[net-next-2.6.git] / net / sched / sch_drr.c

/*
 * net/sched/sch_drr.c         Deficit Round Robin scheduler
 *
 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/pkt_sched.h>
#include <net/sch_generic.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>

struct drr_class {
	struct Qdisc_class_common	common;
	unsigned int			refcnt;
	unsigned int			filter_cnt;

	struct gnet_stats_basic		bstats;
	struct gnet_stats_queue		qstats;
	struct gnet_stats_rate_est	rate_est;
	struct list_head		alist;
	struct Qdisc			*qdisc;

	u32				quantum;
	u32				deficit;
};

struct drr_sched {
	struct list_head		active;
	struct tcf_proto		*filter_list;
	struct Qdisc_class_hash		clhash;
};

static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct Qdisc_class_common *clc;

	clc = qdisc_class_find(&q->clhash, classid);
	if (clc == NULL)
		return NULL;
	return container_of(clc, struct drr_class, common);
}

static void drr_purge_queue(struct drr_class *cl)
{
	unsigned int len = cl->qdisc->q.qlen;

	qdisc_reset(cl->qdisc);
	qdisc_tree_decrease_qlen(cl->qdisc, len);
}

static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
	[TCA_DRR_QUANTUM]	= { .type = NLA_U32 },
};

static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
			    struct nlattr **tca, unsigned long *arg)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl = (struct drr_class *)*arg;
	struct nlattr *tb[TCA_DRR_MAX + 1];
	u32 quantum;
	int err;

	err = nla_parse_nested(tb, TCA_DRR_MAX, tca[TCA_OPTIONS], drr_policy);
	if (err < 0)
		return err;

	if (tb[TCA_DRR_QUANTUM]) {
		quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
		if (quantum == 0)
			return -EINVAL;
	} else
		quantum = psched_mtu(qdisc_dev(sch));

	if (cl != NULL) {
		sch_tree_lock(sch);
		if (tb[TCA_DRR_QUANTUM])
			cl->quantum = quantum;
		sch_tree_unlock(sch);

		if (tca[TCA_RATE])
			gen_replace_estimator(&cl->bstats, &cl->rate_est,
					      qdisc_root_sleeping_lock(sch),
					      tca[TCA_RATE]);
		return 0;
	}

	cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
	if (cl == NULL)
		return -ENOBUFS;

	cl->refcnt	   = 1;
	cl->common.classid = classid;
	cl->quantum	   = quantum;
	cl->qdisc	   = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
					       &pfifo_qdisc_ops, classid);
	if (cl->qdisc == NULL)
		cl->qdisc = &noop_qdisc;

	if (tca[TCA_RATE])
		gen_replace_estimator(&cl->bstats, &cl->rate_est,
				      qdisc_root_sleeping_lock(sch),
				      tca[TCA_RATE]);

	sch_tree_lock(sch);
	qdisc_class_hash_insert(&q->clhash, &cl->common);
	sch_tree_unlock(sch);

	qdisc_class_hash_grow(sch, &q->clhash);

	*arg = (unsigned long)cl;
	return 0;
}

static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
{
	gen_kill_estimator(&cl->bstats, &cl->rate_est);
	qdisc_destroy(cl->qdisc);
	kfree(cl);
}

static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl = (struct drr_class *)arg;

	if (cl->filter_cnt > 0)
		return -EBUSY;

	sch_tree_lock(sch);

	drr_purge_queue(cl);
	qdisc_class_hash_remove(&q->clhash, &cl->common);

	if (--cl->refcnt == 0)
		drr_destroy_class(sch, cl);

	sch_tree_unlock(sch);
	return 0;
}

static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
{
	struct drr_class *cl = drr_find_class(sch, classid);

	if (cl != NULL)
		cl->refcnt++;

	return (unsigned long)cl;
}

static void drr_put_class(struct Qdisc *sch, unsigned long arg)
{
	struct drr_class *cl = (struct drr_class *)arg;

