[mirror_ubuntu-bionic-kernel.git] / net / sched / sch_red.c

/*
 * net/sched/sch_red.c	Random Early Detection queue.
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 * Changes:
 * J Hadi Salim 980914:	computation fixes
 * Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
 * J Hadi Salim 980816:  ECN support
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <net/inet_ecn.h>
#include <net/red.h>


/*	Parameters, settable by user:
	-----------------------------

	limit		- bytes (must be > qth_max + burst)

	Hard limit on queue length, should be chosen >qth_max
	to allow packet bursts. This parameter does not
	affect the algorithms behaviour and can be chosen
	arbitrarily high (well, less than ram size)
	Really, this limit will never be reached
	if RED works correctly.
 */

struct red_sched_data {
	u32			limit;		/* HARD maximal queue length */
	unsigned char		flags;
	struct timer_list	adapt_timer;
	struct Qdisc		*sch;
	struct red_parms	parms;
	struct red_vars		vars;
	struct red_stats	stats;
	struct Qdisc		*qdisc;
};

static inline int red_use_ecn(struct red_sched_data *q)
{
	return q->flags & TC_RED_ECN;
}

static inline int red_use_harddrop(struct red_sched_data *q)
{
	return q->flags & TC_RED_HARDDROP;
}

static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
		       struct sk_buff **to_free)
{
	struct red_sched_data *q = qdisc_priv(sch);
	struct Qdisc *child = q->qdisc;
	int ret;

	q->vars.qavg = red_calc_qavg(&q->parms,
				     &q->vars,
				     child->qstats.backlog);

	if (red_is_idling(&q->vars))
		red_end_of_idle_period(&q->vars);

	switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
	case RED_DONT_MARK:
		break;

	case RED_PROB_MARK:
		qdisc_qstats_overlimit(sch);
		if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
			q->stats.prob_drop++;
			goto congestion_drop;
		}

		q->stats.prob_mark++;
		break;

	case RED_HARD_MARK:
		qdisc_qstats_overlimit(sch);
		if (red_use_harddrop(q) || !red_use_ecn(q) ||
		    !INET_ECN_set_ce(skb)) {
			q->stats.forced_drop++;
			goto congestion_drop;
		}

		q->stats.forced_mark++;
		break;
	}

	ret = qdisc_enqueue(skb, child, to_free);
	if (likely(ret == NET_XMIT_SUCCESS)) {
		qdisc_qstats_backlog_inc(sch, skb);
		sch->q.qlen++;
	} else if (net_xmit_drop_count(ret)) {
		q->stats.pdrop++;
		qdisc_qstats_drop(sch);
	}
	return ret;

congestion_drop:
	qdisc_drop(skb, sch, to_free);
	return NET_XMIT_CN;
}

static struct sk_buff *red_dequeue(struct Qdisc *sch)
{
	struct sk_buff *skb;
	struct red_sched_data *q = qdisc_priv(sch);
	struct Qdisc *child = q->qdisc;

	skb = child->dequeue(child);
	if (skb) {
		qdisc_bstats_update(sch, skb);
		qdisc_qstats_backlog_dec(sch, skb);
		sch->q.qlen--;
	} else {
		if (!red_is_idling(&q->vars))
			red_start_of_idle_period(&q->vars);
	}
	return skb;
}

static struct sk_buff *red_peek(struct Qdisc *sch)
{
	struct red_sched_data *q = qdisc_priv(sch);
	struct Qdisc *child = q->qdisc;

	return child->ops->peek(child);
}

static void red_reset(struct Qdisc *sch)
{
	struct red_sched_data *q = qdisc_priv(sch);

	qdisc_reset(q->qdisc);
	sch->qstats.backlog = 0;
	sch->q.qlen = 0;
	red_restart(&q->vars);
}

static int red_offload(struct Qdisc *sch, bool enable)
{
	struct red_sched_data *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct tc_red_qopt_offload opt = {
		.handle = sch->handle,
		.parent = sch->parent,
	};

