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

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[ Upstream commit 379349e9bc3b42b8b2f8f7a03f64a97623fff323 ]

This reverts commit ba27b4cdaaa66561aaedb2101876e563738d36fe

Ahmed reported ouf-of-order issues bisected to commit ba27b4cdaaa6
("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: ba27b4cdaaa6 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paolo Abeni 2020-02-18 18:15:44 +01:00 committed by Greg Kroah-Hartman
parent 129a1e235c
commit 63d5320a0c
1 changed files with 2 additions and 20 deletions
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22
net/core/dev.c
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@ -3386,26 +3386,8 @@ 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);
}
rc = q->enqueue(skb, q, &to_free) & NET_XMIT_MASK;
qdisc_run(q);
if (unlikely(to_free))
kfree_skb_list(to_free);