From: Jiri Pirko <jiri@mellanox.com>
Date: Thu, 31 Oct 2019 11:42:10 +0200
Subject: mlxsw: spectrum: Distinguish between unsplittable and split port
Patch-mainline: v5.5-rc1
Git-commit: 26a6befa5df79dddb1a1c464b5758de9d618ee23
References: bsc#1154488

Currently when user does split, he is not able to distinguish if the
port cannot be split because it is already split, or because it cannot
be split at all. Add another check for split flag to distinguish this.
Also add check forbidding split when maximal width is 1.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Shalom Toledo <shalomt@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -4118,6 +4118,13 @@ static int mlxsw_sp_port_split(struct ml
 		return -EINVAL;
 	}
 
+	/* Split ports cannot be split. */
+	if (mlxsw_sp_port->split) {
+		netdev_err(mlxsw_sp_port->dev, "Port cannot be split further\n");
+		NL_SET_ERR_MSG_MOD(extack, "Port cannot be split further");
+		return -EINVAL;
+	}
+
 	module = mlxsw_sp_port->mapping.module;
 
 	max_width = mlxsw_core_module_max_width(mlxsw_core,
@@ -4128,10 +4135,10 @@ static int mlxsw_sp_port_split(struct ml
 		return max_width;
 	}
 
-	/* Split port with non-max module width cannot be split. */
-	if (mlxsw_sp_port->mapping.width != max_width) {
-		netdev_err(mlxsw_sp_port->dev, "Port cannot be split further\n");
-		NL_SET_ERR_MSG_MOD(extack, "Port cannot be split further");
+	/* Split port with non-max and 1 module width cannot be split. */
+	if (mlxsw_sp_port->mapping.width != max_width || max_width == 1) {
+		netdev_err(mlxsw_sp_port->dev, "Port cannot be split\n");
+		NL_SET_ERR_MSG_MOD(extack, "Port cannot be split");
 		return -EINVAL;
 	}