From: Jiang Lidong <jianglidong3@jd.com>
Date: Wed, 4 Mar 2020 09:49:29 +0800
Subject: veth: ignore peer tx_dropped when counting local rx_dropped
Patch-mainline: v5.6-rc6
Git-commit: e25d5dbcffae62c9a7fa03517dfa4b8e67670e3d
References: bsc#1176447

When local NET_RX backlog is full due to traffic overrun,
peer veth tx_dropped counter increases. At that time, list
local veth stats, rx_dropped has double value of peer
tx_dropped, even bigger than transmit packets by peer.

In NET_RX softirq process, if any packet drop case happens,
it increases dev's rx_dropped counter and returns NET_RX_DROP.

At veth tx side, it records any error returned from peer netif_rx
into local dev tx_dropped counter.

In veth get stats process, it puts local dev rx_dropped and
peer dev tx_dropped into together as local rx_drpped value.
So that it shows double value of real dropped packets number in
this case.

This patch ignores peer tx_dropped when counting local rx_dropped,
since peer tx_dropped is duplicated to local rx_dropped at most cases.

Signed-off-by: Jiang Lidong <jianglidong3@jd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/veth.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -328,7 +328,7 @@ static void veth_get_stats64(struct net_
 	rcu_read_lock();
 	peer = rcu_dereference(priv->peer);
 	if (peer) {
-		tot->rx_dropped += veth_stats_tx(peer, &packets, &bytes);
+		veth_stats_tx(peer, &packets, &bytes);
 		tot->rx_bytes += bytes;
 		tot->rx_packets += packets;