IB/mlx4: Use correct SL on AH query under RoCE

The mlx4 IB driver implementation for ib_query_ah used a wrong offset
(28 instead of 29) when link type is Ethernet. Fixed to use the correct one.

Fixes: fa417f7b ('IB/mlx4: Add support for IBoE')
Signed-off-by: NShani Michaeli <shanim@mellanox.com>
Signed-off-by: NNoa Osherovich <noaos@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx4/ah.c

@@ -148,9 +148,13 @@ int mlx4_ib_query_ah(struct ib_ah *ibah, struct ib_ah_attr *ah_attr)
 	enum rdma_link_layer ll;
 
 	memset(ah_attr, 0, sizeof *ah_attr);
-	ah_attr->sl = be32_to_cpu(ah->av.ib.sl_tclass_flowlabel) >> 28;
 	ah_attr->port_num = be32_to_cpu(ah->av.ib.port_pd) >> 24;
 	ll = rdma_port_get_link_layer(ibah->device, ah_attr->port_num);
+	if (ll == IB_LINK_LAYER_ETHERNET)
+		ah_attr->sl = be32_to_cpu(ah->av.eth.sl_tclass_flowlabel) >> 29;
+	else
+		ah_attr->sl = be32_to_cpu(ah->av.ib.sl_tclass_flowlabel) >> 28;
+
 	ah_attr->dlid = ll == IB_LINK_LAYER_INFINIBAND ? be16_to_cpu(ah->av.ib.dlid) : 0;
 	if (ah->av.ib.stat_rate)
 		ah_attr->static_rate = ah->av.ib.stat_rate - MLX4_STAT_RATE_OFFSET;