net/sched/sch_gred.c - kernel/msm-4.9 - Gitiles

 /*
  * net/sched/sch_gred.c	Generic 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:    J Hadi Salim (hadi@cyberus.ca) 1998-2002
  *
  *             991129: -  Bug fix with grio mode
  *		       - a better sing. AvgQ mode with Grio(WRED)
  *		       - A finer grained VQ dequeue based on sugestion
  *		         from Ren Liu
  *		       - More error checks
  *
  *  For all the glorious comments look at include/net/red.h
  */

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

 #define GRED_DEF_PRIO (MAX_DPs / 2)
 #define GRED_VQ_MASK (MAX_DPs - 1)

 struct gred_sched_data;
 struct gred_sched;

 struct gred_sched_data
 {
 	u32		limit;		/* HARD maximal queue length	*/
 	u32      	DP;		/* the drop pramaters */
 	u32		bytesin;	/* bytes seen on virtualQ so far*/
 	u32		packetsin;	/* packets seen on virtualQ so far*/
 	u32		backlog;	/* bytes on the virtualQ */
 	u8		prio;		/* the prio of this vq */

 	struct red_parms parms;
 	struct red_stats stats;
 };

 enum {
 	GRED_WRED_MODE = 1,
 	GRED_RIO_MODE,
 };

 struct gred_sched
 {
 	struct gred_sched_data *tab[MAX_DPs];
 	unsigned long	flags;
 	u32		red_flags;
 	u32 		DPs;
 	u32 		def;
 	struct red_parms wred_set;
 };

 static inline int gred_wred_mode(struct gred_sched *table)
 {
 	return test_bit(GRED_WRED_MODE, &table->flags);
 }

 static inline void gred_enable_wred_mode(struct gred_sched *table)
 {
 	__set_bit(GRED_WRED_MODE, &table->flags);
 }

 static inline void gred_disable_wred_mode(struct gred_sched *table)
 {
 	__clear_bit(GRED_WRED_MODE, &table->flags);
 }

 static inline int gred_rio_mode(struct gred_sched *table)
 {
 	return test_bit(GRED_RIO_MODE, &table->flags);
 }

 static inline void gred_enable_rio_mode(struct gred_sched *table)
 {
 	__set_bit(GRED_RIO_MODE, &table->flags);
 }

 static inline void gred_disable_rio_mode(struct gred_sched *table)
 {
 	__clear_bit(GRED_RIO_MODE, &table->flags);
 }

 static inline int gred_wred_mode_check(struct Qdisc *sch)
 {
 	struct gred_sched *table = qdisc_priv(sch);
 	int i;

 	/* Really ugly O(n^2) but shouldn't be necessary too frequent. */
 	for (i = 0; i < table->DPs; i++) {
 		struct gred_sched_data *q = table->tab[i];
 		int n;

 		if (q == NULL)
 			continue;

 		for (n = 0; n < table->DPs; n++)
 			if (table->tab[n] && table->tab[n] != q &&
 			    table->tab[n]->prio == q->prio)
 				return 1;
 	}

 	return 0;
 }

 static inline unsigned int gred_backlog(struct gred_sched *table,
 					struct gred_sched_data *q,
 					struct Qdisc *sch)
 {
 	if (gred_wred_mode(table))
 		return sch->qstats.backlog;
 	else
 		return q->backlog;
 }

 static inline u16 tc_index_to_dp(struct sk_buff *skb)
 {
 	return skb->tc_index & GRED_VQ_MASK;
 }

 static inline void gred_load_wred_set(struct gred_sched *table,
 				      struct gred_sched_data *q)
 {
 	q->parms.qavg = table->wred_set.qavg;
 	q->parms.qidlestart = table->wred_set.qidlestart;
 }

 static inline void gred_store_wred_set(struct gred_sched *table,
 				       struct gred_sched_data *q)
 {
 	table->wred_set.qavg = q->parms.qavg;
 }

 static inline int gred_use_ecn(struct gred_sched *t)
 {
 	return t->red_flags & TC_RED_ECN;
 }

