netvsc: use hv_get_bytes_to_read

Don't need need to look at write space in netvsc_close.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -120,7 +120,7 @@ static int netvsc_close(struct net_device *net)
 	struct net_device_context *net_device_ctx = netdev_priv(net);
 	struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
 	int ret;
-	u32 aread, awrite, i, msec = 10, retry = 0, retry_max = 20;
+	u32 aread, i, msec = 10, retry = 0, retry_max = 20;
 	struct vmbus_channel *chn;
 
 	netif_tx_disable(net);
@@ -141,15 +141,11 @@ static int netvsc_close(struct net_device *net)
 			if (!chn)
 				continue;
 
-			hv_get_ringbuffer_availbytes(&chn->inbound, &aread,
-						     &awrite);
-
+			aread = hv_get_bytes_to_read(&chn->inbound);
 			if (aread)
 				break;
 
-			hv_get_ringbuffer_availbytes(&chn->outbound, &aread,
-						     &awrite);
-
+			aread = hv_get_bytes_to_read(&chn->outbound);
 			if (aread)
 				break;
 		}