net: Fix napi_gro_frags vs netpoll path

The netpoll_rx_on() check in __napi_gro_receive() skips part of the
"common" GRO_NORMAL path, especially "pull:" in dev_gro_receive(),
where at least eth header should be copied for entirely paged skbs.
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -3072,7 +3072,7 @@ enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
 	int mac_len;
 	enum gro_result ret;
 
-	if (!(skb->dev->features & NETIF_F_GRO))
+	if (!(skb->dev->features & NETIF_F_GRO) || netpoll_rx_on(skb))
 		goto normal;
 
 	if (skb_is_gso(skb) || skb_has_frags(skb))
@@ -3159,9 +3159,6 @@ __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
 {
 	struct sk_buff *p;
 
-	if (netpoll_rx_on(skb))
-		return GRO_NORMAL;
-
 	for (p = napi->gro_list; p; p = p->next) {
 		NAPI_GRO_CB(p)->same_flow =
 			(p->dev == skb->dev) &&