net_sched: remove a bogus warning in hfsc

In update_vf():

  cftree_remove(cl);
  update_cfmin(cl->cl_parent);

the cl_cfmin of cl->cl_parent is intentionally updated to 0
when that parent only has one child. And if this parent is
root qdisc, we could end up, in hfsc_schedule_watchdog(),
that we can't decide the next schedule time for qdisc watchdog.
But it seems safe that we can just skip it, as this watchdog is
not always scheduled anyway.

Thanks to Marco for testing all the cases, nothing is broken.

Reported-by: Marco Berizzi <pupilla@libero.it>
Tested-by: Marco Berizzi <pupilla@libero.it>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 3ae9877ea2057d0ba517c84d38f6ba6a79ff6ef8..3278a76f6861576ba7e42cf9f91a62f96443cb3a 100644 (file)
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1385,8 +1385,8 @@ hfsc_schedule_watchdog(struct Qdisc *sch)
                if (next_time == 0 || next_time > q->root.cl_cfmin)
                        next_time = q->root.cl_cfmin;
        }
-       WARN_ON(next_time == 0);
-       qdisc_watchdog_schedule(&q->watchdog, next_time);
+       if (next_time)
+               qdisc_watchdog_schedule(&q->watchdog, next_time);
 }
 
 static int