Commit 379349e9 authored Feb 18, 2020 by Paolo Abeni Committed by David S. Miller Feb 18, 2020

Revert "net: dev: introduce support for sch BYPASS for lockless qdisc"



This reverts commit ba27b4cd

Ahmed reported ouf-of-order issues bisected to commit ba27b4cd
("net: dev: introduce support for sch BYPASS for lockless qdisc").
I can't find any working solution other than a plain revert.

This will introduce some minor performance regressions for
pfifo_fast qdisc. I plan to address them in net-next with more
indirect call wrapper boilerplate for qdiscs.

Reported-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Fixes: ba27b4cd ("net: dev: introduce support for sch BYPASS for lockless qdisc")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 29f20dd6

net/core/dev.c

+2 −20

Original line number	Diff line number	Diff line
		@@ -3662,26 +3662,8 @@ static inline int __dev_xmit_skb(struct sk_buff skb, struct Qdisc q,
		qdisc_calculate_pkt_len(skb, q);

		if (q->flags & TCQ_F_NOLOCK) {
		if ((q->flags & TCQ_F_CAN_BYPASS) && READ_ONCE(q->empty) &&
		qdisc_run_begin(q)) {
		if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED,
		&q->state))) {
		__qdisc_drop(skb, &to_free);
		rc = NET_XMIT_DROP;
		goto end_run;
		}
		qdisc_bstats_cpu_update(q, skb);

		rc = NET_XMIT_SUCCESS;
		if (sch_direct_xmit(skb, q, dev, txq, NULL, true))
		__qdisc_run(q);

		end_run:
		qdisc_run_end(q);
		} else {
		rc = q->enqueue(skb, q, &to_free) & NET_XMIT_MASK;
		qdisc_run(q);
		}

		if (unlikely(to_free))
		kfree_skb_list(to_free);

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