On Wed, Nov 4, 2020 at 10:04 PM Cong Wang <xiyou.wangc...@gmail.com> wrote: > > 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
Never mind, the skb_bad_txq is also cleared by dev_reset_queue(). TX action after resetting should get NULL. Thanks.
