net/mlx4: Add RSS support for fragmented IP datagrams

Enable RSS support for fragmented IP packets, when device supports it.
Until now, fragmented IP packets were directed only to the default_qpn.
Since IP fragments (datagram) have no upper protocols (L3 IP packets),
hash is performed on 3-tuple - dst MAC, source IP and dest IP. The HW
makes sure that this holds for the 1st fragment too, so all fragments
go to the same QP.

Signed-off-by: Ido Shamay <idos@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 43aa767..ee0a670 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -885,6 +885,8 @@
 	mlx4_warn(dev, "Timestamping is not supported in slave mode\n");
 
 	slave_adjust_steering_mode(dev, &dev_cap, &hca_param);
+	mlx4_dbg(dev, "RSS support for IP fragments is %s\n",
+		 hca_param.rss_ip_frags ? "on" : "off");
 
 	if (func_cap.extra_flags & MLX4_QUERY_FUNC_FLAGS_BF_RES_QP &&
 	    dev->caps.bf_reg_size)