	if (--cl->refcnt == 0)
		drr_destroy_class(sch, cl);
}

static struct tcf_proto **drr_tcf_chain(struct Qdisc *sch, unsigned long cl)
{
	struct drr_sched *q = qdisc_priv(sch);

	if (cl)
		return NULL;

	return &q->filter_list;
}

static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
				  u32 classid)
{
	struct drr_class *cl = drr_find_class(sch, classid);

	if (cl != NULL)
		cl->filter_cnt++;

	return (unsigned long)cl;
}

static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
{
	struct drr_class *cl = (struct drr_class *)arg;

	cl->filter_cnt--;
}

static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
			   struct Qdisc *new, struct Qdisc **old)
{
	struct drr_class *cl = (struct drr_class *)arg;

	if (new == NULL) {
		new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
					&pfifo_qdisc_ops, cl->common.classid);
		if (new == NULL)
			new = &noop_qdisc;
	}

	sch_tree_lock(sch);
	drr_purge_queue(cl);
	*old = cl->qdisc;
	cl->qdisc = new;
	sch_tree_unlock(sch);
	return 0;
}

static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
{
	struct drr_class *cl = (struct drr_class *)arg;

	return cl->qdisc;
}

static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
{
	struct drr_class *cl = (struct drr_class *)arg;

	if (cl->qdisc->q.qlen == 0)
		list_del(&cl->alist);
}

static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
			  struct sk_buff *skb, struct tcmsg *tcm)
{
	struct drr_class *cl = (struct drr_class *)arg;
	struct nlattr *nest;

	tcm->tcm_parent	= TC_H_ROOT;
	tcm->tcm_handle	= cl->common.classid;
	tcm->tcm_info	= cl->qdisc->handle;

	nest = nla_nest_start(skb, TCA_OPTIONS);
	if (nest == NULL)
		goto nla_put_failure;
	NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
	return nla_nest_end(skb, nest);

nla_put_failure:
	nla_nest_cancel(skb, nest);
	return -EMSGSIZE;
}

static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
				struct gnet_dump *d)
{
	struct drr_class *cl = (struct drr_class *)arg;
	struct tc_drr_stats xstats;

	memset(&xstats, 0, sizeof(xstats));
	if (cl->qdisc->q.qlen)
		xstats.deficit = cl->deficit;

	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
	    gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
		return -1;

	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
}

static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	struct hlist_node *n;
	unsigned int i;

	if (arg->stop)
		return;

	for (i = 0; i < q->clhash.hashsize; i++) {
		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
			if (arg->count < arg->skip) {
				arg->count++;
				continue;
			}
			if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
				arg->stop = 1;
				return;
			}
			arg->count++;
		}
	}
}

static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
				      int *qerr)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	struct tcf_result res;
	int result;

	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
		cl = drr_find_class(sch, skb->priority);
		if (cl != NULL)
			return cl;
	}

	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
	result = tc_classify(skb, q->filter_list, &res);
	if (result >= 0) {
#ifdef CONFIG_NET_CLS_ACT
		switch (result) {
		case TC_ACT_QUEUED:
		case TC_ACT_STOLEN:
			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
		case TC_ACT_SHOT:
			return NULL;
		}
#endif
		cl = (struct drr_class *)res.class;
		if (cl == NULL)
			cl = drr_find_class(sch, res.classid);
		return cl;
	}
	return NULL;
}

static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	unsigned int len;
	int err;

	cl = drr_classify(skb, sch, &err);
	if (cl == NULL) {
		if (err & __NET_XMIT_BYPASS)
			sch->qstats.drops++;
		kfree_skb(skb);
		return err;
	}

	len = qdisc_pkt_len(skb);
	err = qdisc_enqueue(skb, cl->qdisc);
	if (unlikely(err != NET_XMIT_SUCCESS)) {
		if (net_xmit_drop_count(err)) {
			cl->qstats.drops++;
			sch->qstats.drops++;
		}
		return err;
	}

