On Mon, Nov 2, 2020 at 11:24 PM Yunsheng Lin <linyunsh...@huawei.com> wrote:
> >> From my understanding, we can do anything about the old qdisc (including
> >> destorying the old qdisc) after some_qdisc_is_busy() return false.
> >
> > But the current code does the reset _before_ some_qdisc_is_busy(). ;)
>
> If lock is taken when doing reset, it does not matter if the reset is
> before some_qdisc_is_busy(), right?
Why not? How about the following scenario?
CPU0: CPU1:
dev_reset_queue()
net_tx_action()
-> sch_direct_xmit()
-> dev_requeue_skb()
some_qdisc_is_busy()
// waiting for TX action on CPU1
// now some packets are requeued
