[mirror_ubuntu-artful-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/slab.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_packed		bstats;
	struct gnet_stats_queue		qstats;
	struct net_rate_estimator __rcu *rate_est;
	struct list_head		alist;
	struct Qdisc			*qdisc;

	u32				quantum;
	u32				deficit;
};

struct drr_sched {
	struct list_head		active;
	struct tcf_proto __rcu		*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;
	unsigned int backlog = cl->qdisc->qstats.backlog;

	qdisc_reset(cl->qdisc);
	qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
}

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 *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_DRR_MAX + 1];
	u32 quantum;
	int err;

	if (!opt)
		return -EINVAL;

	err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, NULL);
	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) {
		if (tca[TCA_RATE]) {
			err = gen_replace_estimator(&cl->bstats, NULL,
						    &cl->rate_est,
						    NULL,
						    qdisc_root_sleeping_running(sch),
						    tca[TCA_RATE]);
			if (err)
				return err;
		}

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

		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(sch->dev_queue,
					       &pfifo_qdisc_ops, classid);
	if (cl->qdisc == NULL)
		cl->qdisc = &noop_qdisc;
	else
		qdisc_hash_add(cl->qdisc, true);

	if (tca[TCA_RATE]) {
		err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est,
					    NULL,
					    qdisc_root_sleeping_running(sch),
					    tca[TCA_RATE]);
		if (err) {
			qdisc_destroy(cl->qdisc);
			kfree(cl);
			return err;
		}
	}

	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->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);

	BUG_ON(--cl->refcnt == 0);
	/*
	 * This shouldn't happen: we "hold" one cops->get() when called
	 * from tc_ctl_tclass; the destroy method is done from cops->put().
	 */

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

	*old = qdisc_replace(sch, new, &cl->qdisc);
	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;
	if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum))
		goto nla_put_failure;
	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;
	__u32 qlen = cl->qdisc->q.qlen;
	struct tc_drr_stats xstats;

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

	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
				  d, NULL, &cl->bstats) < 0 ||
	    gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
	    gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 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;
	unsigned int i;

	if (arg->stop)
		return;

	for (i = 0; i < q->clhash.hashsize; i++) {
		hlist_for_each_entry(cl, &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;
	struct tcf_proto *fl;
	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;
	fl = rcu_dereference_bh(q->filter_list);
	result = tcf_classify(skb, fl, &res, false);
	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 sk_buff **to_free)
{
	struct drr_sched *q = qdisc_priv(sch);
	struct drr_class *cl;
	int err = 0;

	cl = drr_classify(skb, sch, &err);
	if (cl == NULL) {
		if (err & __NET_XMIT_BYPASS)
			qdisc_qstats_drop(sch);
		__qdisc_drop(skb, to_free);
		return err;
	}

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

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

	qdisc_qstats_backlog_inc(sch, skb);
	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;

	if (list_empty(&q->active))
		goto out;
	while (1) {
		cl = list_first_entry(&q->active, struct drr_class, alist);
		skb = cl->qdisc->ops->peek(cl->qdisc);
		if (skb == NULL) {
			qdisc_warn_nonwc(__func__, cl->qdisc);
			goto out;
		}

		len = qdisc_pkt_len(skb);
		if (len <= cl->deficit) {
			cl->deficit -= len;
			skb = qdisc_dequeue_peeked(cl->qdisc);
			if (unlikely(skb == NULL))
				goto out;
			if (cl->qdisc->q.qlen == 0)
				list_del(&cl->alist);

			bstats_update(&cl->bstats, skb);
			qdisc_bstats_update(sch, skb);
			qdisc_qstats_backlog_dec(sch, skb);
			sch->q.qlen--;
			return skb;
		}

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

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;
	unsigned int i;

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

	tcf_destroy_chain(&q->filter_list);

	for (i = 0; i < q->clhash.hashsize; i++) {
		hlist_for_each_entry_safe(cl, 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,
	.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>
5a0e3ad6	12	#include <linux/slab.h>
13d2a1d2 PM	13	#include <linux/init.h>
	14	#include <linux/errno.h>
	15	#include <linux/netdevice.h>
	16	#include <linux/pkt_sched.h>
	17	#include <net/sch_generic.h>
	18	#include <net/pkt_sched.h>
	19	#include <net/pkt_cls.h>
	20
	21	struct drr_class {
	22	struct Qdisc_class_common common;
	23	unsigned int refcnt;
	24	unsigned int filter_cnt;
	25
c1a8f1f1	26	struct gnet_stats_basic_packed bstats;
13d2a1d2	27	struct gnet_stats_queue qstats;
1c0d32fd	28	struct net_rate_estimator __rcu *rate_est;
13d2a1d2 PM	29	struct list_head alist;
	30	struct Qdisc *qdisc;
	31
	32	u32 quantum;
	33	u32 deficit;
	34	};
	35
	36	struct drr_sched {
	37	struct list_head active;
25d8c0d5	38	struct tcf_proto __rcu *filter_list;
13d2a1d2 PM	39	struct Qdisc_class_hash clhash;
	40	};
	41
	42	static struct drr_class drr_find_class(struct Qdisc sch, u32 classid)
	43	{
	44	struct drr_sched *q = qdisc_priv(sch);
	45	struct Qdisc_class_common *clc;
	46
	47	clc = qdisc_class_find(&q->clhash, classid);
	48	if (clc == NULL)
	49	return NULL;
	50	return container_of(clc, struct drr_class, common);
	51	}
	52
	53	static void drr_purge_queue(struct drr_class *cl)
	54	{
	55	unsigned int len = cl->qdisc->q.qlen;
2ccccf5f	56	unsigned int backlog = cl->qdisc->qstats.backlog;
13d2a1d2 PM	57
13d2a1d2 PM	58	qdisc_reset(cl->qdisc);
2ccccf5f	59	qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
13d2a1d2 PM	60	}
	61
	62	static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
	63	[TCA_DRR_QUANTUM] = { .type = NLA_U32 },
	64	};
	65
	66	static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
	67	struct nlattr *tca, unsigned long arg)
	68	{
	69	struct drr_sched *q = qdisc_priv(sch);
	70	struct drr_class cl = (struct drr_class )*arg;
1844f747	71	struct nlattr *opt = tca[TCA_OPTIONS];
13d2a1d2 PM	72	struct nlattr *tb[TCA_DRR_MAX + 1];
	73	u32 quantum;
	74	int err;
	75
1844f747 JP	76	if (!opt)
	77	return -EINVAL;
	78
fceb6435	79	err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy, NULL);
13d2a1d2 PM	80	if (err < 0)
	81	return err;
	82
	83	if (tb[TCA_DRR_QUANTUM]) {
	84	quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
	85	if (quantum == 0)
	86	return -EINVAL;
	87	} else
	88	quantum = psched_mtu(qdisc_dev(sch));
	89
	90	if (cl != NULL) {
71bcb09a	91	if (tca[TCA_RATE]) {
22e0f8b9 JF	92	err = gen_replace_estimator(&cl->bstats, NULL,
22e0f8b9 JF	93	&cl->rate_est,
edb09eb1 ED	94	NULL,
edb09eb1 ED	95	qdisc_root_sleeping_running(sch),
71bcb09a SH	96	tca[TCA_RATE]);
	97	if (err)
	98	return err;
	99	}
	100
13d2a1d2 PM	101	sch_tree_lock(sch);
	102	if (tb[TCA_DRR_QUANTUM])
	103	cl->quantum = quantum;
	104	sch_tree_unlock(sch);
	105
13d2a1d2 PM	106	return 0;
	107	}
	108
	109	cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
	110	if (cl == NULL)
	111	return -ENOBUFS;
	112
	113	cl->refcnt = 1;
	114	cl->common.classid = classid;
	115	cl->quantum = quantum;
3511c913	116	cl->qdisc = qdisc_create_dflt(sch->dev_queue,
13d2a1d2 PM	117	&pfifo_qdisc_ops, classid);
	118	if (cl->qdisc == NULL)
	119	cl->qdisc = &noop_qdisc;
49b49971 JK	120	else
49b49971 JK	121	qdisc_hash_add(cl->qdisc, true);
13d2a1d2	122
71bcb09a	123	if (tca[TCA_RATE]) {
22e0f8b9	124	err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est,
edb09eb1 ED	125	NULL,
edb09eb1 ED	126	qdisc_root_sleeping_running(sch),
71bcb09a SH	127	tca[TCA_RATE]);
