From: Stephen Hemminger <stephen@networkplumber.org>
Date: Tue, 12 Dec 2017 16:48:38 -0800
Patch-mainline: v4.16-rc1
Subject: hv_netvsc: pass netvsc_device to receive callback
Git-commit: 345ac08990b8365294f9756da806f357c239d758
References: fate#323887

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>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/net/hyperv/hyperv_net.h   |  1 +
 drivers/net/hyperv/netvsc_drv.c   | 14 ++------------
 drivers/net/hyperv/rndis_filter.c |  7 +++++--
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -202,6 +202,7 @@ int netvsc_send(struct net_device_context *ndc,
 void netvsc_linkstatus_callback(struct net_device *net,
 				struct rndis_message *resp);
 int netvsc_recv_callback(struct net_device *net,
+			 struct netvsc_device *nvdev,
 			 struct vmbus_channel *channel,
 			 void  *data, u32 len,
 			 const struct ndis_tcp_ip_checksum_info *csum_info,
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -739,34 +739,26 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
  * "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 @@ drop:
 	u64_stats_update_end(&rx_stats->syncp);
 
 	napi_gro_receive(&nvchan->napi, skb);
-	rcu_read_unlock();
-
 	return 0;
 }
 
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -352,6 +352,7 @@ static inline void *rndis_get_ppi(struct rndis_packet *rpkt, u32 type)
 }
 
 static int rndis_filter_receive_data(struct net_device *ndev,
+				     struct netvsc_device *nvdev,
 				     struct rndis_device *dev,
 				     struct rndis_message *msg,
 				     struct vmbus_channel *channel,
@@ -388,7 +389,8 @@ static int rndis_filter_receive_data(struct net_device *ndev,
 	 */
 	data = (void *)((unsigned long)data + data_offset);
 	csum_info = rndis_get_ppi(rndis_pkt, TCPIP_CHKSUM_PKTINFO);
-	return netvsc_recv_callback(ndev, channel,
+
+	return netvsc_recv_callback(ndev, nvdev, channel,
 				    data, rndis_pkt->data_len,
 				    csum_info, vlan);
 }
@@ -420,7 +422,8 @@ int rndis_filter_receive(struct net_device *ndev,
 
 	switch (rndis_msg->ndis_msg_type) {
 	case RNDIS_MSG_PACKET:
-		return rndis_filter_receive_data(ndev, rndis_dev, rndis_msg,
+		return rndis_filter_receive_data(ndev, net_dev,
+						 rndis_dev, rndis_msg,
 						 channel, data, buflen);
 	case RNDIS_MSG_INIT_C:
 	case RNDIS_MSG_QUERY_C: