tree 69c247ac88bc588611f280bf684ae0a707523c63
parent 59bcaed5f71f002d39d151ccd387dd0f226e00f2
author Eric Dumazet <edumazet@google.com> 1386891716 -0800
committer David S. Miller <davem@davemloft.net> 1387002006 -0500

pkt_sched: set root qdisc before change() in attach_default_qdiscs()

After commit 95dc19299f74 ("pkt_sched: give visibility to mq slave
qdiscs") we call disc_list_add() while the device qdisc might be
the noop_qdisc one.

This shows up as duplicates in "tc qdisc show", as all inactive devices
point to noop_qdisc.

Fix this by setting dev->qdisc to the new qdisc before calling
ops->change() in attach_default_qdiscs()

Add a WARN_ON_ONCE() to catch any future similar problem.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>