	128	if (err) {
	129	qdisc_destroy(cl->qdisc);
	130	kfree(cl);
	131	return err;
	132	}
	133	}
13d2a1d2 PM	134
	135	sch_tree_lock(sch);
	136	qdisc_class_hash_insert(&q->clhash, &cl->common);
	137	sch_tree_unlock(sch);
	138
	139	qdisc_class_hash_grow(sch, &q->clhash);
	140
	141	*arg = (unsigned long)cl;
	142	return 0;
	143	}
	144
	145	static void drr_destroy_class(struct Qdisc sch, struct drr_class cl)
	146	{
1c0d32fd	147	gen_kill_estimator(&cl->rate_est);
13d2a1d2 PM	148	qdisc_destroy(cl->qdisc);
	149	kfree(cl);
	150	}
	151
	152	static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
	153	{
	154	struct drr_sched *q = qdisc_priv(sch);
	155	struct drr_class cl = (struct drr_class )arg;
	156
	157	if (cl->filter_cnt > 0)
	158	return -EBUSY;
	159
	160	sch_tree_lock(sch);
	161
	162	drr_purge_queue(cl);
	163	qdisc_class_hash_remove(&q->clhash, &cl->common);
	164
7cd0a638 JP	165	BUG_ON(--cl->refcnt == 0);
	166	/*
	167	* This shouldn't happen: we "hold" one cops->get() when called
	168	* from tc_ctl_tclass; the destroy method is done from cops->put().
	169	*/
13d2a1d2 PM	170
	171	sch_tree_unlock(sch);
	172	return 0;
	173	}
	174
	175	static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
	176	{
	177	struct drr_class *cl = drr_find_class(sch, classid);
	178
	179	if (cl != NULL)
	180	cl->refcnt++;
	181
	182	return (unsigned long)cl;
	183	}
	184
	185	static void drr_put_class(struct Qdisc *sch, unsigned long arg)
	186	{
	187	struct drr_class cl = (struct drr_class )arg;
	188
	189	if (--cl->refcnt == 0)
	190	drr_destroy_class(sch, cl);
	191	}
	192
25d8c0d5 JF	193	static struct tcf_proto __rcu *drr_tcf_chain(struct Qdisc sch,
25d8c0d5 JF	194	unsigned long cl)
13d2a1d2 PM	195	{
	196	struct drr_sched *q = qdisc_priv(sch);
	197
	198	if (cl)
	199	return NULL;
	200
	201	return &q->filter_list;
	202	}
	203
	204	static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
	205	u32 classid)
	206	{
	207	struct drr_class *cl = drr_find_class(sch, classid);
	208
	209	if (cl != NULL)
	210	cl->filter_cnt++;
	211
	212	return (unsigned long)cl;
	213	}
	214
	215	static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
	216	{
	217	struct drr_class cl = (struct drr_class )arg;
	218
	219	cl->filter_cnt--;
	220	}
	221
	222	static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
	223	struct Qdisc new, struct Qdisc *old)
	224	{
	225	struct drr_class cl = (struct drr_class )arg;
	226
	227	if (new == NULL) {
3511c913	228	new = qdisc_create_dflt(sch->dev_queue,
13d2a1d2 PM	229	&pfifo_qdisc_ops, cl->common.classid);
	230	if (new == NULL)
	231	new = &noop_qdisc;
	232	}
	233
86a7996c	234	*old = qdisc_replace(sch, new, &cl->qdisc);
13d2a1d2 PM	235	return 0;
	236	}
	237
	238	static struct Qdisc drr_class_leaf(struct Qdisc sch, unsigned long arg)
	239	{
	240	struct drr_class cl = (struct drr_class )arg;
	241
	242	return cl->qdisc;
	243	}
	244
	245	static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
	246	{
	247	struct drr_class cl = (struct drr_class )arg;
	248
	249	if (cl->qdisc->q.qlen == 0)
	250	list_del(&cl->alist);
	251	}
	252
	253	static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
	254	struct sk_buff skb, struct tcmsg tcm)
	255	{
	256	struct drr_class cl = (struct drr_class )arg;
	257	struct nlattr *nest;
	258
	259	tcm->tcm_parent = TC_H_ROOT;
	260	tcm->tcm_handle = cl->common.classid;
	261	tcm->tcm_info = cl->qdisc->handle;
	262
	263	nest = nla_nest_start(skb, TCA_OPTIONS);
	264	if (nest == NULL)
	265	goto nla_put_failure;
1b34ec43 DM	266	if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum))
