Subject: Re: [PATCH net-next v3 1/2] cxgb4: add TC-MATCHALL classifier egress offload

From: Rahul Lakkireddy <[email-masked]>
Date: Fri, 15 Nov 2019 20:38:30 +0530

On Friday, November 11/15/19, 2019 at 14:58:45 +0100, Jiri Pirko wrote:
> Fri, Nov 15, 2019 at 01:14:20PM CET, [email-masked] wrote:
> 
> [...]
> 
> 
> >+static int cxgb4_matchall_egress_validate(struct net_device *dev,
> >+					  struct tc_cls_matchall_offload *cls)
> >+{
> >+	struct netlink_ext_ack *extack = cls->common.extack;
> >+	struct flow_action *actions = &cls->rule->action;
> >+	struct port_info *pi = netdev2pinfo(dev);
> >+	struct flow_action_entry *entry;
> >+	u64 max_link_rate;
> >+	u32 i, speed;
> >+	int ret;
> >+
> >+	if (cls->common.prio != 1) {
> >+		NL_SET_ERR_MSG_MOD(extack,
> >+				   "Egress MATCHALL offload must have prio 1");
> 
> I don't understand why you need it to be prio 1.

This is to maintain rule ordering with the kernel. Jakub has suggested
this in my earlier series [1][2]. I see similar checks in various
drivers (mlx5 and nfp), while offloading matchall with policer.

[1] http://patchwork.ozlabs.org/patch/1194936/#2304413
[2] http://patchwork.ozlabs.org/patch/1194301/#2303749

Thanks,
Rahul