Commit 18cdd2f0 authored by Vladimir Oltean's avatar Vladimir Oltean Committed by Jakub Kicinski
Browse files

net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex 



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: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c8cbe123

net/sched/sch_taprio.c

+4 −10
Original line number Diff line number Diff line
@@ -1484,10 +1484,8 @@ 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))
@@ -1878,9 +1876,8 @@ 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));
@@ -1924,8 +1921,6 @@ 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:
@@ -1935,7 +1930,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) 
	nla_nest_cancel(skb, nest);



start_error:

	rcu_read_unlock();

	return -ENOSPC;

}