1b34ec43 DM	267	goto nla_put_failure;
13d2a1d2 PM	268	return nla_nest_end(skb, nest);
	269
	270	nla_put_failure:
	271	nla_nest_cancel(skb, nest);
	272	return -EMSGSIZE;
	273	}
	274
	275	static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
	276	struct gnet_dump *d)
	277	{
	278	struct drr_class cl = (struct drr_class )arg;
64015853	279	__u32 qlen = cl->qdisc->q.qlen;
13d2a1d2 PM	280	struct tc_drr_stats xstats;
	281
	282	memset(&xstats, 0, sizeof(xstats));
64015853	283	if (qlen)
13d2a1d2 PM	284	xstats.deficit = cl->deficit;
13d2a1d2 PM	285
edb09eb1 ED	286	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
edb09eb1 ED	287	d, NULL, &cl->bstats) < 0 \|\|
1c0d32fd	288	gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 \|\|
b0ab6f92	289	gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 0)
13d2a1d2 PM	290	return -1;
	291
	292	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
	293	}
	294
	295	static void drr_walk(struct Qdisc sch, struct qdisc_walker arg)
	296	{
	297	struct drr_sched *q = qdisc_priv(sch);
	298	struct drr_class *cl;
13d2a1d2 PM	299	unsigned int i;
	300
	301	if (arg->stop)
	302	return;
	303
	304	for (i = 0; i < q->clhash.hashsize; i++) {
b67bfe0d	305	hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
13d2a1d2 PM	306	if (arg->count < arg->skip) {
	307	arg->count++;
	308	continue;
	309	}
	310	if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
	311	arg->stop = 1;
	312	return;
	313	}
	314	arg->count++;
	315	}
	316	}
	317	}
	318
	319	static struct drr_class drr_classify(struct sk_buff skb, struct Qdisc *sch,
	320	int *qerr)
	321	{
	322	struct drr_sched *q = qdisc_priv(sch);
	323	struct drr_class *cl;
	324	struct tcf_result res;
25d8c0d5	325	struct tcf_proto *fl;
13d2a1d2 PM	326	int result;
	327
	328	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
	329	cl = drr_find_class(sch, skb->priority);
	330	if (cl != NULL)
	331	return cl;
	332	}
	333
	334	*qerr = NET_XMIT_SUCCESS \| __NET_XMIT_BYPASS;
25d8c0d5	335	fl = rcu_dereference_bh(q->filter_list);
87d83093	336	result = tcf_classify(skb, fl, &res, false);
13d2a1d2 PM	337	if (result >= 0) {
	338	#ifdef CONFIG_NET_CLS_ACT
	339	switch (result) {
	340	case TC_ACT_QUEUED:
	341	case TC_ACT_STOLEN:
	342	*qerr = NET_XMIT_SUCCESS \| __NET_XMIT_STOLEN;
	343	case TC_ACT_SHOT:
	344	return NULL;
	345	}
	346	#endif
	347	cl = (struct drr_class *)res.class;
	348	if (cl == NULL)
	349	cl = drr_find_class(sch, res.classid);
	350	return cl;
	351	}
	352	return NULL;
	353	}
	354
520ac30f ED	355	static int drr_enqueue(struct sk_buff skb, struct Qdisc sch,
520ac30f ED	356	struct sk_buff **to_free)
13d2a1d2 PM	357	{
	358	struct drr_sched *q = qdisc_priv(sch);
	359	struct drr_class *cl;
f54ba779	360	int err = 0;
13d2a1d2 PM	361
	362	cl = drr_classify(skb, sch, &err);
	363	if (cl == NULL) {
	364	if (err & __NET_XMIT_BYPASS)
25331d6c	365	qdisc_qstats_drop(sch);
520ac30f	366	__qdisc_drop(skb, to_free);
13d2a1d2 PM	367	return err;
	368	}
	369
520ac30f	370	err = qdisc_enqueue(skb, cl->qdisc, to_free);
13d2a1d2 PM	371	if (unlikely(err != NET_XMIT_SUCCESS)) {
	372	if (net_xmit_drop_count(err)) {
	373	cl->qstats.drops++;
25331d6c	374	qdisc_qstats_drop(sch);
13d2a1d2 PM	375	}
	376	return err;
	377	}
	378
	379	if (cl->qdisc->q.qlen == 1) {
	380	list_add_tail(&cl->alist, &q->active);
	381	cl->deficit = cl->quantum;
	382	}
	383
6a73b571	384	qdisc_qstats_backlog_inc(sch, skb);
13d2a1d2 PM	385	sch->q.qlen++;
	386	return err;
	387	}
	388
	389	static struct sk_buff drr_dequeue(struct Qdisc sch)
	390	{