	if (cl->qdisc->q.qlen == 1) {
		list_add_tail(&cl->alist, &q->active);
		cl->deficit = cl->quantum;
	}

	cl->bstats.packets++;
	cl->bstats.bytes += len;
	sch->bstats.packets++;
	sch->bstats.bytes += len;

	sch->q.qlen++;
	return err;
}

static struct sk_buff *drr_dequeue(struct Qdisc *sch)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	struct sk_buff *skb;
	unsigned int len;

	while (!list_empty(&q->active)) {
		cl = list_first_entry(&q->active, struct drr_class, alist);
		skb = cl->qdisc->ops->peek(cl->qdisc);
		if (skb == NULL)
			goto skip;

		len = qdisc_pkt_len(skb);
		if (len <= cl->deficit) {
			cl->deficit -= len;
			skb = qdisc_dequeue_peeked(cl->qdisc);
			if (cl->qdisc->q.qlen == 0)
				list_del(&cl->alist);
			sch->q.qlen--;
			return skb;
		}

		cl->deficit += cl->quantum;
skip:
		list_move_tail(&cl->alist, &q->active);
	}
	return NULL;
}

static unsigned int drr_drop(struct Qdisc *sch)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	unsigned int len;

	list_for_each_entry(cl, &q->active, alist) {
		if (cl->qdisc->ops->drop) {
			len = cl->qdisc->ops->drop(cl->qdisc);
			if (len > 0) {
				if (cl->qdisc->q.qlen == 0)
					list_del(&cl->alist);
				return len;
			}
		}
	}
	return 0;
}

static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
{
	struct drr_sched *q = qdisc_priv(sch);
	int err;

	err = qdisc_class_hash_init(&q->clhash);
	if (err < 0)
		return err;
	INIT_LIST_HEAD(&q->active);
	return 0;
}

static void drr_reset_qdisc(struct Qdisc *sch)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	struct hlist_node *n;
	unsigned int i;

	for (i = 0; i < q->clhash.hashsize; i++) {
		hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
			if (cl->qdisc->q.qlen)
				list_del(&cl->alist);
			qdisc_reset(cl->qdisc);
		}
	}
	sch->q.qlen = 0;
}

static void drr_destroy_qdisc(struct Qdisc *sch)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	struct hlist_node *n, *next;
	unsigned int i;

	tcf_destroy_chain(&q->filter_list);

	for (i = 0; i < q->clhash.hashsize; i++) {
		hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
					  common.hnode)
			drr_destroy_class(sch, cl);
	}
	qdisc_class_hash_destroy(&q->clhash);
}

static const struct Qdisc_class_ops drr_class_ops = {
	.change		= drr_change_class,
	.delete		= drr_delete_class,
	.get		= drr_get_class,
	.put		= drr_put_class,
	.tcf_chain	= drr_tcf_chain,
	.bind_tcf	= drr_bind_tcf,
	.unbind_tcf	= drr_unbind_tcf,
	.graft		= drr_graft_class,
	.leaf		= drr_class_leaf,
	.qlen_notify	= drr_qlen_notify,
	.dump		= drr_dump_class,
	.dump_stats	= drr_dump_class_stats,
	.walk		= drr_walk,
};

static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
	.cl_ops		= &drr_class_ops,
	.id		= "drr",
	.priv_size	= sizeof(struct drr_sched),
	.enqueue	= drr_enqueue,
	.dequeue	= drr_dequeue,
	.peek		= qdisc_peek_dequeued,
	.drop		= drr_drop,
	.init		= drr_init_qdisc,
	.reset		= drr_reset_qdisc,
	.destroy	= drr_destroy_qdisc,
	.owner		= THIS_MODULE,
};