 static inline int gred_use_harddrop(struct gred_sched *t)
 {
 	return t->red_flags & TC_RED_HARDDROP;
 }

 static int gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 {
 	struct gred_sched_data *q=NULL;
 	struct gred_sched *t= qdisc_priv(sch);
 	unsigned long qavg = 0;
 	u16 dp = tc_index_to_dp(skb);

 	if (dp >= t->DPs  || (q = t->tab[dp]) == NULL) {
 		dp = t->def;

 		if ((q = t->tab[dp]) == NULL) {
 			/* Pass through packets not assigned to a DP
 			 * if no default DP has been configured. This
 			 * allows for DP flows to be left untouched.
 			 */
 			if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
 				return qdisc_enqueue_tail(skb, sch);
 			else
 				goto drop;
 		}

 		/* fix tc_index? --could be controvesial but needed for
 		   requeueing */
 		skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
 	}

 	/* sum up all the qaves of prios <= to ours to get the new qave */
 	if (!gred_wred_mode(t) && gred_rio_mode(t)) {
 		int i;

 		for (i = 0; i < t->DPs; i++) {
 			if (t->tab[i] && t->tab[i]->prio < q->prio &&
 			    !red_is_idling(&t->tab[i]->parms))
 				qavg +=t->tab[i]->parms.qavg;
 		}

 	}

 	q->packetsin++;
 	q->bytesin += skb->len;

 	if (gred_wred_mode(t))
 		gred_load_wred_set(t, q);

 	q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));

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

 	if (gred_wred_mode(t))
 		gred_store_wred_set(t, q);

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

 		case RED_PROB_MARK:
 			sch->qstats.overlimits++;
 			if (!gred_use_ecn(t) || !INET_ECN_set_ce(skb)) {
 				q->stats.prob_drop++;
 				goto congestion_drop;
 			}

 			q->stats.prob_mark++;
 			break;

 		case RED_HARD_MARK:
 			sch->qstats.overlimits++;
 			if (gred_use_harddrop(t) || !gred_use_ecn(t) ||
 			    !INET_ECN_set_ce(skb)) {
 				q->stats.forced_drop++;
 				goto congestion_drop;
 			}
 			q->stats.forced_mark++;
 			break;
 	}

 	if (q->backlog + skb->len <= q->limit) {
 		q->backlog += skb->len;
 		return qdisc_enqueue_tail(skb, sch);
 	}

 	q->stats.pdrop++;
 drop:
 	return qdisc_drop(skb, sch);

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

 static int gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
 {
 	struct gred_sched *t = qdisc_priv(sch);
 	struct gred_sched_data *q;
 	u16 dp = tc_index_to_dp(skb);

 	if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 		if (net_ratelimit())
 			printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
 			       "for requeue, screwing up backlog.\n",
 			       tc_index_to_dp(skb));
 	} else {
 		if (red_is_idling(&q->parms))
 			red_end_of_idle_period(&q->parms);
 		q->backlog += skb->len;
 	}

 	return qdisc_requeue(skb, sch);
 }

 static struct sk_buff *gred_dequeue(struct Qdisc* sch)
 {
 	struct sk_buff *skb;
 	struct gred_sched *t = qdisc_priv(sch);

 	skb = qdisc_dequeue_head(sch);

 	if (skb) {
 		struct gred_sched_data *q;
 		u16 dp = tc_index_to_dp(skb);

 		if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 			if (net_ratelimit())
 				printk(KERN_WARNING "GRED: Unable to relocate "
 				       "VQ 0x%x after dequeue, screwing up "
 				       "backlog.\n", tc_index_to_dp(skb));
 		} else {
 			q->backlog -= skb->len;

 			if (!q->backlog && !gred_wred_mode(t))
 				red_start_of_idle_period(&q->parms);
 		}

 		return skb;
 	}

 	if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
 		red_start_of_idle_period(&t->wred_set);

 	return NULL;
 }

 static unsigned int gred_drop(struct Qdisc* sch)
 {
 	struct sk_buff *skb;
 	struct gred_sched *t = qdisc_priv(sch);

