net: sched: register noqueue qdisc

This way users can attach noqueue just like any other qdisc using tc
without having to mess with tx_queue_len first.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sch_generic.h

@@ -340,6 +340,7 @@ extern struct Qdisc noop_qdisc;
 extern struct Qdisc_ops noop_qdisc_ops;
 extern struct Qdisc_ops pfifo_fast_ops;
 extern struct Qdisc_ops mq_qdisc_ops;
+extern struct Qdisc_ops noqueue_qdisc_ops;
 extern const struct Qdisc_ops *default_qdisc_ops;
 
 struct Qdisc_class_common {

net/sched/sch_api.c

@@ -1942,6 +1942,7 @@ static int __init pktsched_init(void)
 	register_qdisc(&bfifo_qdisc_ops);
 	register_qdisc(&pfifo_head_drop_qdisc_ops);
 	register_qdisc(&mq_qdisc_ops);
+	register_qdisc(&noqueue_qdisc_ops);
 
 	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, NULL);
 	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, NULL);

net/sched/sch_generic.c

@@ -416,9 +416,19 @@ struct Qdisc noop_qdisc = {
 };
 EXPORT_SYMBOL(noop_qdisc);
 
-static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
+static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt)
+{
+	/* register_qdisc() assigns a default of noop_enqueue if unset,
+	 * but __dev_queue_xmit() treats noqueue only as such
+	 * if this is NULL - so clear it here. */
+	qdisc->enqueue = NULL;
+	return 0;
+}
+
+struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
 	.id		=	"noqueue",
 	.priv_size	=	0,
+	.init		=	noqueue_init,
 	.enqueue	=	noop_enqueue,
 	.dequeue	=	noop_dequeue,
 	.peek		=	noop_dequeue,