net: sched: flower: use correct ht function to prevent duplicates

Implementation of function rhashtable_insert_fast() check if its internal
helper function __rhashtable_insert_fast() returns non-NULL pointer and
seemingly return -EEXIST in such case. However, since
__rhashtable_insert_fast() is called with NULL key pointer, it never
actually checks for duplicates, which means that -EEXIST is never returned
to the user. Use rhashtable_lookup_insert_fast() hash table API instead. In
order to verify that it works as expected and prevent the problem from
happening in future, extend tc-tests with new test that verifies that no
new filters with existing key can be inserted to flower classifier.

Fixes: 1f17f7742eeb ("net: sched: flower: insert filter to ht before offloading it to hw")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 2763176e369c..9cd8122a5c38 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1466,9 +1466,9 @@ static int fl_ht_insert_unique(struct cls_fl_filter *fnew,
         struct fl_flow_mask *mask = fnew->mask;
         int err;
 
-        err = rhashtable_insert_fast(&mask->ht,
-                                     &fnew->ht_node,
-                                     mask->filter_ht_params);
+        err = rhashtable_lookup_insert_fast(&mask->ht,
+                                            &fnew->ht_node,
+                                            mask->filter_ht_params);
         if (err) {
                 *in_ht = false;
                 /* It is okay if filter with same key exists when