net: sch: api: add extack support in qdisc_create_dflt

This patch adds extack support for the function qdisc_create_dflt which is
a common used function in the tc subsystem. Callers which are interested
in the receiving error can assign extack to get a more detailed
information why qdisc_create_dflt failed. The function qdisc_create_dflt
will also call an init callback which can fail by any per-qdisc specific
handling.

Cc: David Ahern <dsahern@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index a4f21c0..e2c75f5 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -89,7 +89,8 @@ extern struct Qdisc_ops pfifo_head_drop_qdisc_ops;
 
 int fifo_set_limit(struct Qdisc *q, unsigned int limit);
 struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
-			       unsigned int limit);
+			       unsigned int limit,
+			       struct netlink_ext_ack *extack);
 
 int register_qdisc(struct Qdisc_ops *qops);
 int unregister_qdisc(struct Qdisc_ops *qops);