net/mlx5e: Derive Striding RQ size from MTU

In Striding RQ, each WQE serves multiple packets
(hence called Multi-Packet WQE, MPWQE).
The size of a MPWQE is constant (currently 256KB).

Upon a ringparam set operation, we calculate the number of
MPWQEs per RQ. For this, first it is needed to determine the
number of packets that can reside within a single MPWQE.
In this patch we use the actual MTU size instead of ETH_DATA_LEN
for this calculation.

This implies that a change in MTU might require a change
in Striding RQ ring size.

In addition, this obsoletes some WQEs-to-packets translation
functions and helps delete ~60 LOC.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

1 files changed, 7 insertions, 72 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index c57c929d7973..a87d46bc2299 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -220,60 +220,12 @@ static void mlx5e_get_ethtool_stats(struct net_device *dev,
 	mlx5e_ethtool_get_ethtool_stats(priv, stats, data);
 }
 
-static u32 mlx5e_rx_wqes_to_packets(struct mlx5e_priv *priv, int rq_wq_type,
-				    int num_wqe)
-{
-	int packets_per_wqe;
-	int stride_size;
-	int num_strides;
-	int wqe_size;
-
-	if (rq_wq_type != MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ)
-		return num_wqe;
-
-	stride_size = 1 << mlx5e_mpwqe_get_log_stride_size(priv->mdev, &priv->channels.params);
-	num_strides = 1 << mlx5e_mpwqe_get_log_num_strides(priv->mdev, &priv->channels.params);
-	wqe_size = stride_size * num_strides;
-
-	packets_per_wqe = wqe_size /
-			  ALIGN(ETH_DATA_LEN, stride_size);
-	return (1 << (order_base_2(num_wqe * packets_per_wqe) - 1));
-}
-
-static u32 mlx5e_packets_to_rx_wqes(struct mlx5e_priv *priv, int rq_wq_type,
-				    int num_packets)
-{
-	int packets_per_wqe;
-	int stride_size;
-	int num_strides;
-	int wqe_size;
-	int num_wqes;
-
-	if (rq_wq_type != MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ)
-		return num_packets;
-
-	stride_size = 1 << mlx5e_mpwqe_get_log_stride_size(priv->mdev, &priv->channels.params);
-	num_strides = 1 << mlx5e_mpwqe_get_log_num_strides(priv->mdev, &priv->channels.params);
-	wqe_size = stride_size * num_strides;
-
-	num_packets = (1 << order_base_2(num_packets));
-
-	packets_per_wqe = wqe_size /
-			  ALIGN(ETH_DATA_LEN, stride_size);
-	num_wqes = DIV_ROUND_UP(num_packets, packets_per_wqe);
-	return 1 << (order_base_2(num_wqes));
-}
-
 void mlx5e_ethtool_get_ringparam(struct mlx5e_priv *priv,
 				 struct ethtool_ringparam *param)
 {
-	int rq_wq_type = priv->channels.params.rq_wq_type;
-
-	param->rx_max_pending = mlx5e_rx_wqes_to_packets(priv, rq_wq_type,
-							 1 << mlx5_max_log_rq_size(rq_wq_type));
+	param->rx_max_pending = 1 << MLX5E_PARAMS_MAXIMUM_LOG_RQ_SIZE;
 	param->tx_max_pending = 1 << MLX5E_PARAMS_MAXIMUM_LOG_SQ_SIZE;
-	param->rx_pending = mlx5e_rx_wqes_to_packets(priv, rq_wq_type,
-						     1 << priv->channels.params.log_rq_size);
+	param->rx_pending     = 1 << priv->channels.params.log_rq_mtu_frames;
 	param->tx_pending     = 1 << priv->channels.params.log_sq_size;
 }
 
@@ -288,13 +240,9 @@ static void mlx5e_get_ringparam(struct net_device *dev,
 int mlx5e_ethtool_set_ringparam(struct mlx5e_priv *priv,
 				struct ethtool_ringparam *param)
 {
-	int rq_wq_type = priv->channels.params.rq_wq_type;
 	struct mlx5e_channels new_channels = {};
-	u32 rx_pending_wqes;
-	u32 min_rq_size;
 	u8 log_rq_size;
 	u8 log_sq_size;
-	u32 num_mtts;
 	int err = 0;
 
 	if (param->rx_jumbo_pending) {
@@ -308,23 +256,10 @@ int mlx5e_ethtool_set_ringparam(struct mlx5e_priv *priv,
 		return -EINVAL;
 	}
 
-	min_rq_size = mlx5e_rx_wqes_to_packets(priv, rq_wq_type,
-					       1 << mlx5_min_log_rq_size(rq_wq_type));
-	rx_pending_wqes = mlx5e_packets_to_rx_wqes(priv, rq_wq_type,
-						   param->rx_pending);
-
-	if (param->rx_pending < min_rq_size) {
+	if (param->rx_pending < (1 << MLX5E_PARAMS_MINIMUM_LOG_RQ_SIZE)) {
 		netdev_info(priv->netdev, "%s: rx_pending (%d) < min (%d)\n",
 			    __func__, param->rx_pending,
-			    min_rq_size);
-		return -EINVAL;
-	}
-
-	num_mtts = MLX5E_REQUIRED_MTTS(rx_pending_wqes);
-	if (priv->channels.params.rq_wq_type == MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ &&
-	    !MLX5E_VALID_NUM_MTTS(num_mtts)) {
-		netdev_info(priv->netdev, "%s: rx_pending (%d) request can't be satisfied, try to reduce.\n",
-			    __func__, param->rx_pending);
+			    1 << MLX5E_PARAMS_MINIMUM_LOG_RQ_SIZE);
 		return -EINVAL;
 	}
 
@@ -335,17 +270,17 @@ int mlx5e_ethtool_set_ringparam(struct mlx5e_priv *priv,
 		return -EINVAL;
 	}
 
-	log_rq_size = order_base_2(rx_pending_wqes);
+	log_rq_size = order_base_2(param->rx_pending);
 	log_sq_size = order_base_2(param->tx_pending);
 
-	if (log_rq_size == priv->channels.params.log_rq_size &&
+	if (log_rq_size == priv->channels.params.log_rq_mtu_frames &&
 	    log_sq_size == priv->channels.params.log_sq_size)
 		return 0;
 
 	mutex_lock(&priv->state_lock);
 
 	new_channels.params = priv->channels.params;
-	new_channels.params.log_rq_size = log_rq_size;
+	new_channels.params.log_rq_mtu_frames = log_rq_size;
 	new_channels.params.log_sq_size = log_sq_size;
 
 	if (!test_bit(MLX5E_STATE_OPENED, &priv->state)) {