netdev - [PATCH net-next 03/14] net: sched: act_gact: remove dependency on rtnl lock

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Date:   Mon,  6 Aug 2018 09:54:14 +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 03/14] net: sched: act_gact: remove dependency on rtnl lock

Use tcf spinlock to protect gact action private state from concurrent
modification during dump and init. Remove rtnl assertion that is no longer
necessary.

Signed-off-by: Vlad Buslov <vladbu@...lanox.com>
---
 net/sched/act_gact.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index 661b72b9147d..bfccd34a3968 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -113,7 +113,7 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 
 	gact = to_gact(*a);
 
-	ASSERT_RTNL();
+	spin_lock(&gact->tcf_lock);
 	gact->tcf_action = parm->action;
 #ifdef CONFIG_GACT_PROB
 	if (p_parm) {
@@ -126,6 +126,8 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 		gact->tcfg_ptype   = p_parm->ptype;
 	}
 #endif
+	spin_unlock(&gact->tcf_lock);
+
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
 	return ret;
@@ -178,10 +180,11 @@ static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 		.index   = gact->tcf_index,
 		.refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
-		.action  = gact->tcf_action,
 	};
 	struct tcf_t t;
 
+	spin_lock(&gact->tcf_lock);
+	opt.action = gact->tcf_action;
 	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 #ifdef CONFIG_GACT_PROB
@@ -199,9 +202,12 @@ static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 	tcf_tm_dump(&t, &gact->tcf_tm);
 	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 		goto nla_put_failure;
+	spin_unlock(&gact->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&gact->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5