Commit c85cedb3 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net_sched: sch_skbprio: implement lockless skbprio_dump() 



Instead of relying on RTNL, skbprio_dump() can use READ_ONCE()
annotation, paired with WRITE_ONCE() one in skbprio_change().

Also add a READ_ONCE(sch->limit) in skbprio_enqueue().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6c00dc4f

net/sched/sch_skbprio.c

+5 −3
Original line number Diff line number Diff line
@@ -79,7 +79,9 @@ static int skbprio_enqueue(struct sk_buff *skb, struct Qdisc *sch, 
	prio = min(skb->priority, max_priority);



	qdisc = &q->qdiscs[prio];

	if (sch->q.qlen < sch->limit) {



	/* sch->limit can change under us from skbprio_change() */

	if (sch->q.qlen < READ_ONCE(sch->limit)) {

		__skb_queue_tail(qdisc, skb);

		qdisc_qstats_backlog_inc(sch, skb);

		q->qstats[prio].backlog += qdisc_pkt_len(skb);
@@ -172,7 +174,7 @@ static int skbprio_change(struct Qdisc *sch, struct nlattr *opt, 
	if (opt->nla_len != nla_attr_size(sizeof(*ctl)))

		return -EINVAL;



	sch->limit = ctl->limit;

	WRITE_ONCE(sch->limit, ctl->limit);

	return 0;

}
@@ -200,7 +202,7 @@ static int skbprio_dump(struct Qdisc *sch, struct sk_buff *skb) 
{

	struct tc_skbprio_qopt opt;



	opt.limit = sch->limit;

	opt.limit = READ_ONCE(sch->limit);



	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))

		return -1;