static int __init drr_init(void)
{
	return register_qdisc(&drr_qdisc_ops);
}

static void __exit drr_exit(void)
{
	unregister_qdisc(&drr_qdisc_ops);
}

module_init(drr_init);
module_exit(drr_exit);
MODULE_LICENSE("GPL");
Commit	Line	Data
13d2a1d2 PM	1	/*
	2	* net/sched/sch_drr.c Deficit Round Robin scheduler
	3	*
	4	* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* version 2 as published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/init.h>
	13	#include <linux/errno.h>
	14	#include <linux/netdevice.h>
	15	#include <linux/pkt_sched.h>
	16	#include <net/sch_generic.h>
	17	#include <net/pkt_sched.h>
	18	#include <net/pkt_cls.h>
	19
	20	struct drr_class {
	21	struct Qdisc_class_common common;
	22	unsigned int refcnt;
	23	unsigned int filter_cnt;
	24
	25	struct gnet_stats_basic bstats;
	26	struct gnet_stats_queue qstats;
	27	struct gnet_stats_rate_est rate_est;
	28	struct list_head alist;
	29	struct Qdisc *qdisc;
	30
	31	u32 quantum;
	32	u32 deficit;
	33	};
	34
	35	struct drr_sched {
	36	struct list_head active;
	37	struct tcf_proto *filter_list;
	38	struct Qdisc_class_hash clhash;
	39	};
	40
	41	static struct drr_class drr_find_class(struct Qdisc sch, u32 classid)
	42	{
	43	struct drr_sched *q = qdisc_priv(sch);
	44	struct Qdisc_class_common *clc;
	45
	46	clc = qdisc_class_find(&q->clhash, classid);
	47	if (clc == NULL)
	48	return NULL;
	49	return container_of(clc, struct drr_class, common);
	50	}
	51
	52	static void drr_purge_queue(struct drr_class *cl)
	53	{
	54	unsigned int len = cl->qdisc->q.qlen;
	55
	56	qdisc_reset(cl->qdisc);
	57	qdisc_tree_decrease_qlen(cl->qdisc, len);
	58	}
	59
	60	static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
	61	[TCA_DRR_QUANTUM] = { .type = NLA_U32 },
	62	};
	63
	64	static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
65	struct nlattr *tca, unsigned long arg)
66	{
67	struct drr_sched *q = qdisc_priv(sch);
68	struct drr_class cl = (struct drr_class )*arg;
69	struct nlattr *tb[TCA_DRR_MAX + 1];
70	u32 quantum;
71	int err;
72
73	err = nla_parse_nested(tb, TCA_DRR_MAX, tca[TCA_OPTIONS], drr_policy);
74	if (err < 0)
75	return err;
76
77	if (tb[TCA_DRR_QUANTUM]) {
78	quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
79	if (quantum == 0)
80	return -EINVAL;
81	} else
82	quantum = psched_mtu(qdisc_dev(sch));
83
84	if (cl != NULL) {
85	sch_tree_lock(sch);
86	if (tb[TCA_DRR_QUANTUM])
87	cl->quantum = quantum;
88	sch_tree_unlock(sch);
89
90	if (tca[TCA_RATE])
91	gen_replace_estimator(&cl->bstats, &cl->rate_est,
92	qdisc_root_sleeping_lock(sch),
93	tca[TCA_RATE]);
94	return 0;
95	}
96
97	cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
98	if (cl == NULL)
99	return -ENOBUFS;
100
101	cl->refcnt = 1;
102	cl->common.classid = classid;
103	cl->quantum = quantum;
104	cl->qdisc = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
105	&pfifo_qdisc_ops, classid);
106	if (cl->qdisc == NULL)
107	cl->qdisc = &noop_qdisc;
108
109	if (tca[TCA_RATE])
110	gen_replace_estimator(&cl->bstats, &cl->rate_est,
111	qdisc_root_sleeping_lock(sch),
112	tca[TCA_RATE]);
113
114	sch_tree_lock(sch);
115	qdisc_class_hash_insert(&q->clhash, &cl->common);
116	sch_tree_unlock(sch);