	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
		return -EOPNOTSUPP;

	if (enable) {
		opt.command = TC_RED_REPLACE;
		opt.set.min = q->parms.qth_min >> q->parms.Wlog;
		opt.set.max = q->parms.qth_max >> q->parms.Wlog;
		opt.set.probability = q->parms.max_P;
		opt.set.is_ecn = red_use_ecn(q);
	} else {
		opt.command = TC_RED_DESTROY;
	}

	return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
}

static void red_destroy(struct Qdisc *sch)
{
	struct red_sched_data *q = qdisc_priv(sch);

	del_timer_sync(&q->adapt_timer);
	red_offload(sch, false);
	qdisc_destroy(q->qdisc);
}

static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
	[TCA_RED_PARMS]	= { .len = sizeof(struct tc_red_qopt) },
	[TCA_RED_STAB]	= { .len = RED_STAB_SIZE },
	[TCA_RED_MAX_P] = { .type = NLA_U32 },
};

static int red_change(struct Qdisc *sch, struct nlattr *opt)
{
	struct red_sched_data *q = qdisc_priv(sch);
	struct nlattr *tb[TCA_RED_MAX + 1];
	struct tc_red_qopt *ctl;
	struct Qdisc *child = NULL;
	int err;
	u32 max_P;

	if (opt == NULL)
		return -EINVAL;

	err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy, NULL);
	if (err < 0)
		return err;

	if (tb[TCA_RED_PARMS] == NULL ||
	    tb[TCA_RED_STAB] == NULL)
		return -EINVAL;

	max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;

	ctl = nla_data(tb[TCA_RED_PARMS]);
	if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
		return -EINVAL;

	if (ctl->limit > 0) {
		child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
		if (IS_ERR(child))
			return PTR_ERR(child);

		/* child is fifo, no need to check for noop_qdisc */
		qdisc_hash_add(child, true);
	}

	sch_tree_lock(sch);
	q->flags = ctl->flags;
	q->limit = ctl->limit;
	if (child) {
		qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
					  q->qdisc->qstats.backlog);
		qdisc_destroy(q->qdisc);
		q->qdisc = child;
	}

	red_set_parms(&q->parms,
		      ctl->qth_min, ctl->qth_max, ctl->Wlog,
		      ctl->Plog, ctl->Scell_log,
		      nla_data(tb[TCA_RED_STAB]),
		      max_P);
	red_set_vars(&q->vars);

	del_timer(&q->adapt_timer);
	if (ctl->flags & TC_RED_ADAPTATIVE)
		mod_timer(&q->adapt_timer, jiffies + HZ/2);

	if (!q->qdisc->q.qlen)
		red_start_of_idle_period(&q->vars);

	sch_tree_unlock(sch);
	red_offload(sch, true);
	return 0;
}

static inline void red_adaptative_timer(struct timer_list *t)
{
	struct red_sched_data *q = from_timer(q, t, adapt_timer);
	struct Qdisc *sch = q->sch;
	spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));

	spin_lock(root_lock);
	red_adaptative_algo(&q->parms, &q->vars);
	mod_timer(&q->adapt_timer, jiffies + HZ/2);
	spin_unlock(root_lock);
}

static int red_init(struct Qdisc *sch, struct nlattr *opt)
{
	struct red_sched_data *q = qdisc_priv(sch);

	q->qdisc = &noop_qdisc;
	q->sch = sch;
	timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
	return red_change(sch, opt);
}

static int red_dump_offload_stats(struct Qdisc *sch, struct tc_red_qopt *opt)
{
	struct net_device *dev = qdisc_dev(sch);
	struct tc_red_qopt_offload hw_stats = {
		.command = TC_RED_STATS,
		.handle = sch->handle,
		.parent = sch->parent,
		{
			.stats.bstats = &sch->bstats,
			.stats.qstats = &sch->qstats,
		},
	};
	int err;

	sch->flags &= ~TCQ_F_OFFLOADED;

	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
		return 0;

