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authorCong Wang <xiyou.wangcong@gmail.com>2020-05-26 21:35:26 -0700
committerDavid S. Miller <davem@davemloft.net>2020-05-27 15:05:49 -0700
commit70f50965338a12e17454c31ad5ece27069719358 (patch)
tree6fbefb496398d793022646a147b760964106addb /net/sched/sch_generic.c
parentf5a7833e83628f18c1ee94e6ffcb1d232f029be9 (diff)
downloadlwn-70f50965338a12e17454c31ad5ece27069719358.tar.gz
lwn-70f50965338a12e17454c31ad5ece27069719358.zip
net_sched: avoid resetting active qdisc for multiple times
Except for sch_mq and sch_mqprio, each dev queue points to the same root qdisc, so when we reset the dev queues with netdev_for_each_tx_queue() we end up resetting the same instance of the root qdisc for multiple times. Avoid this by checking the __QDISC_STATE_DEACTIVATED bit in each iteration, so for sch_mq/sch_mqprio, we still reset all of them like before, for the rest, we only reset it once. Reported-by: Václav Zindulka <vaclav.zindulka@tlapnet.cz> Tested-by: Václav Zindulka <vaclav.zindulka@tlapnet.cz> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_generic.c')
-rw-r--r--net/sched/sch_generic.c37
1 files changed, 23 insertions, 14 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index a4271e47f220..d13e27467470 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1128,6 +1128,28 @@ void dev_activate(struct net_device *dev)
}
EXPORT_SYMBOL(dev_activate);
+static void qdisc_deactivate(struct Qdisc *qdisc)
+{
+ bool nolock = qdisc->flags & TCQ_F_NOLOCK;
+
+ if (qdisc->flags & TCQ_F_BUILTIN)
+ return;
+ if (test_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state))
+ return;
+
+ if (nolock)
+ spin_lock_bh(&qdisc->seqlock);
+ spin_lock_bh(qdisc_lock(qdisc));
+
+ set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
+
+ qdisc_reset(qdisc);
+
+ spin_unlock_bh(qdisc_lock(qdisc));
+ if (nolock)
+ spin_unlock_bh(&qdisc->seqlock);
+}
+
static void dev_deactivate_queue(struct net_device *dev,
struct netdev_queue *dev_queue,
void *_qdisc_default)
@@ -1137,21 +1159,8 @@ static void dev_deactivate_queue(struct net_device *dev,
qdisc = rtnl_dereference(dev_queue->qdisc);
if (qdisc) {
- bool nolock = qdisc->flags & TCQ_F_NOLOCK;
-
- if (nolock)
- spin_lock_bh(&qdisc->seqlock);
- spin_lock_bh(qdisc_lock(qdisc));
-
- if (!(qdisc->flags & TCQ_F_BUILTIN))
- set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
-
+ qdisc_deactivate(qdisc);
rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
- qdisc_reset(qdisc);
-
- spin_unlock_bh(qdisc_lock(qdisc));
- if (nolock)
- spin_unlock_bh(&qdisc->seqlock);
}
}