From 25089d330b0c2e23d8503f2a0f2d072471bdcec8 Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Thu, 5 May 2022 02:55:02 +0300
Subject: [PATCH 16/34] net: mscc: ocelot: restrict tc-trap actions to VCAP IS2
 lookup 0
Git-commit: 477d2b91623e682e9a8126ea92acb8f684969cc7
Patch-mainline: v5.18-rc7
References: git-fixes

Once the CPU port was added to the destination port mask of a packet, it
can never be cleared, so even packets marked as dropped by the MASK_MODE
of a VCAP IS2 filter will still reach it. This is why we need the
OCELOT_POLICER_DISCARD to "kill dropped packets dead" and make software
stop seeing them.

We disallow policer rules from being put on any other chain than the one
for the first lookup, but we don't do this for "drop" rules, although we
should. This change is merely ascertaining that the rules dont't
(completely) work and letting the user know.

The blamed commit is the one that introduced the multi-chain architecture
in ocelot. Prior to that, we should have always offloaded the filters to
VCAP IS2 lookup 0, where they did work.

Fixes: 1397a2eb52e2 ("net: mscc: ocelot: create TCAM skeleton from tc filter chains")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/mscc/ocelot_flower.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot_flower.c b/drivers/net/ethernet/mscc/ocelot_flower.c
index c6c88d50b0ee..9389cb24cab0 100644
--- a/drivers/net/ethernet/mscc/ocelot_flower.c
+++ b/drivers/net/ethernet/mscc/ocelot_flower.c
@@ -206,9 +206,10 @@ static int ocelot_flower_parse_action(struct ocelot *ocelot, int port,
 			filter->type = OCELOT_VCAP_FILTER_OFFLOAD;
 			break;
 		case FLOW_ACTION_TRAP:
-			if (filter->block_id != VCAP_IS2) {
+			if (filter->block_id != VCAP_IS2 ||
+			    filter->lookup != 0) {
 				NL_SET_ERR_MSG_MOD(extack,
-						   "Trap action can only be offloaded to VCAP IS2");
+						   "Trap action can only be offloaded to VCAP IS2 lookup 0");
 				return -EOPNOTSUPP;
 			}
 			if (filter->goto_target != -1) {
-- 
2.16.4