	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
					    &hw_stats);
	if (err == -EOPNOTSUPP)
		return 0;

	if (!err)
		sch->flags |= TCQ_F_OFFLOADED;

	return err;
}

static int red_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	struct red_sched_data *q = qdisc_priv(sch);
	struct nlattr *opts = NULL;
	struct tc_red_qopt opt = {
		.limit		= q->limit,
		.flags		= q->flags,
		.qth_min	= q->parms.qth_min >> q->parms.Wlog,
		.qth_max	= q->parms.qth_max >> q->parms.Wlog,
		.Wlog		= q->parms.Wlog,
		.Plog		= q->parms.Plog,
		.Scell_log	= q->parms.Scell_log,
	};
	int err;

	sch->qstats.backlog = q->qdisc->qstats.backlog;
	err = red_dump_offload_stats(sch, &opt);
	if (err)
		goto nla_put_failure;

	opts = nla_nest_start(skb, TCA_OPTIONS);
	if (opts == NULL)
		goto nla_put_failure;
	if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) ||
	    nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
		goto nla_put_failure;
	return nla_nest_end(skb, opts);

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

static int red_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
	struct red_sched_data *q = qdisc_priv(sch);
	struct net_device *dev = qdisc_dev(sch);
	struct tc_red_xstats st = {
		.early	= q->stats.prob_drop + q->stats.forced_drop,
		.pdrop	= q->stats.pdrop,
		.other	= q->stats.other,
		.marked	= q->stats.prob_mark + q->stats.forced_mark,
	};

	if (sch->flags & TCQ_F_OFFLOADED) {
		struct red_stats hw_stats = {0};
		struct tc_red_qopt_offload hw_stats_request = {
			.command = TC_RED_XSTATS,
			.handle = sch->handle,
			.parent = sch->parent,
			{
				.xstats = &hw_stats,
			},
		};
		if (!dev->netdev_ops->ndo_setup_tc(dev,
						   TC_SETUP_QDISC_RED,
						   &hw_stats_request)) {
			st.early += hw_stats.prob_drop + hw_stats.forced_drop;
			st.pdrop += hw_stats.pdrop;
			st.other += hw_stats.other;
			st.marked += hw_stats.prob_mark + hw_stats.forced_mark;
		}
	}

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

static int red_dump_class(struct Qdisc *sch, unsigned long cl,
			  struct sk_buff *skb, struct tcmsg *tcm)
{
	struct red_sched_data *q = qdisc_priv(sch);

	tcm->tcm_handle |= TC_H_MIN(1);
	tcm->tcm_info = q->qdisc->handle;
	return 0;
}

static int red_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
		     struct Qdisc **old)
{
	struct red_sched_data *q = qdisc_priv(sch);

	if (new == NULL)
		new = &noop_qdisc;

	*old = qdisc_replace(sch, new, &q->qdisc);
	return 0;
}

static struct Qdisc *red_leaf(struct Qdisc *sch, unsigned long arg)
{
	struct red_sched_data *q = qdisc_priv(sch);
	return q->qdisc;
}

static unsigned long red_find(struct Qdisc *sch, u32 classid)
{
	return 1;
}

static void red_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
	if (!walker->stop) {
		if (walker->count >= walker->skip)
			if (walker->fn(sch, 1, walker) < 0) {
				walker->stop = 1;
				return;
			}
		walker->count++;
	}
}

static const struct Qdisc_class_ops red_class_ops = {
	.graft		=	red_graft,
	.leaf		=	red_leaf,
	.find		=	red_find,
	.walk		=	red_walk,
	.dump		=	red_dump_class,
};

static struct Qdisc_ops red_qdisc_ops __read_mostly = {
	.id		=	"red",
	.priv_size	=	sizeof(struct red_sched_data),
	.cl_ops		=	&red_class_ops,
	.enqueue	=	red_enqueue,
	.dequeue	=	red_dequeue,
	.peek		=	red_peek,
	.init		=	red_init,
	.reset		=	red_reset,
	.destroy	=	red_destroy,
	.change		=	red_change,
	.dump		=	red_dump,
	.dump_stats	=	red_dump_stats,
	.owner		=	THIS_MODULE,
};

static int __init red_module_init(void)
{
	return register_qdisc(&red_qdisc_ops);
}

static void __exit red_module_exit(void)
{
	unregister_qdisc(&red_qdisc_ops);
}

module_init(red_module_init)
module_exit(red_module_exit)

