net_sched: make qdisc_tree_decrease_qlen() work for non mq

Stas Nichiporovich reported a regression in his HFSC qdisc setup
on a non multi queue device.

It turns out I mistakenly added a TCQ_F_NOPARENT flag on all qdisc
allocated in qdisc_create() for non multi queue devices, which was
rather buggy. I was clearly mislead by the TCQ_F_ONETXQUEUE that is
also set here for no good reason, since it only matters for the root
qdisc.

Fixes: 4eaf3b84f288 ("net_sched: fix qdisc_tree_decrease_qlen() races")
Reported-by: Stas Nichiporovich <stasn77@gmail.com>
Tested-by: Stas Nichiporovich <stasn77@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 7ec667dd4ce1d01deef3698af8c291da0722a657..b5c2cf2aa6d4bc00e5c4bac2b3326db3d785c8be 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -950,7 +950,7 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
                }
                lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);
                if (!netif_is_multiqueue(dev))
-                       sch->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
+                       sch->flags |= TCQ_F_ONETXQUEUE;
        }
 
        sch->handle = handle;