117
118	qdisc_class_hash_grow(sch, &q->clhash);
119
120	*arg = (unsigned long)cl;
121	return 0;
122	}
123
124	static void drr_destroy_class(struct Qdisc sch, struct drr_class cl)
125	{
126	gen_kill_estimator(&cl->bstats, &cl->rate_est);
127	qdisc_destroy(cl->qdisc);
128	kfree(cl);
129	}
130
131	static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
132	{
133	struct drr_sched *q = qdisc_priv(sch);
134	struct drr_class cl = (struct drr_class )arg;
135
136	if (cl->filter_cnt > 0)
137	return -EBUSY;
138
139	sch_tree_lock(sch);
140
141	drr_purge_queue(cl);
142	qdisc_class_hash_remove(&q->clhash, &cl->common);
143
144	if (--cl->refcnt == 0)
145	drr_destroy_class(sch, cl);
146
147	sch_tree_unlock(sch);
148	return 0;
149	}
150
151	static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
152	{
153	struct drr_class *cl = drr_find_class(sch, classid);
154
155	if (cl != NULL)
156	cl->refcnt++;
157
158	return (unsigned long)cl;
159	}
160
161	static void drr_put_class(struct Qdisc *sch, unsigned long arg)
162	{
163	struct drr_class cl = (struct drr_class )arg;
164
165	if (--cl->refcnt == 0)
166	drr_destroy_class(sch, cl);
167	}
168
169	static struct tcf_proto *drr_tcf_chain(struct Qdisc sch, unsigned long cl)
170	{
171	struct drr_sched *q = qdisc_priv(sch);
172
173	if (cl)
174	return NULL;
175
176	return &q->filter_list;
177	}
178
179	static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
180	u32 classid)
181	{
182	struct drr_class *cl = drr_find_class(sch, classid);
183
184	if (cl != NULL)
185	cl->filter_cnt++;
186
187	return (unsigned long)cl;
188	}
189
190	static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
191	{
192	struct drr_class cl = (struct drr_class )arg;
193
194	cl->filter_cnt--;
195	}
196
197	static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
198	struct Qdisc new, struct Qdisc *old)
199	{
200	struct drr_class cl = (struct drr_class )arg;
201
202	if (new == NULL) {
203	new = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
204	&pfifo_qdisc_ops, cl->common.classid);
205	if (new == NULL)
206	new = &noop_qdisc;
207	}
208
209	sch_tree_lock(sch);
210	drr_purge_queue(cl);
b94c8afc PM	211	*old = cl->qdisc;
b94c8afc PM	212	cl->qdisc = new;
13d2a1d2 PM	213	sch_tree_unlock(sch);
	214	return 0;
	215	}
	216
	217	static struct Qdisc drr_class_leaf(struct Qdisc sch, unsigned long arg)
	218	{
	219	struct drr_class cl = (struct drr_class )arg;
	220
	221	return cl->qdisc;
	222	}
	223
	224	static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
	225	{
	226	struct drr_class cl = (struct drr_class )arg;
	227
	228	if (cl->qdisc->q.qlen == 0)
	229	list_del(&cl->alist);
	230	}
	231
	232	static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
	233	struct sk_buff skb, struct tcmsg tcm)
	234	{
	235	struct drr_class cl = (struct drr_class )arg;
	236	struct nlattr *nest;
	237
	238	tcm->tcm_parent = TC_H_ROOT;
	239	tcm->tcm_handle = cl->common.classid;
	240	tcm->tcm_info = cl->qdisc->handle;
	241
	242	nest = nla_nest_start(skb, TCA_OPTIONS);
	243	if (nest == NULL)
	244	goto nla_put_failure;
	245	NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
	246	return nla_nest_end(skb, nest);