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* net/sched/sch_red.c Random Early Detection queue.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*
	9	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	10	*
	11	* Changes:
dba051f3	12	* J Hadi Salim 980914: computation fixes
1da177e4	13	* Alexey Makarenko <makar@phoenix.kharkov.ua> 990814: qave on idle link was calculated incorrectly.
dba051f3	14	* J Hadi Salim 980816: ECN support
1da177e4 LT	15	*/
1da177e4 LT	16
1da177e4	17	#include <linux/module.h>
1da177e4 LT	18	#include <linux/types.h>
1da177e4 LT	19	#include <linux/kernel.h>
1da177e4	20	#include <linux/skbuff.h>
1da177e4	21	#include <net/pkt_sched.h>
602f3baf	22	#include <net/pkt_cls.h>
1da177e4	23	#include <net/inet_ecn.h>
6b31b28a	24	#include <net/red.h>
1da177e4 LT	25
1da177e4 LT	26
6b31b28a	27	/* Parameters, settable by user:
1da177e4 LT	28	-----------------------------
	29
	30	limit - bytes (must be > qth_max + burst)
	31
	32	Hard limit on queue length, should be chosen >qth_max
	33	to allow packet bursts. This parameter does not
	34	affect the algorithms behaviour and can be chosen
	35	arbitrarily high (well, less than ram size)
	36	Really, this limit will never be reached
	37	if RED works correctly.
1da177e4 LT	38	*/
1da177e4 LT	39
cc7ec456	40	struct red_sched_data {
6b31b28a TG	41	u32 limit; /* HARD maximal queue length */
6b31b28a TG	42	unsigned char flags;
8af2a218	43	struct timer_list adapt_timer;
cdeabbb8	44	struct Qdisc *sch;
6b31b28a	45	struct red_parms parms;
eeca6688	46	struct red_vars vars;
6b31b28a	47	struct red_stats stats;
f38c39d6	48	struct Qdisc *qdisc;
1da177e4 LT	49	};
1da177e4 LT	50
6b31b28a	51	static inline int red_use_ecn(struct red_sched_data *q)
1da177e4	52	{
6b31b28a	53	return q->flags & TC_RED_ECN;
1da177e4 LT	54	}
1da177e4 LT	55
bdc450a0 TG	56	static inline int red_use_harddrop(struct red_sched_data *q)
	57	{
	58	return q->flags & TC_RED_HARDDROP;
	59	}
	60
520ac30f ED	61	static int red_enqueue(struct sk_buff skb, struct Qdisc sch,
520ac30f ED	62	struct sk_buff **to_free)
1da177e4 LT	63	{
1da177e4 LT	64	struct red_sched_data *q = qdisc_priv(sch);
f38c39d6 PM	65	struct Qdisc *child = q->qdisc;
f38c39d6 PM	66	int ret;
1da177e4	67
eeca6688 ED	68	q->vars.qavg = red_calc_qavg(&q->parms,
	69	&q->vars,
	70	child->qstats.backlog);
1da177e4	71
eeca6688 ED	72	if (red_is_idling(&q->vars))
eeca6688 ED	73	red_end_of_idle_period(&q->vars);
1da177e4	74
eeca6688	75	switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
cc7ec456 ED	76	case RED_DONT_MARK:
	77	break;
	78
	79	case RED_PROB_MARK:
25331d6c	80	qdisc_qstats_overlimit(sch);
cc7ec456 ED	81	if (!red_use_ecn(q) \|\| !INET_ECN_set_ce(skb)) {
	82	q->stats.prob_drop++;
	83	goto congestion_drop;
	84	}
	85
	86	q->stats.prob_mark++;
	87	break;
	88
	89	case RED_HARD_MARK:
25331d6c	90	qdisc_qstats_overlimit(sch);
cc7ec456 ED	91	if (red_use_harddrop(q) \|\| !red_use_ecn(q) \|\|