 	skb = qdisc_dequeue_tail(sch);
 	if (skb) {
 		unsigned int len = skb->len;
 		struct gred_sched_data *q;
 		u16 dp = tc_index_to_dp(skb);

 		if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 			if (net_ratelimit())
 				printk(KERN_WARNING "GRED: Unable to relocate "
 				       "VQ 0x%x while dropping, screwing up "
 				       "backlog.\n", tc_index_to_dp(skb));
 		} else {
 			q->backlog -= len;
 			q->stats.other++;

 			if (!q->backlog && !gred_wred_mode(t))
 				red_start_of_idle_period(&q->parms);
 		}

 		qdisc_drop(skb, sch);
 		return len;
 	}

 	if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
 		red_start_of_idle_period(&t->wred_set);

 	return 0;

 }

 static void gred_reset(struct Qdisc* sch)
 {
 	int i;
 	struct gred_sched *t = qdisc_priv(sch);

 	qdisc_reset_queue(sch);

 	for (i = 0; i < t->DPs; i++) {
 		struct gred_sched_data *q = t->tab[i];

 		if (!q)
 			continue;

 		red_restart(&q->parms);
 		q->backlog = 0;
 	}
 }

 static inline void gred_destroy_vq(struct gred_sched_data *q)
 {
 	kfree(q);
 }

 static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
 {
 	struct gred_sched *table = qdisc_priv(sch);
 	struct tc_gred_sopt *sopt;
 	int i;

 	if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
 		return -EINVAL;

 	sopt = RTA_DATA(dps);

 	if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
 		return -EINVAL;

 	sch_tree_lock(sch);
 	table->DPs = sopt->DPs;
 	table->def = sopt->def_DP;
 	table->red_flags = sopt->flags;

 	/*
 	 * Every entry point to GRED is synchronized with the above code
 	 * and the DP is checked against DPs, i.e. shadowed VQs can no
 	 * longer be found so we can unlock right here.
 	 */
 	sch_tree_unlock(sch);

 	if (sopt->grio) {
 		gred_enable_rio_mode(table);
 		gred_disable_wred_mode(table);
 		if (gred_wred_mode_check(sch))
 			gred_enable_wred_mode(table);
 	} else {
 		gred_disable_rio_mode(table);
 		gred_disable_wred_mode(table);
 	}

 	for (i = table->DPs; i < MAX_DPs; i++) {
 		if (table->tab[i]) {
 			printk(KERN_WARNING "GRED: Warning: Destroying "
 			       "shadowed VQ 0x%x\n", i);
 			gred_destroy_vq(table->tab[i]);
 			table->tab[i] = NULL;
 		}
 	}

 	return 0;
 }

 static inline int gred_change_vq(struct Qdisc *sch, int dp,
 				 struct tc_gred_qopt *ctl, int prio, u8 *stab)
 {
 	struct gred_sched *table = qdisc_priv(sch);
 	struct gred_sched_data *q;

 	if (table->tab[dp] == NULL) {
 		table->tab[dp] = kzalloc(sizeof(*q), GFP_KERNEL);
 		if (table->tab[dp] == NULL)
 			return -ENOMEM;
 	}

 	q = table->tab[dp];
 	q->DP = dp;
 	q->prio = prio;
 	q->limit = ctl->limit;

 	if (q->backlog == 0)
 		red_end_of_idle_period(&q->parms);

 	red_set_parms(&q->parms,
 		      ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
 		      ctl->Scell_log, stab);

 	return 0;
 }

 static int gred_change(struct Qdisc *sch, struct rtattr *opt)
 {
 	struct gred_sched *table = qdisc_priv(sch);
 	struct tc_gred_qopt *ctl;
 	struct rtattr *tb[TCA_GRED_MAX];
 	int err = -EINVAL, prio = GRED_DEF_PRIO;
 	u8 *stab;

 	if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
 		return -EINVAL;

 	if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
 		return gred_change_table_def(sch, opt);

 	if (tb[TCA_GRED_PARMS-1] == NULL ||
 	    RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
 	    tb[TCA_GRED_STAB-1] == NULL ||
 	    RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
 		return -EINVAL;