	247
	248	nla_put_failure:
	249	nla_nest_cancel(skb, nest);
	250	return -EMSGSIZE;
	251	}
	252
	253	static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
	254	struct gnet_dump *d)
	255	{
	256	struct drr_class cl = (struct drr_class )arg;
	257	struct tc_drr_stats xstats;
	258
	259	memset(&xstats, 0, sizeof(xstats));
	260	if (cl->qdisc->q.qlen)
	261	xstats.deficit = cl->deficit;
	262
	263	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 \|\|
	264	gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 \|\|
	265	gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
	266	return -1;
	267
	268	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
	269	}
	270
	271	static void drr_walk(struct Qdisc sch, struct qdisc_walker arg)
	272	{
	273	struct drr_sched *q = qdisc_priv(sch);
	274	struct drr_class *cl;
	275	struct hlist_node *n;
	276	unsigned int i;
277
278	if (arg->stop)
279	return;
280
281	for (i = 0; i < q->clhash.hashsize; i++) {
282	hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
283	if (arg->count < arg->skip) {
284	arg->count++;
285	continue;
286	}
287	if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
288	arg->stop = 1;
289	return;
290	}
291	arg->count++;
292	}
293	}
294	}
295
296	static struct drr_class drr_classify(struct sk_buff skb, struct Qdisc *sch,
297	int *qerr)
298	{
299	struct drr_sched *q = qdisc_priv(sch);
300	struct drr_class *cl;
301	struct tcf_result res;
302	int result;
303
304	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
305	cl = drr_find_class(sch, skb->priority);
306	if (cl != NULL)
307	return cl;
308	}
309
310	*qerr = NET_XMIT_SUCCESS \| __NET_XMIT_BYPASS;
311	result = tc_classify(skb, q->filter_list, &res);
312	if (result >= 0) {
313	#ifdef CONFIG_NET_CLS_ACT
314	switch (result) {
315	case TC_ACT_QUEUED:
316	case TC_ACT_STOLEN:
317	*qerr = NET_XMIT_SUCCESS \| __NET_XMIT_STOLEN;
318	case TC_ACT_SHOT:
319	return NULL;
320	}
321	#endif
322	cl = (struct drr_class *)res.class;
323	if (cl == NULL)
324	cl = drr_find_class(sch, res.classid);
325	return cl;
326	}
327	return NULL;
328	}
329
330	static int drr_enqueue(struct sk_buff skb, struct Qdisc sch)
331	{
332	struct drr_sched *q = qdisc_priv(sch);
333	struct drr_class *cl;
334	unsigned int len;
335	int err;
336
337	cl = drr_classify(skb, sch, &err);
338	if (cl == NULL) {
339	if (err & __NET_XMIT_BYPASS)
340	sch->qstats.drops++;
341	kfree_skb(skb);
342	return err;
343	}
344
345	len = qdisc_pkt_len(skb);
346	err = qdisc_enqueue(skb, cl->qdisc);
347	if (unlikely(err != NET_XMIT_SUCCESS)) {
348	if (net_xmit_drop_count(err)) {
349	cl->qstats.drops++;
350	sch->qstats.drops++;
351	}
352	return err;
353	}
354
355	if (cl->qdisc->q.qlen == 1) {
356	list_add_tail(&cl->alist, &q->active);
357	cl->deficit = cl->quantum;
358	}
359
360	cl->bstats.packets++;
361	cl->bstats.bytes += len;
362	sch->bstats.packets++;
363	sch->bstats.bytes += len;
364
365	sch->q.qlen++;
366	return err;
367	}
368
369	static struct sk_buff drr_dequeue(struct Qdisc sch)
370	{
371	struct drr_sched *q = qdisc_priv(sch);
372	struct drr_class *cl;
373	struct sk_buff *skb;
374	unsigned int len;
375
376	while (!list_empty(&q->active)) {