	92	!INET_ECN_set_ce(skb)) {
	93	q->stats.forced_drop++;
	94	goto congestion_drop;
	95	}
	96
	97	q->stats.forced_mark++;
	98	break;
1da177e4 LT	99	}
1da177e4 LT	100
520ac30f	101	ret = qdisc_enqueue(skb, child, to_free);
f38c39d6	102	if (likely(ret == NET_XMIT_SUCCESS)) {
d7f4f332	103	qdisc_qstats_backlog_inc(sch, skb);
f38c39d6	104	sch->q.qlen++;
378a2f09	105	} else if (net_xmit_drop_count(ret)) {
f38c39d6	106	q->stats.pdrop++;
25331d6c	107	qdisc_qstats_drop(sch);
f38c39d6 PM	108	}
f38c39d6 PM	109	return ret;
6b31b28a TG	110
6b31b28a TG	111	congestion_drop:
520ac30f	112	qdisc_drop(skb, sch, to_free);
1da177e4 LT	113	return NET_XMIT_CN;
	114	}
	115
cc7ec456	116	static struct sk_buff red_dequeue(struct Qdisc sch)
1da177e4 LT	117	{
	118	struct sk_buff *skb;
	119	struct red_sched_data *q = qdisc_priv(sch);
f38c39d6	120	struct Qdisc *child = q->qdisc;
1da177e4	121
f38c39d6	122	skb = child->dequeue(child);
9190b3b3 ED	123	if (skb) {
9190b3b3 ED	124	qdisc_bstats_update(sch, skb);
d7f4f332	125	qdisc_qstats_backlog_dec(sch, skb);
f38c39d6	126	sch->q.qlen--;
9190b3b3	127	} else {
eeca6688 ED	128	if (!red_is_idling(&q->vars))
eeca6688 ED	129	red_start_of_idle_period(&q->vars);
9190b3b3	130	}
9e178ff2	131	return skb;
1da177e4 LT	132	}
1da177e4 LT	133
cc7ec456	134	static struct sk_buff red_peek(struct Qdisc sch)
8e3af978 JP	135	{
	136	struct red_sched_data *q = qdisc_priv(sch);
	137	struct Qdisc *child = q->qdisc;
	138
	139	return child->ops->peek(child);
	140	}
	141
cc7ec456	142	static void red_reset(struct Qdisc *sch)
1da177e4 LT	143	{
	144	struct red_sched_data *q = qdisc_priv(sch);
	145
f38c39d6	146	qdisc_reset(q->qdisc);
d7f4f332	147	sch->qstats.backlog = 0;
f38c39d6	148	sch->q.qlen = 0;
eeca6688	149	red_restart(&q->vars);
1da177e4 LT	150	}
1da177e4 LT	151
602f3baf NF	152	static int red_offload(struct Qdisc *sch, bool enable)
	153	{
	154	struct red_sched_data *q = qdisc_priv(sch);
	155	struct net_device *dev = qdisc_dev(sch);
	156	struct tc_red_qopt_offload opt = {
	157	.handle = sch->handle,
	158	.parent = sch->parent,
	159	};
	160
	161	if (!tc_can_offload(dev) \|\| !dev->netdev_ops->ndo_setup_tc)
	162	return -EOPNOTSUPP;
	163
	164	if (enable) {
	165	opt.command = TC_RED_REPLACE;
	166	opt.set.min = q->parms.qth_min >> q->parms.Wlog;
	167	opt.set.max = q->parms.qth_max >> q->parms.Wlog;
	168	opt.set.probability = q->parms.max_P;
	169	opt.set.is_ecn = red_use_ecn(q);
	170	} else {
	171	opt.command = TC_RED_DESTROY;
	172	}
	173
d772b3a9	174	return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED, &opt);
602f3baf NF	175	}
602f3baf NF	176
f38c39d6 PM	177	static void red_destroy(struct Qdisc *sch)
	178	{
	179	struct red_sched_data *q = qdisc_priv(sch);
8af2a218 ED	180
8af2a218 ED	181	del_timer_sync(&q->adapt_timer);
602f3baf	182	red_offload(sch, false);
f38c39d6 PM	183	qdisc_destroy(q->qdisc);
	184	}
	185
27a3421e PM	186	static const struct nla_policy red_policy[TCA_RED_MAX + 1] = {
