From: Vlad Buslov <vladbu@mellanox.com>
Date: Wed, 30 Oct 2019 16:09:03 +0200
Subject: net: sched: don't expose action qstats to skb_tc_reinsert()
Patch-mainline: v5.5-rc1
Git-commit: ef816f3c49c1c404ababc50e10d4cbe5109da678
References: bsc#1154353

Previous commit introduced helper function for updating qstats and
refactored set of actions to use the helpers, instead of modifying qstats
directly. However, one of the affected action exposes its qstats to
skb_tc_reinsert(), which then modifies it.

Refactor skb_tc_reinsert() to return integer error code and don't increment
overlimit qstats in case of error, and use the returned error code in
tcf_mirred_act() to manually increment the overlimit counter with new
helper function.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/net/sch_generic.h |   12 ++----------
 net/sched/act_mirred.c    |    4 ++--
 2 files changed, 4 insertions(+), 12 deletions(-)

--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -1290,17 +1290,9 @@ void mini_qdisc_pair_swap(struct mini_Qd
 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
 			  struct mini_Qdisc __rcu **p_miniq);
 
-static inline void skb_tc_reinsert(struct sk_buff *skb, struct tcf_result *res)
+static inline int skb_tc_reinsert(struct sk_buff *skb, struct tcf_result *res)
 {
-	struct gnet_stats_queue *stats = res->qstats;
-	int ret;
-
-	if (res->ingress)
-		ret = netif_receive_skb(skb);
-	else
-		ret = dev_queue_xmit(skb);
-	if (ret && stats)
-		qstats_overlimit_inc(res->qstats);
+	return res->ingress ? netif_receive_skb(skb) : dev_queue_xmit(skb);
 }
 
 #endif
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -289,8 +289,8 @@ static int tcf_mirred_act(struct sk_buff
 		/* let's the caller reinsert the packet, if possible */
 		if (use_reinsert) {
 			res->ingress = want_ingress;
-			res->qstats = this_cpu_ptr(m->common.cpu_qstats);
-			skb_tc_reinsert(skb, res);
+			if (skb_tc_reinsert(skb, res))
+				tcf_action_inc_overlimit_qstats(&m->common);
 			__this_cpu_dec(mirred_rec_level);
 			return TC_ACT_CONSUMED;
 		}