb_get_queue_mapping(skb);
+	if (netif_tx_queue_stopped(netdev_get_tx_queue(net, packet->q_idx)))
+		packet->xmit_more = false;
 
 	packet->is_data_pkt = true;
 	packet->total_data_buflen = skb->len;
-- 
1.7.4.1