Commit 293c7e2b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net_sched: sch_hhf: implement lockless hhf_dump() 



Instead of relying on RTNL, hhf_dump() can use READ_ONCE()
annotations, paired with WRITE_ONCE() ones in hhf_change().

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 49e8ae53

net/sched/sch_hhf.c

+21 −14
Original line number Diff line number Diff line
@@ -534,27 +534,31 @@ static int hhf_change(struct Qdisc *sch, struct nlattr *opt, 
	sch_tree_lock(sch);



	if (tb[TCA_HHF_BACKLOG_LIMIT])

		sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);

		WRITE_ONCE(sch->limit, nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]));



	q->quantum = new_quantum;

	q->hhf_non_hh_weight = new_hhf_non_hh_weight;

	WRITE_ONCE(q->quantum, new_quantum);

	WRITE_ONCE(q->hhf_non_hh_weight, new_hhf_non_hh_weight);



	if (tb[TCA_HHF_HH_FLOWS_LIMIT])

		q->hh_flows_limit = nla_get_u32(tb[TCA_HHF_HH_FLOWS_LIMIT]);

		WRITE_ONCE(q->hh_flows_limit,

			   nla_get_u32(tb[TCA_HHF_HH_FLOWS_LIMIT]));



	if (tb[TCA_HHF_RESET_TIMEOUT]) {

		u32 us = nla_get_u32(tb[TCA_HHF_RESET_TIMEOUT]);



		q->hhf_reset_timeout = usecs_to_jiffies(us);

		WRITE_ONCE(q->hhf_reset_timeout,

			   usecs_to_jiffies(us));

	}



	if (tb[TCA_HHF_ADMIT_BYTES])

		q->hhf_admit_bytes = nla_get_u32(tb[TCA_HHF_ADMIT_BYTES]);

		WRITE_ONCE(q->hhf_admit_bytes,

			   nla_get_u32(tb[TCA_HHF_ADMIT_BYTES]));



	if (tb[TCA_HHF_EVICT_TIMEOUT]) {

		u32 us = nla_get_u32(tb[TCA_HHF_EVICT_TIMEOUT]);



		q->hhf_evict_timeout = usecs_to_jiffies(us);

		WRITE_ONCE(q->hhf_evict_timeout,

			   usecs_to_jiffies(us));

	}



	qlen = sch->q.qlen;
@@ -657,15 +661,18 @@ static int hhf_dump(struct Qdisc *sch, struct sk_buff *skb) 
	if (opts == NULL)

		goto nla_put_failure;



	if (nla_put_u32(skb, TCA_HHF_BACKLOG_LIMIT, sch->limit) ||

	    nla_put_u32(skb, TCA_HHF_QUANTUM, q->quantum) ||

	    nla_put_u32(skb, TCA_HHF_HH_FLOWS_LIMIT, q->hh_flows_limit) ||

	if (nla_put_u32(skb, TCA_HHF_BACKLOG_LIMIT, READ_ONCE(sch->limit)) ||

	    nla_put_u32(skb, TCA_HHF_QUANTUM, READ_ONCE(q->quantum)) ||

	    nla_put_u32(skb, TCA_HHF_HH_FLOWS_LIMIT,

			READ_ONCE(q->hh_flows_limit)) ||

	    nla_put_u32(skb, TCA_HHF_RESET_TIMEOUT,

			jiffies_to_usecs(q->hhf_reset_timeout)) ||

	    nla_put_u32(skb, TCA_HHF_ADMIT_BYTES, q->hhf_admit_bytes) ||

			jiffies_to_usecs(READ_ONCE(q->hhf_reset_timeout))) ||

	    nla_put_u32(skb, TCA_HHF_ADMIT_BYTES,

			READ_ONCE(q->hhf_admit_bytes)) ||

	    nla_put_u32(skb, TCA_HHF_EVICT_TIMEOUT,

			jiffies_to_usecs(q->hhf_evict_timeout)) ||

	    nla_put_u32(skb, TCA_HHF_NON_HH_WEIGHT, q->hhf_non_hh_weight))

			jiffies_to_usecs(READ_ONCE(q->hhf_evict_timeout))) ||

	    nla_put_u32(skb, TCA_HHF_NON_HH_WEIGHT,

			READ_ONCE(q->hhf_non_hh_weight)))

		goto nla_put_failure;



	return nla_nest_end(skb, opts);