	187	[TCA_RED_PARMS] = { .len = sizeof(struct tc_red_qopt) },
	188	[TCA_RED_STAB] = { .len = RED_STAB_SIZE },
a73ed26b	189	[TCA_RED_MAX_P] = { .type = NLA_U32 },
27a3421e PM	190	};
27a3421e PM	191
1e90474c	192	static int red_change(struct Qdisc sch, struct nlattr opt)
1da177e4 LT	193	{
1da177e4 LT	194	struct red_sched_data *q = qdisc_priv(sch);
1e90474c	195	struct nlattr *tb[TCA_RED_MAX + 1];
1da177e4	196	struct tc_red_qopt *ctl;
f38c39d6	197	struct Qdisc *child = NULL;
cee63723	198	int err;
a73ed26b	199	u32 max_P;
1da177e4	200
cee63723	201	if (opt == NULL)
dba051f3 TG	202	return -EINVAL;
dba051f3 TG	203
fceb6435	204	err = nla_parse_nested(tb, TCA_RED_MAX, opt, red_policy, NULL);
cee63723 PM	205	if (err < 0)
	206	return err;
	207
1e90474c	208	if (tb[TCA_RED_PARMS] == NULL \|\|
27a3421e	209	tb[TCA_RED_STAB] == NULL)
1da177e4 LT	210	return -EINVAL;
1da177e4 LT	211
a73ed26b ED	212	max_P = tb[TCA_RED_MAX_P] ? nla_get_u32(tb[TCA_RED_MAX_P]) : 0;
a73ed26b ED	213
1e90474c	214	ctl = nla_data(tb[TCA_RED_PARMS]);
8afa10cb NF	215	if (!red_check_params(ctl->qth_min, ctl->qth_max, ctl->Wlog))
8afa10cb NF	216	return -EINVAL;
1da177e4	217
f38c39d6	218	if (ctl->limit > 0) {
fb0305ce PM	219	child = fifo_create_dflt(sch, &bfifo_qdisc_ops, ctl->limit);
	220	if (IS_ERR(child))
	221	return PTR_ERR(child);
f38c39d6	222
b5bf17ed	223	/* child is fifo, no need to check for noop_qdisc */
49b49971	224	qdisc_hash_add(child, true);
b5bf17ed PA	225	}
b5bf17ed PA	226
1da177e4 LT	227	sch_tree_lock(sch);
1da177e4 LT	228	q->flags = ctl->flags;
1da177e4	229	q->limit = ctl->limit;
5e50da01	230	if (child) {
2ccccf5f WC	231	qdisc_tree_reduce_backlog(q->qdisc, q->qdisc->q.qlen,
2ccccf5f WC	232	q->qdisc->qstats.backlog);
b94c8afc PM	233	qdisc_destroy(q->qdisc);
b94c8afc PM	234	q->qdisc = child;
5e50da01	235	}
1da177e4	236
eeca6688 ED	237	red_set_parms(&q->parms,
eeca6688 ED	238	ctl->qth_min, ctl->qth_max, ctl->Wlog,
a73ed26b ED	239	ctl->Plog, ctl->Scell_log,
	240	nla_data(tb[TCA_RED_STAB]),
	241	max_P);
eeca6688	242	red_set_vars(&q->vars);
6b31b28a	243
8af2a218 ED	244	del_timer(&q->adapt_timer);
	245	if (ctl->flags & TC_RED_ADAPTATIVE)
	246	mod_timer(&q->adapt_timer, jiffies + HZ/2);
	247
1ee5fa1e	248	if (!q->qdisc->q.qlen)
eeca6688	249	red_start_of_idle_period(&q->vars);
dba051f3	250
1da177e4	251	sch_tree_unlock(sch);
602f3baf	252	red_offload(sch, true);
1da177e4 LT	253	return 0;
	254	}
	255
cdeabbb8	256	static inline void red_adaptative_timer(struct timer_list *t)
8af2a218	257	{
cdeabbb8 KC	258	struct red_sched_data *q = from_timer(q, t, adapt_timer);
cdeabbb8 KC	259	struct Qdisc *sch = q->sch;
8af2a218 ED	260	spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
	261
	262	spin_lock(root_lock);
eeca6688	263	red_adaptative_algo(&q->parms, &q->vars);
8af2a218 ED	264	mod_timer(&q->adapt_timer, jiffies + HZ/2);
	265	spin_unlock(root_lock);
	266	}
	267
cc7ec456	268	static int red_init(struct Qdisc sch, struct nlattr opt)
