From 2540e0511ea17e25831be543cdf9381e6209950d Mon Sep 17 00:00:00 2001 From: Jarek Poplawski Date: Thu, 21 Aug 2008 05:11:14 -0700 Subject: [PATCH] pkt_sched: Fix qdisc_watchdog() vs. dev_deactivate() race dev_deactivate() can skip rescheduling of a qdisc by qdisc_watchdog() or other timer calling netif_schedule() after dev_queue_deactivate(). We prevent this checking aliveness before scheduling the timer. Since during deactivation the root qdisc is available only as qdisc_sleeping additional accessor qdisc_root_sleeping() is created. With feedback from Herbert Xu Signed-off-by: Jarek Poplawski Signed-off-by: David S. Miller --- include/net/sch_generic.h | 5 +++++ net/sched/sch_api.c | 4 ++++ net/sched/sch_cbq.c | 4 ++++ 3 files changed, 13 insertions(+) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 84d25f2e6188..b1d2cfea89c5 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -193,6 +193,11 @@ static inline struct Qdisc *qdisc_root(struct Qdisc *qdisc) return qdisc->dev_queue->qdisc; } +static inline struct Qdisc *qdisc_root_sleeping(struct Qdisc *qdisc) +{ + return qdisc->dev_queue->qdisc_sleeping; +} + /* The qdisc root lock is a mechanism by which to top level * of a qdisc tree can be locked from any qdisc node in the * forest. This allows changing the configuration of some diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index ef0efeca6352..45f442d7de47 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -444,6 +444,10 @@ void qdisc_watchdog_schedule(struct qdisc_watchdog *wd, psched_time_t expires) { ktime_t time; + if (test_bit(__QDISC_STATE_DEACTIVATED, + &qdisc_root_sleeping(wd->qdisc)->state)) + return; + wd->qdisc->flags |= TCQ_F_THROTTLED; time = ktime_set(0, 0); time = ktime_add_ns(time, PSCHED_US2NS(expires)); diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c index 47ef492c4ff4..8fa90d68ec6d 100644 --- a/net/sched/sch_cbq.c +++ b/net/sched/sch_cbq.c @@ -521,6 +521,10 @@ static void cbq_ovl_delay(struct cbq_class *cl) struct cbq_sched_data *q = qdisc_priv(cl->qdisc); psched_tdiff_t delay = cl->undertime - q->now; + if (test_bit(__QDISC_STATE_DEACTIVATED, + &qdisc_root_sleeping(cl->qdisc)->state)) + return; + if (!cl->delayed) { psched_time_t sched = q->now; ktime_t expires; -- 2.20.1