[mirror_ubuntu-bionic-kernel.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 = xchg(&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);
211	*old = xchg(&cl->qdisc, new);
212	sch_tree_unlock(sch);
213	return 0;
214	}
215
216	static struct Qdisc drr_class_leaf(struct Qdisc sch, unsigned long arg)
217	{
218	struct drr_class cl = (struct drr_class )arg;
219
220	return cl->qdisc;
221	}
222
223	static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
224	{
225	struct drr_class cl = (struct drr_class )arg;
226
227	if (cl->qdisc->q.qlen == 0)
228	list_del(&cl->alist);
229	}
230
231	static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
232	struct sk_buff skb, struct tcmsg tcm)
233	{
234	struct drr_class cl = (struct drr_class )arg;
235	struct nlattr *nest;
236
237	tcm->tcm_parent = TC_H_ROOT;
238	tcm->tcm_handle = cl->common.classid;
239	tcm->tcm_info = cl->qdisc->handle;
240
241	nest = nla_nest_start(skb, TCA_OPTIONS);
242	if (nest == NULL)
243	goto nla_put_failure;
244	NLA_PUT_U32(skb, TCA_DRR_QUANTUM, cl->quantum);
245	return nla_nest_end(skb, nest);
246
247	nla_put_failure:
248	nla_nest_cancel(skb, nest);
249	return -EMSGSIZE;
250	}
251
252	static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
253	struct gnet_dump *d)
254	{
255	struct drr_class cl = (struct drr_class )arg;
256	struct tc_drr_stats xstats;
257
258	memset(&xstats, 0, sizeof(xstats));
259	if (cl->qdisc->q.qlen)
260	xstats.deficit = cl->deficit;
261
262	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 \|\|
263	gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 \|\|
264	gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 0)
265	return -1;
266
267	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
268	}
269
270	static void drr_walk(struct Qdisc sch, struct qdisc_walker arg)
271	{
272	struct drr_sched *q = qdisc_priv(sch);
273	struct drr_class *cl;
274	struct hlist_node *n;
275	unsigned int i;
276
277	if (arg->stop)
278	return;
279
280	for (i = 0; i < q->clhash.hashsize; i++) {
281	hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
282	if (arg->count < arg->skip) {
283	arg->count++;
284	continue;
285	}
286	if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
287	arg->stop = 1;
288	return;
289	}
290	arg->count++;
291	}
292	}
293	}
294
295	static struct drr_class drr_classify(struct sk_buff skb, struct Qdisc *sch,
296	int *qerr)
297	{
298	struct drr_sched *q = qdisc_priv(sch);
299	struct drr_class *cl;
300	struct tcf_result res;
301	int result;
302
303	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
304	cl = drr_find_class(sch, skb->priority);
305	if (cl != NULL)
306	return cl;
307	}
308
309	*qerr = NET_XMIT_SUCCESS \| __NET_XMIT_BYPASS;
310	result = tc_classify(skb, q->filter_list, &res);
311	if (result >= 0) {
312	#ifdef CONFIG_NET_CLS_ACT
313	switch (result) {
314	case TC_ACT_QUEUED:
315	case TC_ACT_STOLEN:
316	*qerr = NET_XMIT_SUCCESS \| __NET_XMIT_STOLEN;
317	case TC_ACT_SHOT:
318	return NULL;
319	}
320	#endif
321	cl = (struct drr_class *)res.class;
322	if (cl == NULL)
323	cl = drr_find_class(sch, res.classid);
324	return cl;
325	}
326	return NULL;
327	}
328
329	static int drr_enqueue(struct sk_buff skb, struct Qdisc sch)
330	{
331	struct drr_sched *q = qdisc_priv(sch);
332	struct drr_class *cl;
333	unsigned int len;
334	int err;
335
336	cl = drr_classify(skb, sch, &err);
337	if (cl == NULL) {
338	if (err & __NET_XMIT_BYPASS)
339	sch->qstats.drops++;
340	kfree_skb(skb);
341	return err;
342	}
343
344	len = qdisc_pkt_len(skb);
345	err = qdisc_enqueue(skb, cl->qdisc);
346	if (unlikely(err != NET_XMIT_SUCCESS)) {
347	if (net_xmit_drop_count(err)) {
348	cl->qstats.drops++;
349	sch->qstats.drops++;
350	}