	391	struct drr_sched *q = qdisc_priv(sch);
	392	struct drr_class *cl;
	393	struct sk_buff *skb;
	394	unsigned int len;
	395
3f0947c3 PM	396	if (list_empty(&q->active))
	397	goto out;
	398	while (1) {
13d2a1d2 PM	399	cl = list_first_entry(&q->active, struct drr_class, alist);
13d2a1d2 PM	400	skb = cl->qdisc->ops->peek(cl->qdisc);
6e765a00 FW	401	if (skb == NULL) {
6e765a00 FW	402	qdisc_warn_nonwc(__func__, cl->qdisc);
3f0947c3	403	goto out;
6e765a00	404	}
13d2a1d2 PM	405
	406	len = qdisc_pkt_len(skb);
	407	if (len <= cl->deficit) {
	408	cl->deficit -= len;
	409	skb = qdisc_dequeue_peeked(cl->qdisc);
df3eb6cd BH	410	if (unlikely(skb == NULL))
df3eb6cd BH	411	goto out;
13d2a1d2 PM	412	if (cl->qdisc->q.qlen == 0)
13d2a1d2 PM	413	list_del(&cl->alist);
2dd875ff ED	414
2dd875ff ED	415	bstats_update(&cl->bstats, skb);
9190b3b3	416	qdisc_bstats_update(sch, skb);
6a73b571	417	qdisc_qstats_backlog_dec(sch, skb);
13d2a1d2 PM	418	sch->q.qlen--;
	419	return skb;
	420	}
	421
	422	cl->deficit += cl->quantum;
13d2a1d2 PM	423	list_move_tail(&cl->alist, &q->active);
13d2a1d2 PM	424	}
3f0947c3	425	out:
13d2a1d2 PM	426	return NULL;
	427	}
	428
13d2a1d2 PM	429	static int drr_init_qdisc(struct Qdisc sch, struct nlattr opt)
	430	{
	431	struct drr_sched *q = qdisc_priv(sch);
	432	int err;
	433
	434	err = qdisc_class_hash_init(&q->clhash);
	435	if (err < 0)
	436	return err;
	437	INIT_LIST_HEAD(&q->active);
	438	return 0;
	439	}
	440
	441	static void drr_reset_qdisc(struct Qdisc *sch)
	442	{
	443	struct drr_sched *q = qdisc_priv(sch);
	444	struct drr_class *cl;
13d2a1d2 PM	445	unsigned int i;
	446
	447	for (i = 0; i < q->clhash.hashsize; i++) {
b67bfe0d	448	hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
13d2a1d2 PM	449	if (cl->qdisc->q.qlen)
	450	list_del(&cl->alist);
	451	qdisc_reset(cl->qdisc);
	452	}
	453	}
6a73b571	454	sch->qstats.backlog = 0;
13d2a1d2 PM	455	sch->q.qlen = 0;
	456	}
	457
	458	static void drr_destroy_qdisc(struct Qdisc *sch)
	459	{
	460	struct drr_sched *q = qdisc_priv(sch);
	461	struct drr_class *cl;
b67bfe0d	462	struct hlist_node *next;
13d2a1d2 PM	463	unsigned int i;
	464
	465	tcf_destroy_chain(&q->filter_list);
	466
	467	for (i = 0; i < q->clhash.hashsize; i++) {
b67bfe0d	468	hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
13d2a1d2 PM	469	common.hnode)
	470	drr_destroy_class(sch, cl);
	471	}
	472	qdisc_class_hash_destroy(&q->clhash);
	473	}
	474
	475	static const struct Qdisc_class_ops drr_class_ops = {
	476	.change = drr_change_class,
	477	.delete = drr_delete_class,
	478	.get = drr_get_class,
	479	.put = drr_put_class,
	480	.tcf_chain = drr_tcf_chain,
	481	.bind_tcf = drr_bind_tcf,
	482	.unbind_tcf = drr_unbind_tcf,
	483	.graft = drr_graft_class,
	484	.leaf = drr_class_leaf,
	485	.qlen_notify = drr_qlen_notify,
	486	.dump = drr_dump_class,
	487	.dump_stats = drr_dump_class_stats,
	488	.walk = drr_walk,
	489	};
	490
	491	static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
	492	.cl_ops = &drr_class_ops,
	493	.id = "drr",
	494	.priv_size = sizeof(struct drr_sched),
	495	.enqueue = drr_enqueue,
	496	.dequeue = drr_dequeue,
	497	.peek = qdisc_peek_dequeued,
13d2a1d2 PM	498	.init = drr_init_qdisc,
	499	.reset = drr_reset_qdisc,
	500	.destroy = drr_destroy_qdisc,
	501	.owner = THIS_MODULE,
	502	};
	503
	504	static int __init drr_init(void)
	505	{
	506	return register_qdisc(&drr_qdisc_ops);
	507	}
	508
	509	static void __exit drr_exit(void)
	510	{
	511	unregister_qdisc(&drr_qdisc_ops);
	512	}
	513
	514	module_init(drr_init);
	515	module_exit(drr_exit);
	516	MODULE_LICENSE("GPL");