1da177e4	269	{
f38c39d6 PM	270	struct red_sched_data *q = qdisc_priv(sch);
	271
	272	q->qdisc = &noop_qdisc;
cdeabbb8 KC	273	q->sch = sch;
cdeabbb8 KC	274	timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
1da177e4 LT	275	return red_change(sch, opt);
	276	}
	277
428a68af	278	static int red_dump_offload_stats(struct Qdisc sch, struct tc_red_qopt opt)
602f3baf NF	279	{
	280	struct net_device *dev = qdisc_dev(sch);
	281	struct tc_red_qopt_offload hw_stats = {
ee9d3429	282	.command = TC_RED_STATS,
602f3baf NF	283	.handle = sch->handle,
602f3baf NF	284	.parent = sch->parent,
ee9d3429 AM	285	{
	286	.stats.bstats = &sch->bstats,
	287	.stats.qstats = &sch->qstats,
	288	},
602f3baf	289	};
d772b3a9 NF	290	int err;
	291
	292	sch->flags &= ~TCQ_F_OFFLOADED;
602f3baf	293
d772b3a9 NF	294	if (!tc_can_offload(dev) \|\| !dev->netdev_ops->ndo_setup_tc)
	295	return 0;
	296
	297	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_RED,
	298	&hw_stats);
	299	if (err == -EOPNOTSUPP)
602f3baf NF	300	return 0;
602f3baf NF	301
d772b3a9 NF	302	if (!err)
	303	sch->flags \|= TCQ_F_OFFLOADED;
	304
	305	return err;
602f3baf NF	306	}
602f3baf NF	307
1da177e4 LT	308	static int red_dump(struct Qdisc sch, struct sk_buff skb)
	309	{
	310	struct red_sched_data *q = qdisc_priv(sch);
1e90474c	311	struct nlattr *opts = NULL;
6b31b28a TG	312	struct tc_red_qopt opt = {
	313	.limit = q->limit,
	314	.flags = q->flags,
	315	.qth_min = q->parms.qth_min >> q->parms.Wlog,
	316	.qth_max = q->parms.qth_max >> q->parms.Wlog,
	317	.Wlog = q->parms.Wlog,
	318	.Plog = q->parms.Plog,
	319	.Scell_log = q->parms.Scell_log,
	320	};
602f3baf	321	int err;
1da177e4	322
0dfb33a0	323	sch->qstats.backlog = q->qdisc->qstats.backlog;
428a68af	324	err = red_dump_offload_stats(sch, &opt);
602f3baf NF	325	if (err)
	326	goto nla_put_failure;
	327
1e90474c PM	328	opts = nla_nest_start(skb, TCA_OPTIONS);
	329	if (opts == NULL)
	330	goto nla_put_failure;
1b34ec43 DM	331	if (nla_put(skb, TCA_RED_PARMS, sizeof(opt), &opt) \|\|
	332	nla_put_u32(skb, TCA_RED_MAX_P, q->parms.max_P))
	333	goto nla_put_failure;
1e90474c	334	return nla_nest_end(skb, opts);
1da177e4	335
1e90474c	336	nla_put_failure:
bc3ed28c TG	337	nla_nest_cancel(skb, opts);
bc3ed28c TG	338	return -EMSGSIZE;
1da177e4 LT	339	}
	340
	341	static int red_dump_stats(struct Qdisc sch, struct gnet_dump d)
	342	{
	343	struct red_sched_data *q = qdisc_priv(sch);
602f3baf	344	struct net_device *dev = qdisc_dev(sch);
6b31b28a TG	345	struct tc_red_xstats st = {
	346	.early = q->stats.prob_drop + q->stats.forced_drop,
	347	.pdrop = q->stats.pdrop,
	348	.other = q->stats.other,
	349	.marked = q->stats.prob_mark + q->stats.forced_mark,
	350	};
	351
428a68af	352	if (sch->flags & TCQ_F_OFFLOADED) {
602f3baf NF	353	struct red_stats hw_stats = {0};
602f3baf NF	354	struct tc_red_qopt_offload hw_stats_request = {
ee9d3429	355	.command = TC_RED_XSTATS,
