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net_sched: get rid of unnecessary dev_qdisc_reset() 

Resetting old qdisc on dev_queue->qdisc_sleeping in
dev_qdisc_reset() is redundant, because this qdisc,
even if not same with dev_queue->qdisc, is reset via
qdisc_put() right after calling dev_graft_qdisc() when
hitting refcnt 0.

This is very easy to observe with qdisc_reset() tracepoint
and stack traces.

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>
This commit is contained in:
Cong Wang 2020-05-26 21:35:27 -07:00 committed by David S. Miller
parent 70f5096533
commit 759ae57f1b
1 changed files with 0 additions and 16 deletions
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16
net/sched/sch_generic.c
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@ -1191,16 +1191,6 @@ static bool some_qdisc_is_busy(struct net_device *dev)
return false;
}
static void dev_qdisc_reset(struct net_device *dev,
struct netdev_queue *dev_queue,
void *none)
{
struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
if (qdisc)
qdisc_reset(qdisc);
}
/**
* dev_deactivate_many - deactivate transmissions on several devices
* @head: list of devices to deactivate
@ -1237,12 +1227,6 @@ void dev_deactivate_many(struct list_head *head)
*/
schedule_timeout_uninterruptible(1);
}
/* The new qdisc is assigned at this point so we can safely
* unwind stale skb lists and qdisc statistics
*/
netdev_for_each_tx_queue(dev, dev_qdisc_reset, NULL);
if (dev_ingress_queue(dev))
dev_qdisc_reset(dev, dev_ingress_queue(dev), NULL);
}
}