[PATCH 5/5] net/mlx5: build port name dynamically

[Dariusz Sosnowski <dsosnowski@nvidia.com>]

When new mlx5 ethdev port was spawned, the port's name was generated
based on specific type of setup the port was probed on.
The types of names however were identical in each case.

In order to prevent future changes, which require adding
specific cases for new specific setups, this patch reworks
the port's name building logic to be dynamic.
This logic will be based on information independent of setup type,
such as:

- number of uplinks (physical ports),
- number of host PFs (host PF representors on BlueField ARM),
- whether port is an uplink,
- whether port is a representor or not.

This patch keeps addition of IB device name in ethdev port name
in case underlying device is a LAG, for name compatibility reasons.

Signed-off-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
---
 drivers/net/mlx5/linux/mlx5_os.c | 122 +++++++++++++++++++++----------
 1 file changed, 84 insertions(+), 38 deletions(-)

diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
index d30106c4c5..324d65cf32 100644
--- a/drivers/net/mlx5/linux/mlx5_os.c
+++ b/drivers/net/mlx5/linux/mlx5_os.c
@@ -1068,6 +1068,84 @@ is_hpf(const struct mlx5_dev_spawn_data *spawn)
 	       spawn->info.name_type == MLX5_PHYS_PORT_NAME_TYPE_PFHPF;
 }
 
+static int
+build_port_name(struct rte_device *dpdk_dev,
+		struct mlx5_dev_spawn_data *spawn,
+		char *name,
+		size_t name_sz)
+{
+	bool is_bond = spawn->pf_bond >= 0;
+	int written = 0;
+	int ret;
+
+	ret = snprintf(name, name_sz, "%s", dpdk_dev->name);
+	if (ret < 0)
+		return ret;
+	written += ret;
+	if (written >= (int)name_sz)
+		return written;
+
+	/*
+	 * Whenever bond device is detected, include IB device name.
+	 * This is kept to keep port naming backward compatible.
+	 */
+	if (is_bond) {
+		ret = snprintf(name + written, name_sz - written, "_%s", spawn->phys_dev_name);
+		if (ret < 0)
+			return ret;
+		written += ret;
+		if (written >= (int)name_sz)
+			return written;
+	}
+
+	if (spawn->info.name_type == MLX5_PHYS_PORT_NAME_TYPE_UPLINK) {
+		/* Add port to name if and only if there is more than one uplink. */
+		if (spawn->nb_uplinks <= 1)
+			goto end;
+
+		ret = snprintf(name + written, name_sz - written, "_p%u", spawn->info.port_name);
+		if (ret < 0)
+			return ret;
+		written += ret;
+		if (written >= (int)name_sz)
+			return written;
+	} else if (spawn->info.representor) {
+		/*
+		 * If port is a representor, then switchdev has been enabled.
+		 * In that case add controller, PF and VF/SF indexes to port name
+		 * if at least one of these conditions are met:
+		 * 1. Device is a bond (VF-LAG).
+		 * 2. There are multiple uplinks (MPESW).
+		 * 3. There are multiple host PFs (BlueField socket direct).
+		 *
+		 * If none of these conditions apply, then it is assumed that
+		 * this device manages a single non-shared E-Switch with single controller,
+		 * where there is only one uplink/PF and one host PF (on BlueField).
+		 */
+		if (!is_standard_eswitch(spawn))
+			ret = snprintf(name + written, name_sz - written,
+				       "_representor_c%dpf%d%s%u",
+				       spawn->info.ctrl_num,
+				       spawn->info.pf_num,
+				       spawn->info.name_type ==
+				       MLX5_PHYS_PORT_NAME_TYPE_PFSF ? "sf" : "vf",
+				       spawn->info.port_name);
+		else
+			ret = snprintf(name + written, name_sz - written, "_representor_%s%u",
+				       spawn->info.name_type ==
+				       MLX5_PHYS_PORT_NAME_TYPE_PFSF ? "sf" : "vf",
+				       spawn->info.port_name);
+		if (ret < 0)
+			return ret;
+		written += ret;
+		if (written >= (int)name_sz)
+			return written;
+	}
+
+end:
+	return written;
+}
+
 static bool
 representor_match_uplink(const struct mlx5_dev_spawn_data *spawn,
 			 uint16_t port_name,
@@ -1247,44 +1325,12 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev,
 	    !mlx5_representor_match(spawn, eth_da))
 		return NULL;
 	/* Build device name. */
-	if (spawn->pf_bond >= 0) {
-		/* Bonding device. */
-		if (!switch_info->representor) {
-			err = snprintf(name, sizeof(name), "%s_%s",
-				       dpdk_dev->name, spawn->phys_dev_name);
-		} else {
-			err = snprintf(name, sizeof(name), "%s_%s_representor_c%dpf%d%s%u",
-				dpdk_dev->name, spawn->phys_dev_name,
-				switch_info->ctrl_num,
-				switch_info->pf_num,
-				switch_info->name_type ==
-				MLX5_PHYS_PORT_NAME_TYPE_PFSF ? "sf" : "vf",
-				switch_info->port_name);
-		}
-	} else if (mlx5_is_probed_port_on_mpesw_device(spawn)) {
-		/* MPESW device. */
-		if (switch_info->name_type == MLX5_PHYS_PORT_NAME_TYPE_UPLINK) {
-			err = snprintf(name, sizeof(name), "%s_p%d",
-				       dpdk_dev->name, spawn->mpesw_port);
-		} else {
-			err = snprintf(name, sizeof(name), "%s_representor_c%dpf%d%s%u",
-				dpdk_dev->name,
-				switch_info->ctrl_num,
-				switch_info->pf_num,
-				switch_info->name_type ==
-				MLX5_PHYS_PORT_NAME_TYPE_PFSF ? "sf" : "vf",
-				switch_info->port_name);
-		}
-	} else {
-		/* Single device. */
-		if (!switch_info->representor)
-			strlcpy(name, dpdk_dev->name, sizeof(name));
-		else
-			err = snprintf(name, sizeof(name), "%s_representor_%s%u",
-				 dpdk_dev->name,
-				 switch_info->name_type ==
-				 MLX5_PHYS_PORT_NAME_TYPE_PFSF ? "sf" : "vf",
-				 switch_info->port_name);
+	err = build_port_name(dpdk_dev, spawn, name, sizeof(name));
+	if (err < 0) {
+		DRV_LOG(ERR, "Failed to build port name for IB device %s/%u",
+			spawn->phys_dev_name, spawn->phys_port);
+		rte_errno = EINVAL;
+		return NULL;
 	}
 	if (err >= (int)sizeof(name))
 		DRV_LOG(WARNING, "device name overflow %s", name);
-- 
2.47.3