mlxsw: spectrum: Do not try to create non-existing ports during unsplit

On some systems, when we unsplit a port we need to re-create two ports
instead. On other systems, only one needs to be re-created.

Do not try to create a port if during driver initialization it was
assigned a negative module number, which is invalid.

This avoids the following error during unsplit:
[  941.012478] mlxsw_spectrum 0000:01:00.0: Port 43: Failed to map module

The error is harmless and caused by the fact that a local port is
already mapped to module 0.

Fixes: be94535f9531 ("mlxsw: spectrum: Make split flow match firmware requirements")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -3142,13 +3142,17 @@ static int mlxsw_sp_ports_create(struct mlxsw_sp *mlxsw_sp)
 	if (!mlxsw_sp->ports)
 		return -ENOMEM;
 
-	mlxsw_sp->port_to_module = kcalloc(max_ports, sizeof(u8), GFP_KERNEL);
+	mlxsw_sp->port_to_module = kmalloc_array(max_ports, sizeof(int),
+						 GFP_KERNEL);
 	if (!mlxsw_sp->port_to_module) {
 		err = -ENOMEM;
 		goto err_port_to_module_alloc;
 	}
 
 	for (i = 1; i < max_ports; i++) {
+		/* Mark as invalid */
+		mlxsw_sp->port_to_module[i] = -1;
+
 		err = mlxsw_sp_port_module_info_get(mlxsw_sp, i, &module,
 						    &width, &lane);
 		if (err)
@@ -3216,6 +3220,8 @@ static void mlxsw_sp_port_unsplit_create(struct mlxsw_sp *mlxsw_sp,
 
 	for (i = 0; i < count; i++) {
 		local_port = base_port + i * 2;
+		if (mlxsw_sp->port_to_module[local_port] < 0)
+			continue;
 		module = mlxsw_sp->port_to_module[local_port];
 
 		mlxsw_sp_port_create(mlxsw_sp, local_port, false, module,

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -152,7 +152,7 @@ struct mlxsw_sp {
 	const struct mlxsw_bus_info *bus_info;
 	unsigned char base_mac[ETH_ALEN];
 	struct mlxsw_sp_upper *lags;
-	u8 *port_to_module;
+	int *port_to_module;
 	struct mlxsw_sp_sb *sb;
 	struct mlxsw_sp_bridge *bridge;
 	struct mlxsw_sp_router *router;