From: Shalom Toledo <shalomt@mellanox.com>
Date: Mon, 16 Sep 2019 18:04:20 +0300
Subject: mlxsw: spectrum_buffers: Prevent changing CPU port's configuration
Patch-mainline: v5.4-rc1
Git-commit: 9d0aa053ea68cdf1ee68dc1e558f9e525d76b2ea
References: bsc#1154488

Next patch is going to register the CPU port with devlink, but only so
that the CPU port's shared buffer configuration and occupancy could be
queried.

Prevent changing CPU port's shared buffer threshold and binding
configuration.

Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Acked-by: Jiri Pirko <jiri@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_buffers.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
@@ -1085,6 +1085,11 @@ int mlxsw_sp_sb_port_pool_set(struct mlx
 	u32 max_buff;
 	int err;
 
+	if (local_port == MLXSW_PORT_CPU_PORT) {
+		NL_SET_ERR_MSG_MOD(extack, "Changing CPU port's threshold is forbidden");
+		return -EINVAL;
+	}
+
 	err = mlxsw_sp_sb_threshold_in(mlxsw_sp, pool_index,
 				       threshold, &max_buff, extack);
 	if (err)
@@ -1130,6 +1135,11 @@ int mlxsw_sp_sb_tc_pool_bind_set(struct
 	u32 max_buff;
 	int err;
 
+	if (local_port == MLXSW_PORT_CPU_PORT) {
+		NL_SET_ERR_MSG_MOD(extack, "Changing CPU port's binding is forbidden");
+		return -EINVAL;
+	}
+
 	if (dir != mlxsw_sp->sb_vals->pool_dess[pool_index].dir) {
 		NL_SET_ERR_MSG_MOD(extack, "Binding egress TC to ingress pool and vice versa is forbidden");
 		return -EINVAL;