[PATCH 5.17 007/114] net: mscc: ocelot: fix last VCAP IS1/IS2 filter persisting in hardware when deleted

Greg Kroah-Hartman
2022-05-16T20:29:51Z

From: Vladimir Oltean <vladimir.oltean@nxp.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@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.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 d3544413a8a4..e650afef12af 100644
--- a/drivers/net/ethernet/mscc/ocelot_vcap.c
+++ b/drivers/net/ethernet/mscc/ocelot_vcap.c
@@ -1221,7 +1221,11 @@ 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