602f3baf NF	356	.handle = sch->handle,
602f3baf NF	357	.parent = sch->parent,
ee9d3429 AM	358	{
	359	.xstats = &hw_stats,
	360	},
602f3baf NF	361	};
	362	if (!dev->netdev_ops->ndo_setup_tc(dev,
	363	TC_SETUP_QDISC_RED,
	364	&hw_stats_request)) {
	365	st.early += hw_stats.prob_drop + hw_stats.forced_drop;
	366	st.pdrop += hw_stats.pdrop;
	367	st.other += hw_stats.other;
	368	st.marked += hw_stats.prob_mark + hw_stats.forced_mark;
	369	}
	370	}
	371
6b31b28a	372	return gnet_stats_copy_app(d, &st, sizeof(st));
1da177e4 LT	373	}
1da177e4 LT	374
f38c39d6 PM	375	static int red_dump_class(struct Qdisc *sch, unsigned long cl,
	376	struct sk_buff skb, struct tcmsg tcm)
	377	{
	378	struct red_sched_data *q = qdisc_priv(sch);
	379
f38c39d6 PM	380	tcm->tcm_handle \|= TC_H_MIN(1);
	381	tcm->tcm_info = q->qdisc->handle;
	382	return 0;
	383	}
	384
	385	static int red_graft(struct Qdisc sch, unsigned long arg, struct Qdisc new,
	386	struct Qdisc **old)
	387	{
	388	struct red_sched_data *q = qdisc_priv(sch);
	389
	390	if (new == NULL)
	391	new = &noop_qdisc;
	392
86a7996c	393	*old = qdisc_replace(sch, new, &q->qdisc);
f38c39d6 PM	394	return 0;
	395	}
	396
	397	static struct Qdisc red_leaf(struct Qdisc sch, unsigned long arg)
	398	{
	399	struct red_sched_data *q = qdisc_priv(sch);
	400	return q->qdisc;
	401	}
	402
143976ce	403	static unsigned long red_find(struct Qdisc *sch, u32 classid)
f38c39d6 PM	404	{
	405	return 1;
	406	}
	407
f38c39d6 PM	408	static void red_walk(struct Qdisc sch, struct qdisc_walker walker)
	409	{
	410	if (!walker->stop) {
	411	if (walker->count >= walker->skip)
	412	if (walker->fn(sch, 1, walker) < 0) {
	413	walker->stop = 1;
	414	return;
	415	}
	416	walker->count++;
	417	}
	418	}
	419
20fea08b	420	static const struct Qdisc_class_ops red_class_ops = {
f38c39d6 PM	421	.graft = red_graft,
f38c39d6 PM	422	.leaf = red_leaf,
143976ce	423	.find = red_find,
f38c39d6	424	.walk = red_walk,
f38c39d6 PM	425	.dump = red_dump_class,
	426	};
	427
20fea08b	428	static struct Qdisc_ops red_qdisc_ops __read_mostly = {
1da177e4 LT	429	.id = "red",
1da177e4 LT	430	.priv_size = sizeof(struct red_sched_data),
f38c39d6	431	.cl_ops = &red_class_ops,
1da177e4 LT	432	.enqueue = red_enqueue,
1da177e4 LT	433	.dequeue = red_dequeue,
8e3af978	434	.peek = red_peek,
1da177e4 LT	435	.init = red_init,
1da177e4 LT	436	.reset = red_reset,
f38c39d6	437	.destroy = red_destroy,
1da177e4 LT	438	.change = red_change,
	439	.dump = red_dump,
	440	.dump_stats = red_dump_stats,
	441	.owner = THIS_MODULE,
	442	};
	443
	444	static int __init red_module_init(void)
	445	{
	446	return register_qdisc(&red_qdisc_ops);
	447	}
dba051f3 TG	448
dba051f3 TG	449	static void __exit red_module_exit(void)
1da177e4 LT	450	{
	451	unregister_qdisc(&red_qdisc_ops);
	452	}
dba051f3	453
1da177e4 LT	454	module_init(red_module_init)
1da177e4 LT	455	module_exit(red_module_exit)
dba051f3	456
1da177e4	457	MODULE_LICENSE("GPL");