macvlan: don't broadcast PAUSE frames to macvlan devices

PAUSE frames are only relevant for the real device, broadcasting them
to all macvlan devices can cause a significant load increase.

Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 4239450..590039c 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -70,6 +70,9 @@
 	struct sk_buff *nskb;
 	unsigned int i;
 
+	if (skb->protocol == htons(ETH_P_PAUSE))
+		return;
+
 	for (i = 0; i < MACVLAN_HASH_SIZE; i++) {
 		hlist_for_each_entry_rcu(vlan, n, &port->vlan_hash[i], hlist) {
 			dev = vlan->dev;