[PATCH 4.3 43/55] net_sched: make qdisc_tree_decrease_qlen() work for non mq

From: Greg Kroah-Hartman
Date: Wed Jan 20 2016 - 19:51:38 EST

4.3-stable review patch. If anyone has any objections, please let me know.


From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 225734de70cd0a9e0b978f3583a4a87939271d5e ]

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

Fixes: 4eaf3b84f288 ("net_sched: fix qdisc_tree_decrease_qlen() races")
Reported-by: Stas Nichiporovich <stasn77@xxxxxxxxx>
Tested-by: Stas Nichiporovich <stasn77@xxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/sched/sch_api.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -950,7 +950,7 @@ qdisc_create(struct net_device *dev, str
lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);
if (!netif_is_multiqueue(dev))
+ sch->flags |= TCQ_F_ONETXQUEUE;

sch->handle = handle;