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Message-Id: <20221009221453.1216158-52-sashal@kernel.org>
Date: Sun, 9 Oct 2022 18:14:30 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Vladimir Oltean <vladimir.oltean@....com>,
Jakub Kicinski <kuba@...nel.org>,
Sasha Levin <sashal@...nel.org>, vinicius.gomes@...el.com,
jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 5.19 52/73] net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex
From: Vladimir Oltean <vladimir.oltean@....com>
[ Upstream commit 18cdd2f0998a4967b1fff4c43ed9aef049e42c39 ]
Since the writer-side lock is taken here, we do not need to open an RCU
read-side critical section, instead we can use rtnl_dereference() to
tell lockdep we are serialized with concurrent writes.
Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
net/sched/sch_taprio.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 86675a79da1e..71408136d4a0 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -1492,10 +1492,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
}
INIT_LIST_HEAD(&new_admin->entries);
- rcu_read_lock();
- oper = rcu_dereference(q->oper_sched);
- admin = rcu_dereference(q->admin_sched);
- rcu_read_unlock();
+ oper = rtnl_dereference(q->oper_sched);
+ admin = rtnl_dereference(q->admin_sched);
/* no changes - no new mqprio settings */
if (!taprio_mqprio_cmp(dev, mqprio))
@@ -1888,9 +1886,8 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
struct nlattr *nest, *sched_nest;
unsigned int i;
- rcu_read_lock();
- oper = rcu_dereference(q->oper_sched);
- admin = rcu_dereference(q->admin_sched);
+ oper = rtnl_dereference(q->oper_sched);
+ admin = rtnl_dereference(q->admin_sched);
opt.num_tc = netdev_get_num_tc(dev);
memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
@@ -1934,8 +1931,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
nla_nest_end(skb, sched_nest);
done:
- rcu_read_unlock();
-
return nla_nest_end(skb, nest);
admin_error:
@@ -1945,7 +1940,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
nla_nest_cancel(skb, nest);
start_error:
- rcu_read_unlock();
return -ENOSPC;
}
--
2.35.1
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