linux-kernel - [PATCH 5.15 006/102] net: mscc: ocelot: fix last VCAP IS1/IS2 filter persisting in hardware when deleted

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Message-Id: <20220516193624.176861912@linuxfoundation.org>
Date:   Mon, 16 May 2022 21:35:40 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vladimir Oltean <vladimir.oltean@....com>,
        Jakub Kicinski <kuba@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 006/102] net: mscc: ocelot: fix last VCAP IS1/IS2 filter persisting in hardware when deleted

From: Vladimir Oltean <vladimir.oltean@....com>

[ Upstream commit 16bbebd35629c93a8c68c6d8d28557e100bcee73 ]

ocelot_vcap_filter_del() works by moving the next filters over the
current one, and then deleting the last filter by calling vcap_entry_set()
with a del_filter which was specially created by memsetting its memory
to zeroes. vcap_entry_set() then programs this to the TCAM and action
RAM via the cache registers.

The problem is that vcap_entry_set() is a dispatch function which looks
at del_filter->block_id. But since del_filter is zeroized memory, the
block_id is 0, or otherwise said, VCAP_ES0. So practically, what we do
is delete the entry at the same TCAM index from VCAP ES0 instead of IS1
or IS2.

The code was not always like this. vcap_entry_set() used to simply be
is2_entry_set(), and then, the logic used to work.

Restore the functionality by populating the block_id of the del_filter
based on the VCAP block of the filter that we're deleting. This makes
vcap_entry_set() know what to do.

Fixes: 1397a2eb52e2 ("net: mscc: ocelot: create TCAM skeleton from tc filter chains")
Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/ethernet/mscc/ocelot_vcap.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/mscc/ocelot_vcap.c b/drivers/net/ethernet/mscc/ocelot_vcap.c
index 99d7376a70a7..f5f513d87642 100644
--- a/drivers/net/ethernet/mscc/ocelot_vcap.c
+++ b/drivers/net/ethernet/mscc/ocelot_vcap.c
@@ -1192,7 +1192,11 @@ int ocelot_vcap_filter_del(struct ocelot *ocelot,
 	struct ocelot_vcap_filter del_filter;
 	int i, index;

+	/* Need to inherit the block_id so that vcap_entry_set()
+	 * does not get confused and knows where to install it.
+	 */
 	memset(&del_filter, 0, sizeof(del_filter));
+	del_filter.block_id = filter->block_id;

 	/* Gets index of the filter */
 	index = ocelot_vcap_block_get_filter_index(block, filter);
-- 
2.35.1