[PATCH net-next v2 1/3] mlxsw: spectrum_buffers: Prevent changing CPU port's configuration

[Ido Schimmel <idosch@idosch.org>]

From: Shalom Toledo <shalomt@mellanox.com>

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>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
index 888ba4300bcc..f1dbde73fa78 100644
--- 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 mlxsw_core_port *mlxsw_core_port,
 	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 mlxsw_core_port *mlxsw_core_port,
 	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;
-- 
2.21.0