351	return err;
352	}
353
354	if (cl->qdisc->q.qlen == 1) {
355	list_add_tail(&cl->alist, &q->active);
356	cl->deficit = cl->quantum;
357	}
358
359	cl->bstats.packets++;
360	cl->bstats.bytes += len;
361	sch->bstats.packets++;
362	sch->bstats.bytes += len;
363
364	sch->q.qlen++;
365	return err;
366	}
367
368	static struct sk_buff drr_dequeue(struct Qdisc sch)
369	{
370	struct drr_sched *q = qdisc_priv(sch);
371	struct drr_class *cl;
372	struct sk_buff *skb;
373	unsigned int len;
374
375	while (!list_empty(&q->active)) {
376	cl = list_first_entry(&q->active, struct drr_class, alist);
377	skb = cl->qdisc->ops->peek(cl->qdisc);
378	if (skb == NULL)
379	goto skip;
380
381	len = qdisc_pkt_len(skb);
382	if (len <= cl->deficit) {
383	cl->deficit -= len;
384	skb = qdisc_dequeue_peeked(cl->qdisc);
385	if (cl->qdisc->q.qlen == 0)
386	list_del(&cl->alist);
387	sch->q.qlen--;
388	return skb;
389	}
390
391	cl->deficit += cl->quantum;
392	skip:
393	list_move_tail(&cl->alist, &q->active);
394	}
395	return NULL;
396	}
397
398	static unsigned int drr_drop(struct Qdisc *sch)
399	{
400	struct drr_sched *q = qdisc_priv(sch);
401	struct drr_class *cl;
402	unsigned int len;
403
404	list_for_each_entry(cl, &q->active, alist) {
405	if (cl->qdisc->ops->drop) {
406	len = cl->qdisc->ops->drop(cl->qdisc);
407	if (len > 0) {
408	if (cl->qdisc->q.qlen == 0)
409	list_del(&cl->alist);
410	return len;
411	}
412	}
413	}
414	return 0;
415	}
416
417	static int drr_init_qdisc(struct Qdisc sch, struct nlattr opt)
418	{
419	struct drr_sched *q = qdisc_priv(sch);
420	int err;
421
422	err = qdisc_class_hash_init(&q->clhash);
423	if (err < 0)
424	return err;
425	INIT_LIST_HEAD(&q->active);
426	return 0;
427	}
428
429	static void drr_reset_qdisc(struct Qdisc *sch)
430	{
431	struct drr_sched *q = qdisc_priv(sch);
432	struct drr_class *cl;
433	struct hlist_node *n;
434	unsigned int i;
435
436	for (i = 0; i < q->clhash.hashsize; i++) {
437	hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
438	if (cl->qdisc->q.qlen)
439	list_del(&cl->alist);
440	qdisc_reset(cl->qdisc);
441	}
442	}
443	sch->q.qlen = 0;
444	}
445
446	static void drr_destroy_qdisc(struct Qdisc *sch)
447	{
448	struct drr_sched *q = qdisc_priv(sch);
449	struct drr_class *cl;
450	struct hlist_node n, next;
451	unsigned int i;
452
453	tcf_destroy_chain(&q->filter_list);
454
455	for (i = 0; i < q->clhash.hashsize; i++) {
456	hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
457	common.hnode)
458	drr_destroy_class(sch, cl);
459	}
460	qdisc_class_hash_destroy(&q->clhash);
461	}
462
463	static const struct Qdisc_class_ops drr_class_ops = {
464	.change = drr_change_class,
465	.delete = drr_delete_class,
466	.get = drr_get_class,
467	.put = drr_put_class,
468	.tcf_chain = drr_tcf_chain,
469	.bind_tcf = drr_bind_tcf,
470	.unbind_tcf = drr_unbind_tcf,
471	.graft = drr_graft_class,
472	.leaf = drr_class_leaf,
473	.qlen_notify = drr_qlen_notify,
474	.dump = drr_dump_class,
475	.dump_stats = drr_dump_class_stats,
476	.walk = drr_walk,
477	};
478
479	static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
480	.cl_ops = &drr_class_ops,
481	.id = "drr",
482	.priv_size = sizeof(struct drr_sched),
483	.enqueue = drr_enqueue,
484	.dequeue = drr_dequeue,
485	.peek = qdisc_peek_dequeued,
486	.drop = drr_drop,
487	.init = drr_init_qdisc,
488	.reset = drr_reset_qdisc,
489	.destroy = drr_destroy_qdisc,
490	.owner = THIS_MODULE,
491	};
492
493	static int __init drr_init(void)
494	{
495	return register_qdisc(&drr_qdisc_ops);
496	}
497
498	static void __exit drr_exit(void)
499	{
500	unregister_qdisc(&drr_qdisc_ops);
501	}
502
503	module_init(drr_init);
504	module_exit(drr_exit);
505	MODULE_LICENSE("GPL");