From d7728495665601658c7f94f3b5fa4e3f54d71c18 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Fri, 10 Aug 2018 20:51:47 +0300 Subject: [PATCH] net: sched: act_sample: remove dependency on rtnl lock Use tcf spinlock to protect private sample action data from concurrent modification during dump and init. Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller --- net/sched/act_sample.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c index 2608ccc83e5e..81071afe1b43 100644 --- a/net/sched/act_sample.c +++ b/net/sched/act_sample.c @@ -80,11 +80,13 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla, } s = to_sample(*a); + spin_lock(&s->tcf_lock); s->tcf_action = parm->action; s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]); s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]); psample_group = psample_group_get(net, s->psample_group_num); if (!psample_group) { + spin_unlock(&s->tcf_lock); tcf_idr_release(*a, bind); return -ENOMEM; } @@ -94,6 +96,7 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla, s->truncate = true; s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]); } + spin_unlock(&s->tcf_lock); if (ret == ACT_P_CREATED) tcf_idr_insert(tn, *a); @@ -105,7 +108,8 @@ static void tcf_sample_cleanup(struct tc_action *a) struct tcf_sample *s = to_sample(a); struct psample_group *psample_group; - psample_group = rtnl_dereference(s->psample_group); + /* last reference to action, no need to lock */ + psample_group = rcu_dereference_protected(s->psample_group, 1); RCU_INIT_POINTER(s->psample_group, NULL); if (psample_group) psample_group_put(psample_group); @@ -174,12 +178,13 @@ static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, struct tcf_sample *s = to_sample(a); struct tc_sample opt = { .index = s->tcf_index, - .action = s->tcf_action, .refcnt = refcount_read(&s->tcf_refcnt) - ref, .bindcnt = atomic_read(&s->tcf_bindcnt) - bind, }; struct tcf_t t; + spin_lock(&s->tcf_lock); + opt.action = s->tcf_action; if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt)) goto nla_put_failure; @@ -196,9 +201,12 @@ static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a, if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num)) goto nla_put_failure; + spin_unlock(&s->tcf_lock); + return skb->len; nla_put_failure: + spin_unlock(&s->tcf_lock); nlmsg_trim(skb, b); return -1; }