[PATCH rdma-next v1] RDMA/mlx5: Support TX port affinity for VF drivers in LAG mode

[Leon Romanovsky <leon@kernel.org>]

From: Mark Zhang <markz@mellanox.com>

The mlx5 VF driver doesn't set QP tx port affinity because it doesn't
know if the lag is active or not, since the "lag_active" works only for
PF interfaces. In this case for VF interfaces only one lag is used
which brings performance issue.

Add a lag_tx_port_affinity CAP bit; When it is enabled and
"num_lag_ports > 1", then driver always set QP tx affinity, regardless
of lag state.

Signed-off-by: Mark Zhang <markz@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
Changelog
v1:
 * Fixed wrong check of num_lag_ports.
v0: https://lore.kernel.org/linux-rdma/20200526143457.218840-1-leon@kernel.org
---
 drivers/infiniband/hw/mlx5/main.c    | 2 +-
 drivers/infiniband/hw/mlx5/mlx5_ib.h | 7 +++++++
 drivers/infiniband/hw/mlx5/qp.c      | 3 ++-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 570c519ca530..4719da201382 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1984,7 +1984,7 @@ static int mlx5_ib_alloc_ucontext(struct ib_ucontext *uctx,
 	context->lib_caps = req.lib_caps;
 	print_lib_caps(dev, context->lib_caps);

-	if (dev->lag_active) {
+	if (mlx5_ib_lag_should_assign_affinity(dev)) {
 		u8 port = mlx5_core_native_port_num(dev->mdev) - 1;

 		atomic_set(&context->tx_port_affinity,
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index b486139b08ce..236c5c4a3637 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1553,4 +1553,11 @@ static inline bool mlx5_ib_can_use_umr(struct mlx5_ib_dev *dev,

 int mlx5_ib_enable_driver(struct ib_device *dev);
 int mlx5_ib_test_wc(struct mlx5_ib_dev *dev);
+
+static inline bool mlx5_ib_lag_should_assign_affinity(struct mlx5_ib_dev *dev)
+{
+	return dev->lag_active ||
+		(MLX5_CAP_GEN(dev->mdev, num_lag_ports) > 1 &&
+		 MLX5_CAP_GEN(dev->mdev, lag_tx_port_affinity));
+}
 #endif /* MLX5_IB_H */
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 1988a0375696..9364a7a76ac2 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -3653,7 +3653,8 @@ static unsigned int get_tx_affinity(struct ib_qp *qp,
 	struct mlx5_ib_qp_base *qp_base;
 	unsigned int tx_affinity;

-	if (!(dev->lag_active && qp_supports_affinity(qp)))
+	if (!(mlx5_ib_lag_should_assign_affinity(dev) &&
+	      qp_supports_affinity(qp)))
 		return 0;

 	if (mqp->flags & MLX5_IB_QP_CREATE_SQPN_QP1)
--
2.26.2