From 09e0c3bbde901f17837ad5088a13c3985534b860 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Mon, 7 Aug 2023 22:33:14 +0300 Subject: [PATCH] net/sched: taprio: don't access q->qdiscs[] in unoffloaded mode during attach() This is a simple code transformation with no intended behavior change, just to make it absolutely clear that q->qdiscs[] is only attached to the child taprio classes in full offload mode. Right now we use the q->qdiscs[] variable in taprio_attach() for software mode too, but that is quite confusing and avoidable. We use it only to reach the netdev TX queue, but we could as well just use netdev_get_tx_queue() for that. Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20230807193324.4128292-2-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski --- net/sched/sch_taprio.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 8c9cfff..1cbc7fc 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -2145,14 +2145,20 @@ static void taprio_attach(struct Qdisc *sch) /* Attach underlying qdisc */ for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { - struct Qdisc *qdisc = q->qdiscs[ntx]; + struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, ntx); struct Qdisc *old; if (FULL_OFFLOAD_IS_ENABLED(q->flags)) { + struct Qdisc *qdisc = q->qdiscs[ntx]; + qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; - old = dev_graft_qdisc(qdisc->dev_queue, qdisc); + old = dev_graft_qdisc(dev_queue, qdisc); } else { - old = dev_graft_qdisc(qdisc->dev_queue, sch); + /* In software mode, attach the root taprio qdisc + * to all netdev TX queues, so that dev_qdisc_enqueue() + * goes through taprio_enqueue(). + */ + old = dev_graft_qdisc(dev_queue, sch); qdisc_refcount_inc(sch); } if (old) -- 2.7.4