IB/mlx5: Add support for QP with a given source QPN

Allow user space applications to accelerate send and receive
traffic which is typically handled by IPoIB ULP by creating
a UD QP with a given source QPN of the IPoIB UD QP.

UD QP with a given source QPN should basically be similar to
RAW QP from point of view of its created resources.

However,
- Its TIS should point to the source QPN.
- Modify can be done only on its state as the transport attributes
  are managed by its source QP.

This patch manages below:
- Creating/destroying/modifying UD QP with a given source QPN.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 0316147..7ac9910 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -383,6 +383,7 @@ struct mlx5_ib_qp {
 	struct list_head	cq_recv_list;
 	struct list_head	cq_send_list;
 	u32			rate_limit;
+	u32                     underlay_qpn;
 };
 
 struct mlx5_ib_cq_buf {
@@ -404,6 +405,7 @@ enum mlx5_ib_qp_flags {
 	MLX5_IB_QP_CAP_SCATTER_FCS		= 1 << 7,
 	MLX5_IB_QP_RSS				= 1 << 8,
 	MLX5_IB_QP_CVLAN_STRIPPING		= 1 << 9,
+	MLX5_IB_QP_UNDERLAY			= 1 << 10,
 };
 
 struct mlx5_umr_wr {