IB/mlx5: Handle page faults

This patch implement a page fault handler (leaving the pages pinned as
of time being).  The page fault handler handles initiator and responder
page faults for UD/RC transports, for send/receive operations, as well
as RDMA read/write initiator support.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

include/linux/mlx5/qp.h

@@ -193,7 +193,12 @@ struct mlx5_wqe_ctrl_seg {
 };
 
 #define MLX5_WQE_CTRL_DS_MASK 0x3f
+#define MLX5_WQE_CTRL_QPN_MASK 0xffffff00
+#define MLX5_WQE_CTRL_QPN_SHIFT 8
 #define MLX5_WQE_DS_UNITS 16
+#define MLX5_WQE_CTRL_OPCODE_MASK 0xff
+#define MLX5_WQE_CTRL_WQE_INDEX_MASK 0x00ffff00
+#define MLX5_WQE_CTRL_WQE_INDEX_SHIFT 8
 
 struct mlx5_wqe_xrc_seg {
 	__be32			xrc_srqn;
@@ -298,6 +303,8 @@ struct mlx5_wqe_signature_seg {
 	u8	rsvd1[11];
 };
 
+#define MLX5_WQE_INLINE_SEG_BYTE_COUNT_MASK 0x3ff
+
 struct mlx5_wqe_inline_seg {
 	__be32	byte_count;
 };