On 17-06-13 04:36 PM, Cong Wang wrote:
Laura reported a sleep-in-atomic kernel warning inside tcf_act_police_init() which calls gen_replace_estimator() with spinlock protection.It is not necessary in this case, we already have RTNL lock here so it is enough to protect concurrent writers. For the reader, i.e. tcf_act_police(), it needs to make decision based on this rate estimator, in the worst case we drop more/less packets than necessary while changing the rate in parallel, it is still acceptable. Reported-by: Laura Abbott <labb...@redhat.com> Reported-by: Nick Huber <nicholashu...@gmail.com> Cc: Jamal Hadi Salim <j...@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com> --- net/sched/act_police.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/net/sched/act_police.c b/net/sched/act_police.c index f42008b..b062bc8 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -132,21 +132,21 @@ static int tcf_act_police_init(struct net *net, struct nlattr *nla, } }- spin_lock_bh(&police->tcf_lock);if (est) { err = gen_replace_estimator(&police->tcf_bstats, NULL, &police->tcf_rate_est, &police->tcf_lock, NULL, est); if (err) - goto failure_unlock; + goto failure; } else if (tb[TCA_POLICE_AVRATE] && (ret == ACT_P_CREATED || !gen_estimator_active(&police->tcf_rate_est))) { err = -EINVAL; - goto failure_unlock; + goto failure; }+ spin_lock_bh(&police->tcf_lock);/* No failure allowed after this point */ police->tcfp_mtu = parm->mtu; if (police->tcfp_mtu == 0) { @@ -192,8 +192,6 @@ static int tcf_act_police_init(struct net *net, struct nlattr *nla,return ret; -failure_unlock:- spin_unlock_bh(&police->tcf_lock); failure: qdisc_put_rtab(P_tab); qdisc_put_rtab(R_tab);
Looks good to me. Acked-by: Jamal Hadi Salim <j...@mojatatu.com> cheers, jamal
