netdev - [PATCH net-next v2 08/15] net: sched: act_simple: remove dependency on rtnl lock

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Date:   Fri, 10 Aug 2018 20:51:48 +0300
From:   Vlad Buslov <vladbu@...lanox.com>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, jhs@...atatu.com, xiyou.wangcong@...il.com,
        jiri@...nulli.us, pablo@...filter.org, kadlec@...ckhole.kfki.hu,
        fw@...len.de, ast@...nel.org, daniel@...earbox.net,
        edumazet@...gle.com, keescook@...omium.org,
        marcelo.leitner@...il.com, Vlad Buslov <vladbu@...lanox.com>
Subject: [PATCH net-next v2 08/15] net: sched: act_simple: remove dependency on rtnl lock

Use tcf spinlock to protect private simple action data from concurrent
modification during dump. (simple init already uses tcf spinlock when
changing action state)

Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
---
 net/sched/act_simple.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index aa51152e0066..18e4452574cd 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -156,10 +156,11 @@ static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 		.index   = d->tcf_index,
 		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
-		.action  = d->tcf_action,
 	};
 	struct tcf_t t;
 
+	spin_lock_bh(&d->tcf_lock);
+	opt.action = d->tcf_action;
 	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 		goto nla_put_failure;
@@ -167,9 +168,12 @@ static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 	tcf_tm_dump(&t, &d->tcf_tm);
 	if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 		goto nla_put_failure;
+	spin_unlock_bh(&d->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&d->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5