net_sched: sch_fq_pie: implement lockless fq_pie_dump()

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

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2024-04-18 07:32:44 +00:00 committed by David S. Miller
parent 396a003850
commit 13a9965de3

View File

@ -299,8 +299,8 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
if (tb[TCA_FQ_PIE_LIMIT]) {
u32 limit = nla_get_u32(tb[TCA_FQ_PIE_LIMIT]);
q->p_params.limit = limit;
sch->limit = limit;
WRITE_ONCE(q->p_params.limit, limit);
WRITE_ONCE(sch->limit, limit);
}
if (tb[TCA_FQ_PIE_FLOWS]) {
if (q->flows) {
@ -322,39 +322,45 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
u32 target = nla_get_u32(tb[TCA_FQ_PIE_TARGET]);
/* convert to pschedtime */
q->p_params.target =
PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC);
WRITE_ONCE(q->p_params.target,
PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC));
}
/* tupdate is in jiffies */
if (tb[TCA_FQ_PIE_TUPDATE])
q->p_params.tupdate =
usecs_to_jiffies(nla_get_u32(tb[TCA_FQ_PIE_TUPDATE]));
WRITE_ONCE(q->p_params.tupdate,
usecs_to_jiffies(nla_get_u32(tb[TCA_FQ_PIE_TUPDATE])));
if (tb[TCA_FQ_PIE_ALPHA])
q->p_params.alpha = nla_get_u32(tb[TCA_FQ_PIE_ALPHA]);
WRITE_ONCE(q->p_params.alpha,
nla_get_u32(tb[TCA_FQ_PIE_ALPHA]));
if (tb[TCA_FQ_PIE_BETA])
q->p_params.beta = nla_get_u32(tb[TCA_FQ_PIE_BETA]);
WRITE_ONCE(q->p_params.beta,
nla_get_u32(tb[TCA_FQ_PIE_BETA]));
if (tb[TCA_FQ_PIE_QUANTUM])
q->quantum = nla_get_u32(tb[TCA_FQ_PIE_QUANTUM]);
WRITE_ONCE(q->quantum, nla_get_u32(tb[TCA_FQ_PIE_QUANTUM]));
if (tb[TCA_FQ_PIE_MEMORY_LIMIT])
q->memory_limit = nla_get_u32(tb[TCA_FQ_PIE_MEMORY_LIMIT]);
WRITE_ONCE(q->memory_limit,
nla_get_u32(tb[TCA_FQ_PIE_MEMORY_LIMIT]));
if (tb[TCA_FQ_PIE_ECN_PROB])
q->ecn_prob = nla_get_u32(tb[TCA_FQ_PIE_ECN_PROB]);
WRITE_ONCE(q->ecn_prob,
nla_get_u32(tb[TCA_FQ_PIE_ECN_PROB]));
if (tb[TCA_FQ_PIE_ECN])
q->p_params.ecn = nla_get_u32(tb[TCA_FQ_PIE_ECN]);
WRITE_ONCE(q->p_params.ecn,
nla_get_u32(tb[TCA_FQ_PIE_ECN]));
if (tb[TCA_FQ_PIE_BYTEMODE])
q->p_params.bytemode = nla_get_u32(tb[TCA_FQ_PIE_BYTEMODE]);
WRITE_ONCE(q->p_params.bytemode,
nla_get_u32(tb[TCA_FQ_PIE_BYTEMODE]));
if (tb[TCA_FQ_PIE_DQ_RATE_ESTIMATOR])
q->p_params.dq_rate_estimator =
nla_get_u32(tb[TCA_FQ_PIE_DQ_RATE_ESTIMATOR]);
WRITE_ONCE(q->p_params.dq_rate_estimator,
nla_get_u32(tb[TCA_FQ_PIE_DQ_RATE_ESTIMATOR]));
/* Drop excess packets if new limit is lower */
while (sch->q.qlen > sch->limit) {
@ -471,22 +477,23 @@ static int fq_pie_dump(struct Qdisc *sch, struct sk_buff *skb)
return -EMSGSIZE;
/* convert target from pschedtime to us */
if (nla_put_u32(skb, TCA_FQ_PIE_LIMIT, sch->limit) ||
nla_put_u32(skb, TCA_FQ_PIE_FLOWS, q->flows_cnt) ||
if (nla_put_u32(skb, TCA_FQ_PIE_LIMIT, READ_ONCE(sch->limit)) ||
nla_put_u32(skb, TCA_FQ_PIE_FLOWS, READ_ONCE(q->flows_cnt)) ||
nla_put_u32(skb, TCA_FQ_PIE_TARGET,
((u32)PSCHED_TICKS2NS(q->p_params.target)) /
((u32)PSCHED_TICKS2NS(READ_ONCE(q->p_params.target))) /
NSEC_PER_USEC) ||
nla_put_u32(skb, TCA_FQ_PIE_TUPDATE,
jiffies_to_usecs(q->p_params.tupdate)) ||
nla_put_u32(skb, TCA_FQ_PIE_ALPHA, q->p_params.alpha) ||
nla_put_u32(skb, TCA_FQ_PIE_BETA, q->p_params.beta) ||
nla_put_u32(skb, TCA_FQ_PIE_QUANTUM, q->quantum) ||
nla_put_u32(skb, TCA_FQ_PIE_MEMORY_LIMIT, q->memory_limit) ||
nla_put_u32(skb, TCA_FQ_PIE_ECN_PROB, q->ecn_prob) ||
nla_put_u32(skb, TCA_FQ_PIE_ECN, q->p_params.ecn) ||
nla_put_u32(skb, TCA_FQ_PIE_BYTEMODE, q->p_params.bytemode) ||
jiffies_to_usecs(READ_ONCE(q->p_params.tupdate))) ||
nla_put_u32(skb, TCA_FQ_PIE_ALPHA, READ_ONCE(q->p_params.alpha)) ||
nla_put_u32(skb, TCA_FQ_PIE_BETA, READ_ONCE(q->p_params.beta)) ||
nla_put_u32(skb, TCA_FQ_PIE_QUANTUM, READ_ONCE(q->quantum)) ||
nla_put_u32(skb, TCA_FQ_PIE_MEMORY_LIMIT,
READ_ONCE(q->memory_limit)) ||
nla_put_u32(skb, TCA_FQ_PIE_ECN_PROB, READ_ONCE(q->ecn_prob)) ||
nla_put_u32(skb, TCA_FQ_PIE_ECN, READ_ONCE(q->p_params.ecn)) ||
nla_put_u32(skb, TCA_FQ_PIE_BYTEMODE, READ_ONCE(q->p_params.bytemode)) ||
nla_put_u32(skb, TCA_FQ_PIE_DQ_RATE_ESTIMATOR,
q->p_params.dq_rate_estimator))
READ_ONCE(q->p_params.dq_rate_estimator)))
goto nla_put_failure;
return nla_nest_end(skb, opts);