Subject: [PATCH AUTOSEL 5.13 034/189] net/sched: cls_api: increase max_reclassify_loop

From: Sasha Levin <[email-masked]>
Date: Tue, 6 Jul 2021 07:11:34 -0400

From: Davide Caratti <[email-masked]>

[ 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 <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/sched/cls_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 279f9e2a2319..d73b5c5514a9 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1531,7 +1531,7 @@ 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;
 
-- 
2.30.2