Re: [PATCH net-next] mlxsw: spectrum_flower: Do not allow mixing sample and mirror actions

[Michal Swiatkowski <michal.swiatkowski@linux.intel.com>]

On Tue, Dec 10, 2024 at 10:45:37AM +0100, Petr Machata wrote:
> From: Ido Schimmel <idosch@nvidia.com>
> 
> The device does not support multiple mirror actions per rule and the
> driver rejects such configuration:
> 
>  # tc filter add dev swp1 ingress pref 1 proto ip flower skip_sw action mirred egress mirror dev swp2 action mirred egress mirror dev swp3
>  Error: mlxsw_spectrum: Multiple mirror actions per rule are not supported.
>  We have an error talking to the kernel
> 
> Internally, the sample action is implemented by the device by mirroring
> to the CPU port. Therefore, mixing sample and mirror actions in a single
> rule does not work correctly and results in the last action effect.
> 
> Solve by rejecting such misconfiguration:
> 
>  # tc filter add dev swp1 ingress pref 1 proto ip flower skip_sw action mirred egress mirror dev swp2 action sample rate 100 group 1
>  Error: mlxsw_spectrum: Sample action after mirror action is not supported.
>  We have an error talking to the kernel
> 
>  # tc filter add dev swp1 ingress pref 1 proto ip flower skip_sw action sample rate 100 group 1 action mirred egress mirror dev swp2
>  Error: mlxsw_spectrum: Mirror action after sample action is not supported.
>  We have an error talking to the kernel
> 
> Reported-by: Vladyslav Mykhaliuk <vmykhaliuk@nvidia.com>
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> Reviewed-by: Amit Cohen <amcohen@nvidia.com>
> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> ---
>  drivers/net/ethernet/mellanox/mlxsw/spectrum_flower.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_flower.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_flower.c
> index f07955b5439f..6a4a81c63451 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_flower.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_flower.c
> @@ -192,6 +192,11 @@ static int mlxsw_sp_flower_parse_actions(struct mlxsw_sp *mlxsw_sp,
>  				return -EOPNOTSUPP;
>  			}
>  
> +			if (sample_act_count) {
> +				NL_SET_ERR_MSG_MOD(extack, "Mirror action after sample action is not supported");
> +				return -EOPNOTSUPP;
> +			}
> +
>  			err = mlxsw_sp_acl_rulei_act_mirror(mlxsw_sp, rulei,
>  							    block, out_dev,
>  							    extack);
> @@ -265,6 +270,11 @@ static int mlxsw_sp_flower_parse_actions(struct mlxsw_sp *mlxsw_sp,
>  				return -EOPNOTSUPP;
>  			}
>  
> +			if (mirror_act_count) {
> +				NL_SET_ERR_MSG_MOD(extack, "Sample action after mirror action is not supported");
> +				return -EOPNOTSUPP;
> +			}
> +
>  			err = mlxsw_sp_acl_rulei_act_sample(mlxsw_sp, rulei,
>  							    block,
>  							    act->sample.psample_group,
> -- 
> 2.47.0

Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>

Thanks