net/sched: cls_api: increase max_reclassify_loop

[ Upstream commit 05ff8435e50569a0a6b95e5ceaea43696e8827ab ]

modern userspace applications, like OVN, can configure the TC datapath to
"recirculate" packets several times. If more than 4 "recirculation" rules
are configured, packets can be dropped by __tcf_classify().
Changing the maximum number of reclassifications (from 4 to 16) should be
sufficient to prevent drops in most use cases, and guard against loops at
the same time.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index a281da0..3009079 100644 (file)
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1532,7 +1532,7 @@ static inline int __tcf_classify(struct sk_buff *skb,
                                 u32 *last_executed_chain)
 {
 #ifdef CONFIG_NET_CLS_ACT
-       const int max_reclassify_loop = 4;
+       const int max_reclassify_loop = 16;
        const struct tcf_proto *first_tp;
        int limit = 0;