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Message-ID: <20240418073248.2952954-11-edumazet@google.com>
Date: Thu, 18 Apr 2024 07:32:44 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: Jamal Hadi Salim <jhs@...atatu.com>, Simon Horman <horms@...nel.org>,
"Toke Høiland-Jørgensen" <toke@...hat.com>, Cong Wang <xiyou.wangcong@...il.com>,
Jiri Pirko <jiri@...nulli.us>, netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v2 net-next 10/14] 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@...gle.com>
Reviewed-by: Simon Horman <horms@...nel.org>
---
net/sched/sch_fq_pie.c | 61 +++++++++++++++++++++++-------------------
1 file changed, 34 insertions(+), 27 deletions(-)
diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index 358cf304f4c91203749bac10f6e9154eda0a3778..c38f33ff80bde74cfe33de7558f66e5962ffe56b 100644
--- a/net/sched/sch_fq_pie.c
+++ b/net/sched/sch_fq_pie.c
@@ -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);
--
2.44.0.683.g7961c838ac-goog
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