mlx4: TCP/UDP packets have L4 hash

Mellanox driver has the knowledge if rxhash is a L4 hash,
if it receives a non fragmented TCP or UDP frame and
NETIF_F_RXCSUM is enabled on netdev.

ip_summed value is CHECKSUM_UNNECESSARY in this case.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Amir Vadai <amirv@mellanox.com>
Cc: Ido Shamay <idos@mellanox.com>
Acked-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -917,7 +917,9 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 			if (dev->features & NETIF_F_RXHASH)
 				skb_set_hash(gro_skb,
 					     be32_to_cpu(cqe->immed_rss_invalid),
-					     PKT_HASH_TYPE_L3);
+					     (ip_summed == CHECKSUM_UNNECESSARY) ?
+						PKT_HASH_TYPE_L4 :
+						PKT_HASH_TYPE_L3);
 
 			skb_record_rx_queue(gro_skb, cq->ring);
 			skb_mark_napi_id(gro_skb, &cq->napi);
@@ -963,7 +965,9 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 		if (dev->features & NETIF_F_RXHASH)
 			skb_set_hash(skb,
 				     be32_to_cpu(cqe->immed_rss_invalid),
-				     PKT_HASH_TYPE_L3);
+				     (ip_summed == CHECKSUM_UNNECESSARY) ?
+					PKT_HASH_TYPE_L4 :
+					PKT_HASH_TYPE_L3);
 
 		if ((be32_to_cpu(cqe->vlan_my_qpn) &
 		    MLX4_CQE_VLAN_PRESENT_MASK) &&