1 files changed, 37 insertions, 4 deletions

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index d025c83cd12a..8b919471472f 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -428,6 +428,24 @@ int netvsc_device_remove(struct hv_device *device)
         return 0;
 }
 
+
+#define RING_AVAIL_PERCENT_HIWATER 20
+#define RING_AVAIL_PERCENT_LOWATER 10
+
+/*
+ * Get the percentage of available bytes to write in the ring.
+ * The return value is in range from 0 to 100.
+ */
+static inline u32 hv_ringbuf_avail_percent(
+                struct hv_ring_buffer_info *ring_info)
+{
+        u32 avail_read, avail_write;
+
+        hv_get_ringbuffer_availbytes(ring_info, &avail_read, &avail_write);
+
+        return avail_write * 100 / ring_info->ring_datasize;
+}
+
 static void netvsc_send_completion(struct hv_device *device,
                                    struct vmpacket_descriptor *packet)
 {
@@ -455,6 +473,8 @@ static void netvsc_send_completion(struct hv_device *device,
                 complete(&net_device->channel_init_wait);
         } else if (nvsp_packet->hdr.msg_type ==
                    NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE) {
+                int num_outstanding_sends;
+
                 /* Get the send context */
                 nvsc_packet = (struct hv_netvsc_packet *)(unsigned long)
                         packet->trans_id;
@@ -463,10 +483,14 @@ static void netvsc_send_completion(struct hv_device *device,
                 nvsc_packet->completion.send.send_completion(
                         nvsc_packet->completion.send.send_completion_ctx);
 
-                atomic_dec(&net_device->num_outstanding_sends);
+                num_outstanding_sends =
+                        atomic_dec_return(&net_device->num_outstanding_sends);
 
-                if (netif_queue_stopped(ndev) && !net_device->start_remove)
-                        netif_wake_queue(ndev);
+                if (netif_queue_stopped(ndev) && !net_device->start_remove &&
+                        (hv_ringbuf_avail_percent(&device->channel->outbound)
+                        > RING_AVAIL_PERCENT_HIWATER ||
+                        num_outstanding_sends < 1))
+                                netif_wake_queue(ndev);
         } else {
                 netdev_err(ndev, "Unknown send completion packet type- "
                            "%d received!!\n", nvsp_packet->hdr.msg_type);
@@ -519,10 +543,19 @@ int netvsc_send(struct hv_device *device,
 
         if (ret == 0) {
                 atomic_inc(&net_device->num_outstanding_sends);
+                if (hv_ringbuf_avail_percent(&device->channel->outbound) <
+                        RING_AVAIL_PERCENT_LOWATER) {
+                        netif_stop_queue(ndev);
+                        if (atomic_read(&net_device->
+                                num_outstanding_sends) < 1)
+                                netif_wake_queue(ndev);
+                }
         } else if (ret == -EAGAIN) {
                 netif_stop_queue(ndev);
-                if (atomic_read(&net_device->num_outstanding_sends) < 1)
+                if (atomic_read(&net_device->num_outstanding_sends) < 1) {
                         netif_wake_queue(ndev);
+                        ret = -ENOSPC;
+                }
         } else {
                 netdev_err(ndev, "Unable to send packet %p ret %d\n",
                            packet, ret);