Re: [PATCH net-next v2 4/4] net: marvell: prestera: Offload FLOW_ACTION_POLICE

[Ido Schimmel]

On Mon, Aug 02, 2021 at 05:08:49PM +0300, Vadym Kochan wrote:
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_flower.c b/drivers/net/ethernet/marvell/prestera/prestera_flower.c
> index e571ba09ec08..76f30856ac98 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_flower.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_flower.c
> @@ -5,6 +5,8 @@
>  #include "prestera_acl.h"
>  #include "prestera_flower.h"
>  
> +#define PRESTERA_HW_TC_NUM	8
> +
>  static int prestera_flower_parse_actions(struct prestera_flow_block *block,
>  					 struct prestera_acl_rule *rule,
>  					 struct flow_action *flow_action,
> @@ -30,6 +32,11 @@ static int prestera_flower_parse_actions(struct prestera_flow_block *block,
>  		case FLOW_ACTION_TRAP:
>  			a_entry.id = PRESTERA_ACL_RULE_ACTION_TRAP;
>  			break;
> +		case FLOW_ACTION_POLICE:
> +			a_entry.id = PRESTERA_ACL_RULE_ACTION_POLICE;
> +			a_entry.police.rate = act->police.rate_bytes_ps;
> +			a_entry.police.burst = act->police.burst;

If packet rate based policing is not supported, an error should be
returned here with extack.

It seems the implementation assumes that each rule has a different
policer, so an error should be returned in case the same policer is
shared between different rules.

> +			break;
>  		default:
>  			NL_SET_ERR_MSG_MOD(extack, "Unsupported action");
>  			pr_err("Unsupported action\n");
> @@ -110,6 +117,17 @@ static int prestera_flower_parse(struct prestera_flow_block *block,
>  		return -EOPNOTSUPP;
>  	}
>  
> +	if (f->classid) {
> +		int hw_tc = __tc_classid_to_hwtc(PRESTERA_HW_TC_NUM, f->classid);
> +
> +		if (hw_tc < 0) {
> +			NL_SET_ERR_MSG_MOD(f->common.extack, "Unsupported HW TC");
> +			return hw_tc;
> +		}
> +
> +		prestera_acl_rule_hw_tc_set(rule, hw_tc);
> +	}

Not sure what this is. Can you show a command line example of how this
is used?

What about visibility regarding number of packets that were dropped by
the policer?