hv_netvsc: pass netvsc_device to receive callback

The netvsc_receive_callback function was using RCU to find the
appropriate underlying netvsc_device. Since calling function already
had that pointer, this was unnecessary.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3997c2d..5ab8161 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -739,34 +739,26 @@
  * "wire" on the specified device.
  */
 int netvsc_recv_callback(struct net_device *net,
+			 struct netvsc_device *net_device,
 			 struct vmbus_channel *channel,
 			 void  *data, u32 len,
 			 const struct ndis_tcp_ip_checksum_info *csum_info,
 			 const struct ndis_pkt_8021q_info *vlan)
 {
 	struct net_device_context *net_device_ctx = netdev_priv(net);
-	struct netvsc_device *net_device;
 	u16 q_idx = channel->offermsg.offer.sub_channel_index;
-	struct netvsc_channel *nvchan;
+	struct netvsc_channel *nvchan = &net_device->chan_table[q_idx];
 	struct sk_buff *skb;
 	struct netvsc_stats *rx_stats;
 
 	if (net->reg_state != NETREG_REGISTERED)
 		return NVSP_STAT_FAIL;
 
-	rcu_read_lock();
-	net_device = rcu_dereference(net_device_ctx->nvdev);
-	if (unlikely(!net_device))
-		goto drop;
-
-	nvchan = &net_device->chan_table[q_idx];
-
 	/* Allocate a skb - TODO direct I/O to pages? */
 	skb = netvsc_alloc_recv_skb(net, &nvchan->napi,
 				    csum_info, vlan, data, len);
 	if (unlikely(!skb)) {
 		++net_device_ctx->eth_stats.rx_no_memory;
-drop:
 		rcu_read_unlock();
 		return NVSP_STAT_FAIL;
 	}
@@ -790,8 +782,6 @@
 	u64_stats_update_end(&rx_stats->syncp);
 
 	napi_gro_receive(&nvchan->napi, skb);
-	rcu_read_unlock();
-
 	return 0;
 }