net_sched: get rid of unnecessary dev_qdisc_reset() (759ae57f) · Commits · 戴 / test

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>

net/sched/sch_generic.c

+0 −16

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}

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