377	cl = list_first_entry(&q->active, struct drr_class, alist);
378	skb = cl->qdisc->ops->peek(cl->qdisc);
379	if (skb == NULL)
380	goto skip;
381
382	len = qdisc_pkt_len(skb);
383	if (len <= cl->deficit) {
384	cl->deficit -= len;
385	skb = qdisc_dequeue_peeked(cl->qdisc);
386	if (cl->qdisc->q.qlen == 0)
387	list_del(&cl->alist);
388	sch->q.qlen--;
389	return skb;
390	}
391
392	cl->deficit += cl->quantum;
393	skip:
394	list_move_tail(&cl->alist, &q->active);
395	}
396	return NULL;
397	}
398
399	static unsigned int drr_drop(struct Qdisc *sch)
400	{
401	struct drr_sched *q = qdisc_priv(sch);
402	struct drr_class *cl;
403	unsigned int len;
404
405	list_for_each_entry(cl, &q->active, alist) {
406	if (cl->qdisc->ops->drop) {
407	len = cl->qdisc->ops->drop(cl->qdisc);
408	if (len > 0) {
409	if (cl->qdisc->q.qlen == 0)
410	list_del(&cl->alist);
411	return len;
412	}
413	}
414	}
415	return 0;
416	}
417
418	static int drr_init_qdisc(struct Qdisc sch, struct nlattr opt)
419	{
420	struct drr_sched *q = qdisc_priv(sch);
421	int err;
422
423	err = qdisc_class_hash_init(&q->clhash);
424	if (err < 0)
425	return err;
426	INIT_LIST_HEAD(&q->active);
427	return 0;
428	}
429
430	static void drr_reset_qdisc(struct Qdisc *sch)
431	{
432	struct drr_sched *q = qdisc_priv(sch);
433	struct drr_class *cl;
434	struct hlist_node *n;
435	unsigned int i;
436
437	for (i = 0; i < q->clhash.hashsize; i++) {
438	hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
439	if (cl->qdisc->q.qlen)
440	list_del(&cl->alist);
441	qdisc_reset(cl->qdisc);
442	}
443	}
444	sch->q.qlen = 0;
445	}
446
447	static void drr_destroy_qdisc(struct Qdisc *sch)
448	{
449	struct drr_sched *q = qdisc_priv(sch);
450	struct drr_class *cl;
451	struct hlist_node n, next;
452	unsigned int i;
453
454	tcf_destroy_chain(&q->filter_list);
455
456	for (i = 0; i < q->clhash.hashsize; i++) {
457	hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
458	common.hnode)
459	drr_destroy_class(sch, cl);
460	}
461	qdisc_class_hash_destroy(&q->clhash);
462	}
463
464	static const struct Qdisc_class_ops drr_class_ops = {
465	.change = drr_change_class,
466	.delete = drr_delete_class,
467	.get = drr_get_class,
468	.put = drr_put_class,
469	.tcf_chain = drr_tcf_chain,
470	.bind_tcf = drr_bind_tcf,
471	.unbind_tcf = drr_unbind_tcf,
472	.graft = drr_graft_class,
473	.leaf = drr_class_leaf,
474	.qlen_notify = drr_qlen_notify,
475	.dump = drr_dump_class,
476	.dump_stats = drr_dump_class_stats,
477	.walk = drr_walk,
478	};
479
480	static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
481	.cl_ops = &drr_class_ops,
482	.id = "drr",
483	.priv_size = sizeof(struct drr_sched),
484	.enqueue = drr_enqueue,
485	.dequeue = drr_dequeue,
486	.peek = qdisc_peek_dequeued,
487	.drop = drr_drop,
488	.init = drr_init_qdisc,
489	.reset = drr_reset_qdisc,
490	.destroy = drr_destroy_qdisc,
491	.owner = THIS_MODULE,
492	};
493
494	static int __init drr_init(void)
495	{
496	return register_qdisc(&drr_qdisc_ops);
497	}
498
499	static void __exit drr_exit(void)
500	{
501	unregister_qdisc(&drr_qdisc_ops);
502	}
503
504	module_init(drr_init);
505	module_exit(drr_exit);
506	MODULE_LICENSE("GPL");