diff mbox series

[v3,net-next,03/10] net/sched: taprio: try again to report q->qdiscs[] to qdisc_leaf()

Message ID 20230801182421.1997560-4-vladimir.oltean@nxp.com
State Handled Elsewhere
Headers show
Series Improve the taprio qdisc's relationship with its children | expand

Commit Message

Vladimir Oltean Aug. 1, 2023, 6:24 p.m. UTC 
This is another stab at commit 1461d212ab27 ("net/sched: taprio: make
qdisc_leaf() see the per-netdev-queue pfifo child qdiscs"), later
reverted in commit af7b29b1deaa ("Revert "net/sched: taprio: make
qdisc_leaf() see the per-netdev-queue pfifo child qdiscs"").

I believe that the problems that caused the revert were fixed, and thus,
this change is identical to the original patch.

Its purpose is to properly reject attaching a software taprio child
qdisc to a software taprio parent. Because unoffloaded taprio currently
reports itself (the root Qdisc) as the return value from qdisc_leaf(),
then the process of attaching another taprio as child to a Qdisc class
of the root will just result in a Qdisc_ops :: change() call for the
root. Whereas that's not we want. We want Qdisc_ops :: init() to be
called for the taprio child, in order to give the taprio child a chance
to check whether its sch->parent is TC_H_ROOT or not (and reject this
configuration).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v2->v3: none
v1->v2: rebase on top of rtnl_dereference() change for txq->qdisc_sleeping

 net/sched/sch_taprio.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 41944197876a..c9ad585b5dc7 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -2442,12 +2442,14 @@  static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 
 static struct Qdisc *taprio_leaf(struct Qdisc *sch, unsigned long cl)
 {
-	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	unsigned int ntx = cl - 1;
 
-	if (!dev_queue)
+	if (ntx >= dev->num_tx_queues)
 		return NULL;
 
-	return rtnl_dereference(dev_queue->qdisc_sleeping);
+	return q->qdiscs[ntx];
 }
 
 static unsigned long taprio_find(struct Qdisc *sch, u32 classid)