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Commit 256d61b8 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NET_SCHED]: Fix endless loops (part 4): HTB 



Convert HTB to use qdisc_tree_decrease_len() and add a callback
for deactivating a class when its child queue becomes empty.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f973b913

net/sched/sch_htb.c

+17 −7
Original line number Diff line number Diff line
@@ -1230,11 +1230,7 @@ static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 
			return -ENOBUFS;

		sch_tree_lock(sch);

		if ((*old = xchg(&cl->un.leaf.q, new)) != NULL) {

			if (cl->prio_activity)

				htb_deactivate(qdisc_priv(sch), cl);



			/* TODO: is it correct ? Why CBQ doesn't do it ? */

			sch->q.qlen -= (*old)->q.qlen;

			qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);

			qdisc_reset(*old);

		}

		sch_tree_unlock(sch);
@@ -1249,6 +1245,14 @@ static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg) 
	return (cl && !cl->level) ? cl->un.leaf.q : NULL;

}



static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)

{

	struct htb_class *cl = (struct htb_class *)arg;



	if (cl->un.leaf.q->q.qlen == 0)

		htb_deactivate(qdisc_priv(sch), cl);

}



static unsigned long htb_get(struct Qdisc *sch, u32 classid)

{

	struct htb_class *cl = htb_find(classid, sch);
@@ -1323,6 +1327,7 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg) 
{

	struct htb_sched *q = qdisc_priv(sch);

	struct htb_class *cl = (struct htb_class *)arg;

	unsigned int qlen;



	// TODO: why don't allow to delete subtree ? references ? does

	// tc subsys quarantee us that in htb_destroy it holds no class
@@ -1336,8 +1341,9 @@ static int htb_delete(struct Qdisc *sch, unsigned long arg) 
	hlist_del_init(&cl->hlist);



	if (!cl->level) {

		sch->q.qlen -= cl->un.leaf.q->q.qlen;

		qlen = cl->un.leaf.q->q.qlen;

		qdisc_reset(cl->un.leaf.q);

		qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);

	}



	if (cl->prio_activity)
@@ -1419,8 +1425,11 @@ static int htb_change_class(struct Qdisc *sch, u32 classid, 
		new_q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, classid);

		sch_tree_lock(sch);

		if (parent && !parent->level) {

			unsigned int qlen = parent->un.leaf.q->q.qlen;



			/* turn parent into inner node */

			sch->q.qlen -= parent->un.leaf.q->q.qlen;

			qdisc_reset(parent->un.leaf.q);

			qdisc_tree_decrease_qlen(parent->un.leaf.q, qlen);

			qdisc_destroy(parent->un.leaf.q);

			if (parent->prio_activity)

				htb_deactivate(q, parent);
@@ -1568,6 +1577,7 @@ static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg) 
static struct Qdisc_class_ops htb_class_ops = {

	.graft		=	htb_graft,

	.leaf		=	htb_leaf,

	.qlen_notify	=	htb_qlen_notify,

	.get		=	htb_get,

	.put		=	htb_put,

	.change		=	htb_change_class,