[dpdk-dev] [PATCH v3] net/mlx5: optimize Rx hash fields conversion

[Dekel Peled <dekelp@mellanox.com>]

Previous fix added translation of Rx hash fields to PRM format.

This patch optimizes the fix, to perform value translation only
if value is not zero.
In case value is zero, there is no need to translate it.

Fixes: 51035775c3c7 ("net/mlx5: fix setting of Rx hash fields")
Cc: stable@dpdk.org

Signed-off-by: Dekel Peled <dekelp@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

---
v2: Modify title for clarity, change 'fix' to 'optimize'.
    Remove the 'Fixes' label. 
v3: Add back the 'Fixes' label.
---

---
 drivers/net/mlx5/mlx5_rxq.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
index ca25e32..c936a7f 100644
--- a/drivers/net/mlx5/mlx5_rxq.c
+++ b/drivers/net/mlx5/mlx5_rxq.c
@@ -2460,7 +2460,6 @@ struct mlx5_hrxq *
 		}
 	} else { /* ind_tbl->type == MLX5_IND_TBL_TYPE_DEVX */
 		struct mlx5_devx_tir_attr tir_attr;
-		struct mlx5_rx_hash_field_select *rx_hash_field_select;
 		uint32_t i;
 		uint32_t lro = 1;
 
@@ -2474,23 +2473,27 @@ struct mlx5_hrxq *
 		memset(&tir_attr, 0, sizeof(tir_attr));
 		tir_attr.disp_type = MLX5_TIRC_DISP_TYPE_INDIRECT;
 		tir_attr.rx_hash_fn = MLX5_RX_HASH_FN_TOEPLITZ;
-#ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
 		tir_attr.tunneled_offload_en = !!tunnel;
-		/* Translate hash_fields bitmap to PRM format. */
-		rx_hash_field_select = hash_fields & IBV_RX_HASH_INNER ?
-				       &tir_attr.rx_hash_field_selector_inner :
-				       &tir_attr.rx_hash_field_selector_outer;
+		/* If needed, translate hash_fields bitmap to PRM format. */
+		if (hash_fields) {
+#ifdef HAVE_IBV_DEVICE_TUNNEL_SUPPORT
+			struct mlx5_rx_hash_field_select *rx_hash_field_select =
+					hash_fields & IBV_RX_HASH_INNER ?
+					&tir_attr.rx_hash_field_selector_inner :
+					&tir_attr.rx_hash_field_selector_outer;
 #else
-		rx_hash_field_select = &tir_attr.rx_hash_field_selector_outer;
+			struct mlx5_rx_hash_field_select *rx_hash_field_select =
+					&tir_attr.rx_hash_field_selector_outer;
 #endif
-		/* 1 bit: 0: IPv4, 1: IPv6. */
-		rx_hash_field_select->l3_prot_type =
-			!!(hash_fields & MLX5_IPV6_IBV_RX_HASH);
-		/* 1 bit: 0: TCP, 1: UDP. */
-		rx_hash_field_select->l4_prot_type =
-			!!(hash_fields & MLX5_UDP_IBV_RX_HASH);
-		/* Bitmask which sets which fields to use in RX Hash. */
-		rx_hash_field_select->selected_fields =
+
+			/* 1 bit: 0: IPv4, 1: IPv6. */
+			rx_hash_field_select->l3_prot_type =
+				!!(hash_fields & MLX5_IPV6_IBV_RX_HASH);
+			/* 1 bit: 0: TCP, 1: UDP. */
+			rx_hash_field_select->l4_prot_type =
+				!!(hash_fields & MLX5_UDP_IBV_RX_HASH);
+			/* Bitmask which sets which fields to use in RX Hash. */
+			rx_hash_field_select->selected_fields =
 			((!!(hash_fields & MLX5_L3_SRC_IBV_RX_HASH)) <<
 			 MLX5_RX_HASH_FIELD_SELECT_SELECTED_FIELDS_SRC_IP) |
 			(!!(hash_fields & MLX5_L3_DST_IBV_RX_HASH)) <<
@@ -2499,6 +2502,7 @@ struct mlx5_hrxq *
 			 MLX5_RX_HASH_FIELD_SELECT_SELECTED_FIELDS_L4_SPORT |
 			(!!(hash_fields & MLX5_L4_DST_IBV_RX_HASH)) <<
 			 MLX5_RX_HASH_FIELD_SELECT_SELECTED_FIELDS_L4_DPORT;
+		}
 		if (rxq_ctrl->obj->type == MLX5_RXQ_OBJ_TYPE_DEVX_HAIRPIN)
 			tir_attr.transport_domain = priv->sh->td->id;
 		else
-- 
1.8.3.1