net/mlx5: fix MPRQ stride size check

[ upstream commit fdee0f1b30ae8dfc431465878aae5295372cca6f ]

We should only check that MPRQ stride size is bigger than the mbuf size
in case no devarg configuration has been provided. Headroom check was
indtroduced recently and removed this condition inadvertently.
Restore this condition and only check if mprq_log_stride_size is not set.

Fixes: e6479f009fbd ("net/mlx5: fix MPRQ stride size for headroom")

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

drivers/net/mlx5/linux/mlx5_os.c

@@ -1202,7 +1202,7 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev,
 	config->mprq.log_min_stride_wqe_size =
 			MLX5_MPRQ_LOG_MIN_STRIDE_WQE_SIZE;
 	config->mprq.log_stride_num = MLX5_MPRQ_DEFAULT_LOG_STRIDE_NUM;
-	config->mprq.log_stride_size = MLX5_MPRQ_DEFAULT_LOG_STRIDE_SIZE;
+	config->mprq.log_stride_size = MLX5_ARG_UNSET;
 	if (config->devx) {
 		config->mprq.log_min_stride_wqe_size =
 				config->hca_attr.log_min_stride_wqe_sz;

drivers/net/mlx5/mlx5_rxq.c

@@ -1447,18 +1447,19 @@ mlx5_mprq_prepare(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
 		*actual_log_stride_num = config->mprq.log_stride_num;
 	}
 	/* Checks if chosen size of stride is in supported range. */
-	if (config->mprq.log_stride_size > log_max_stride_size ||
-	    config->mprq.log_stride_size < log_min_stride_size) {
-		*actual_log_stride_size = log_def_stride_size;
-		DRV_LOG(WARNING,
-			"Port %u Rx queue %u size of a stride for Multi-Packet RQ is out of range, setting default value (%u)",
-			dev->data->port_id, idx,
-			RTE_BIT32(log_def_stride_size));
+	if (config->mprq.log_stride_size != (uint32_t)MLX5_ARG_UNSET) {
+		if (config->mprq.log_stride_size > log_max_stride_size ||
+			config->mprq.log_stride_size < log_min_stride_size) {
+			*actual_log_stride_size = log_def_stride_size;
+			DRV_LOG(WARNING,
+				"Port %u Rx queue %u size of a stride for Multi-Packet RQ is out of range, setting default value (%u)",
+				dev->data->port_id, idx,
+				RTE_BIT32(log_def_stride_size));
+		} else {
+			*actual_log_stride_size = config->mprq.log_stride_size;
+		}
 	} else {
-		*actual_log_stride_size = config->mprq.log_stride_size;
-	}
-	/* Make the stride fit the mbuf size by default. */
-	if (*actual_log_stride_size == MLX5_MPRQ_DEFAULT_LOG_STRIDE_SIZE) {
+		/* Make the stride fit the mbuf size by default. */
 		if (min_mbuf_size <= RTE_BIT32(log_max_stride_size)) {
 			DRV_LOG(WARNING,
 				"Port %u Rx queue %u size of a stride for Multi-Packet RQ is adjusted to match the mbuf size (%u)",
@@ -1517,6 +1518,8 @@ mlx5_mprq_prepare(struct rte_eth_dev *dev, uint16_t idx, uint16_t desc,
 			" min_stride_sz = %u, max_stride_sz = %u).\n"
 			"Rx segment is %senabled. External mempool is %sused.",
 			dev->data->port_id, min_mbuf_size, desc, priv->rxqs_n,
+			config->mprq.log_stride_size == (uint32_t)MLX5_ARG_UNSET ?
+			RTE_BIT32(MLX5_MPRQ_DEFAULT_LOG_STRIDE_SIZE) :
 			RTE_BIT32(config->mprq.log_stride_size),
 			RTE_BIT32(config->mprq.log_stride_num),
 			config->mprq.min_rxqs_num,