[PATCH 5.10 043/137] cxgb4: fix regression with HASH tc prio value update

From: Greg Kroah-Hartman
Date: Tue Jun 08 2021 - 15:04:35 EST


From: Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx>

[ Upstream commit a27fb314cba8cb84cd6456a4699c3330a83c326d ]

commit db43b30cd89c ("cxgb4: add ethtool n-tuple filter deletion")
has moved searching for next highest priority HASH filter rule to
cxgb4_flow_rule_destroy(), which searches the rhashtable before the
the rule is removed from it and hence always finds at least 1 entry.
Fix by removing the rule from rhashtable first before calling
cxgb4_flow_rule_destroy() and hence avoid fetching stale info.

Fixes: db43b30cd89c ("cxgb4: add ethtool n-tuple filter deletion")
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
.../net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
index 1b88bd1c2dbe..dd9be229819a 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_tc_flower.c
@@ -997,20 +997,16 @@ int cxgb4_tc_flower_destroy(struct net_device *dev,
if (!ch_flower)
return -ENOENT;

+ rhashtable_remove_fast(&adap->flower_tbl, &ch_flower->node,
+ adap->flower_ht_params);
+
ret = cxgb4_flow_rule_destroy(dev, ch_flower->fs.tc_prio,
&ch_flower->fs, ch_flower->filter_id);
if (ret)
- goto err;
+ netdev_err(dev, "Flow rule destroy failed for tid: %u, ret: %d",
+ ch_flower->filter_id, ret);

- ret = rhashtable_remove_fast(&adap->flower_tbl, &ch_flower->node,
- adap->flower_ht_params);
- if (ret) {
- netdev_err(dev, "Flow remove from rhashtable failed");
- goto err;
- }
kfree_rcu(ch_flower, rcu);
-
-err:
return ret;
}

--
2.30.2