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

From: "Volodymyr Mytnyk [C]" <vmytnyk@marvell.com>
To: Ido Schimmel <idosch@idosch.org>,
	Vadym Kochan <vadym.kochan@plvision.eu>
Cc: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jamal Hadi Salim <jhs@mojatatu.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>, Vladimir Oltean <olteanv@gmail.com>,
	Serhiy Boiko <serhiy.boiko@plvision.eu>,
	Volodymyr Mytnyk <volodymyr.mytnyk@plvision.eu>,
	Taras Chornyi <taras.chornyi@plvision.eu>,
	"Taras Chornyi [C]" <tchornyi@marvell.com>,
	Mickey Rachamim <mickeyr@marvell.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Vadym Kochan [C]" <vkochan@marvell.com>
Subject: Re: [PATCH net-next v2 4/4] net: marvell: prestera: Offload FLOW_ACTION_POLICE
Date: Tue, 3 Aug 2021 16:19:03 +0000	[thread overview]
Message-ID: <SJ0PR18MB4009243B42CB9A03C2C35647B2F09@SJ0PR18MB4009.namprd18.prod.outlook.com> (raw)
In-Reply-To: <YQgN1djql6wOk8dc@shredder>

Hi Ido,

Thanks for the review. Pls see the comments inline.

> 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.

Agree, it makes sense.

>
> 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.

Each rule has a different policer assigned by HW. Do you mean the police.index should be checked here ?

>
> > +                     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?

This is HW traffic class used for packets that are trapped to CPU port. The usage is as the following:

tc qdisc add dev DEV clsact
tc filter add dev DEV ingress flower skip_sw dst_mac 00:AA:AA:AA:AA:00 hw_tc 1 action trap

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

This is not support at this moment by the driver, so it is always zero now.