net/mlx5: cache associated network device index

[ upstream commit fa2e14d ]

The associated device index is retrieved via Netlink request to
underlying Infiniband device driver. This network device index
is permanent throughout the lifetime of device. We do not
spawn the rte_eth_dev ports without associated network device, and
if network device is being unbound we get the remove notification
message and rte_eth_dev port is also detached. So, we may store
the ifindex in mlx5_device_spawn() routine at rte_eth_dev port
creation and initialization time and use the cached value further
instead of doing actual Netlink request.

Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Yongseok Koh <yskoh@mellanox.com>

drivers/net/mlx5/mlx5.c

@@ -734,7 +734,8 @@ static struct rte_eth_dev *
 mlx5_dev_spawn(struct rte_device *dpdk_dev,
 	       struct ibv_device *ibv_dev,
 	       struct mlx5_dev_config config,
-	       const struct mlx5_switch_info *switch_info)
+	       const struct mlx5_switch_info *switch_info,
+	       unsigned int ifindex)
 {
 	struct ibv_context *ctx;
 	struct ibv_device_attr_ex attr;
@@ -1132,6 +1133,12 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev,
 		eth_dev->data->dev_flags |= RTE_ETH_DEV_REPRESENTOR;
 		eth_dev->data->representor_id = priv->representor_id;
 	}
+	/*
+	 * Store associated network device interface index. This index
+	 * is permanent throughout the lifetime of device. So, we may store
+	 * the ifindex here and use the cached value further.
+	 */
+	priv->if_index = ifindex;
 	eth_dev->data->dev_private = priv;
 	priv->dev_data = eth_dev->data;
 	eth_dev->data->mac_addrs = priv->mac;
@@ -1492,7 +1499,7 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
 
 		list[i].eth_dev = mlx5_dev_spawn(&pci_dev->device,
 						 list[i].ibv_dev, dev_config,
-						 &list[i].info);
+						 &list[i].info, list[i].ifindex);
 		if (!list[i].eth_dev) {
 			if (rte_errno != EBUSY && rte_errno != EEXIST)
 				break;

drivers/net/mlx5/mlx5.h

@@ -197,6 +197,7 @@ struct mlx5_priv {
 	unsigned int representor:1; /* Device is a port representor. */
 	uint16_t domain_id; /* Switch domain identifier. */
 	int32_t representor_id; /* Port representor identifier. */
+	unsigned int if_index; /* Associated kernel network device index. */
 	/* RX/TX queues. */
 	unsigned int rxqs_n; /* RX queues array size. */
 	unsigned int txqs_n; /* TX queues array size. */

drivers/net/mlx5/mlx5_ethdev.c

@@ -220,10 +220,10 @@ int
 mlx5_get_ifname(const struct rte_eth_dev *dev, char (*ifname)[IF_NAMESIZE])
 {
 	struct mlx5_priv *priv = dev->data->dev_private;
-	unsigned int ifindex =
-		priv->nl_socket_rdma >= 0 ?
-		mlx5_nl_ifindex(priv->nl_socket_rdma, priv->ibdev_name) : 0;
+	unsigned int ifindex;
 
+	assert(priv);
+	ifindex = mlx5_ifindex(dev);
 	if (!ifindex) {
 		if (!priv->representor)
 			return mlx5_get_master_ifname(dev, ifname);
@@ -248,14 +248,14 @@ mlx5_get_ifname(const struct rte_eth_dev *dev, char (*ifname)[IF_NAMESIZE])
 unsigned int
 mlx5_ifindex(const struct rte_eth_dev *dev)
 {
-	char ifname[IF_NAMESIZE];
+	struct mlx5_priv *priv = dev->data->dev_private;
 	unsigned int ifindex;
 
-	if (mlx5_get_ifname(dev, &ifname))
-		return 0;
-	ifindex = if_nametoindex(ifname);
+	assert(priv);
+	assert(priv->if_index);
+	ifindex = priv->if_index;
 	if (!ifindex)
-		rte_errno = errno;
+		rte_errno = ENXIO;
 	return ifindex;
 }
 
@@ -502,7 +502,6 @@ mlx5_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)
 	struct mlx5_priv *priv = dev->data->dev_private;
 	struct mlx5_dev_config *config = &priv->config;
 	unsigned int max;
-	char ifname[IF_NAMESIZE];
 
 	/* FIXME: we should ask the device for these values. */
 	info->min_rx_bufsize = 32;
@@ -523,8 +522,7 @@ mlx5_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)
 	info->rx_offload_capa = (mlx5_get_rx_port_offloads() |
 				 info->rx_queue_offload_capa);
 	info->tx_offload_capa = mlx5_get_tx_port_offloads(dev);
-	if (mlx5_get_ifname(dev, &ifname) == 0)
-		info->if_index = if_nametoindex(ifname);
+	info->if_index = mlx5_ifindex(dev);
 	info->reta_size = priv->reta_idx_n ?
 		priv->reta_idx_n : config->ind_table_max_size;
 	info->hash_key_size = MLX5_RSS_HASH_KEY_LEN;