Merge branch 'mlx5-packet-credit-fc' into rdma.git

Danit Goldberg says:

Packet based credit mode

Packet based credit mode is an alternative end-to-end credit mode for QPs
set during their creation. Credits are transported from the responder to
the requester to optimize the use of its receive resources.  In
packet-based credit mode, credits are issued on a per packet basis.

The advantage of this feature comes while sending large RDMA messages
through switches that are short in memory.

The first commit exposes QP creation flag and the HCA capability. The
second commit adds support for a new DV QP creation flag. The last commit
report packet based credit mode capability via the MLX5DV device
capabilities.

* branch 'mlx5-packet-credit-fc':
  IB/mlx5: Report packet based credit mode device capability
  IB/mlx5: Add packet based credit mode support
  net/mlx5: Expose packet based credit mode

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

3 files changed, 17 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 2b09e6896e5a..1b2e5465b882 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1018,6 +1018,9 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
 
 		if (MLX5_CAP_GEN(mdev, cqe_128_always))
 			resp.flags |= MLX5_IB_QUERY_DEV_RESP_FLAGS_CQE_128B_PAD;
+		if (MLX5_CAP_GEN(mdev, qp_packet_based))
+			resp.flags |=
+				MLX5_IB_QUERY_DEV_RESP_PACKET_BASED_CREDIT_MODE;
 	}
 
 	if (field_avail(typeof(resp), sw_parsing_caps,
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 24cb2f793210..7145f512f948 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -462,6 +462,7 @@ enum mlx5_ib_qp_flags {
 	MLX5_IB_QP_UNDERLAY			= 1 << 10,
 	MLX5_IB_QP_PCI_WRITE_END_PADDING	= 1 << 11,
 	MLX5_IB_QP_TUNNEL_OFFLOAD		= 1 << 12,
+	MLX5_IB_QP_PACKET_BASED_CREDIT		= 1 << 13,
 };
 
 struct mlx5_umr_wr {
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 48f2e1fbeff8..7789367114f7 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -1917,7 +1917,8 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 					      MLX5_QP_FLAG_BFREG_INDEX |
 					      MLX5_QP_FLAG_TYPE_DCT |
 					      MLX5_QP_FLAG_TYPE_DCI |
-					      MLX5_QP_FLAG_ALLOW_SCATTER_CQE))
+					      MLX5_QP_FLAG_ALLOW_SCATTER_CQE |
+					      MLX5_QP_FLAG_PACKET_BASED_CREDIT_MODE))
 			return -EINVAL;
 
 		err = get_qp_user_index(to_mucontext(pd->uobject->context),
@@ -1953,6 +1954,15 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 			qp->flags_en |= MLX5_QP_FLAG_TIR_ALLOW_SELF_LB_MC;
 		}
 
+		if (ucmd.flags & MLX5_QP_FLAG_PACKET_BASED_CREDIT_MODE) {
+			if (init_attr->qp_type != IB_QPT_RC ||
+				!MLX5_CAP_GEN(dev->mdev, qp_packet_based)) {
+				mlx5_ib_dbg(dev, "packet based credit mode isn't supported\n");
+				return -EOPNOTSUPP;
+			}
+			qp->flags |= MLX5_IB_QP_PACKET_BASED_CREDIT;
+		}
+
 		if (init_attr->create_flags & IB_QP_CREATE_SOURCE_QPN) {
 			if (init_attr->qp_type != IB_QPT_UD ||
 			    (MLX5_CAP_GEN(dev->mdev, port_type) !=
@@ -2049,7 +2059,8 @@ static int create_qp_common(struct mlx5_ib_dev *dev, struct ib_pd *pd,
 		MLX5_SET(qpc, qpc, cd_slave_send, 1);
 	if (qp->flags & MLX5_IB_QP_MANAGED_RECV)
 		MLX5_SET(qpc, qpc, cd_slave_receive, 1);
-
+	if (qp->flags & MLX5_IB_QP_PACKET_BASED_CREDIT)
+		MLX5_SET(qpc, qpc, req_e2e_credit_mode, 1);
 	if (qp->scat_cqe && is_connected(init_attr->qp_type)) {
 		configure_responder_scat_cqe(init_attr, qpc);
 		configure_requester_scat_cqe(dev, init_attr,