sch_htb: make htb_qlen_notify() idempotent

commit 5ba8b837b522d7051ef81bacf3d95383ff8edce5 upstream.

htb_qlen_notify() always deactivates the HTB class and in fact could
trigger a warning if it is already deactivated. Therefore, it is not
idempotent and not friendly to its callers, like fq_codel_dequeue().

Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers'
life.

Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250403211033.166059-2-xiyou.wangcong@gmail.com
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Siddh Raman Pant <siddh.raman.pant@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 568754731d4268fd4b0345340aa1a9c2c4fa66a8..89687be5797857f159ba1b3618086f2f6d45f228 100644 (file)
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1173,6 +1173,8 @@ static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
 {
        struct htb_class *cl = (struct htb_class *)arg;
 
+       if (!cl->prio_activity)
+               return;
        htb_deactivate(qdisc_priv(sch), cl);
 }