 	ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
 	stab = RTA_DATA(tb[TCA_GRED_STAB-1]);

 	if (ctl->DP >= table->DPs)
 		goto errout;

 	if (gred_rio_mode(table)) {
 		if (ctl->prio == 0) {
 			int def_prio = GRED_DEF_PRIO;

 			if (table->tab[table->def])
 				def_prio = table->tab[table->def]->prio;

 			printk(KERN_DEBUG "GRED: DP %u does not have a prio "
 			       "setting default to %d\n", ctl->DP, def_prio);

 			prio = def_prio;
 		} else
 			prio = ctl->prio;
 	}

 	sch_tree_lock(sch);

 	err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
 	if (err < 0)
 		goto errout_locked;

 	if (gred_rio_mode(table)) {
 		gred_disable_wred_mode(table);
 		if (gred_wred_mode_check(sch))
 			gred_enable_wred_mode(table);
 	}

 	err = 0;

 errout_locked:
 	sch_tree_unlock(sch);
 errout:
 	return err;
 }

 static int gred_init(struct Qdisc *sch, struct rtattr *opt)
 {
 	struct rtattr *tb[TCA_GRED_MAX];

 	if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
 		return -EINVAL;

 	if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
 		return -EINVAL;

 	return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
 }

 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct gred_sched *table = qdisc_priv(sch);
 	struct rtattr *parms, *opts = NULL;
 	int i;
 	struct tc_gred_sopt sopt = {
 		.DPs	= table->DPs,
 		.def_DP	= table->def,
 		.grio	= gred_rio_mode(table),
 		.flags	= table->red_flags,
 	};

 	opts = RTA_NEST(skb, TCA_OPTIONS);
 	RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
 	parms = RTA_NEST(skb, TCA_GRED_PARMS);

 	for (i = 0; i < MAX_DPs; i++) {
 		struct gred_sched_data *q = table->tab[i];
 		struct tc_gred_qopt opt;

 		memset(&opt, 0, sizeof(opt));

 		if (!q) {
 			/* hack -- fix at some point with proper message
 			   This is how we indicate to tc that there is no VQ
 			   at this DP */

 			opt.DP = MAX_DPs + i;
 			goto append_opt;
 		}

 		opt.limit	= q->limit;
 		opt.DP		= q->DP;
 		opt.backlog	= q->backlog;
 		opt.prio	= q->prio;
 		opt.qth_min	= q->parms.qth_min >> q->parms.Wlog;
 		opt.qth_max	= q->parms.qth_max >> q->parms.Wlog;
 		opt.Wlog	= q->parms.Wlog;
 		opt.Plog	= q->parms.Plog;
 		opt.Scell_log	= q->parms.Scell_log;
 		opt.other	= q->stats.other;
 		opt.early	= q->stats.prob_drop;
 		opt.forced	= q->stats.forced_drop;
 		opt.pdrop	= q->stats.pdrop;
 		opt.packets	= q->packetsin;
 		opt.bytesin	= q->bytesin;

 		if (gred_wred_mode(table)) {
 			q->parms.qidlestart =
 				table->tab[table->def]->parms.qidlestart;
 			q->parms.qavg = table->tab[table->def]->parms.qavg;
 		}

 		opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);

 append_opt:
 		RTA_APPEND(skb, sizeof(opt), &opt);
 	}

 	RTA_NEST_END(skb, parms);

 	return RTA_NEST_END(skb, opts);

 rtattr_failure:
 	return RTA_NEST_CANCEL(skb, opts);
 }

 static void gred_destroy(struct Qdisc *sch)
 {
 	struct gred_sched *table = qdisc_priv(sch);
 	int i;

 	for (i = 0; i < table->DPs; i++) {
 		if (table->tab[i])
 			gred_destroy_vq(table->tab[i]);
 	}
 }

 static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
 	.id		=	"gred",
 	.priv_size	=	sizeof(struct gred_sched),
 	.enqueue	=	gred_enqueue,
 	.dequeue	=	gred_dequeue,
 	.requeue	=	gred_requeue,
 	.drop		=	gred_drop,
 	.init		=	gred_init,
 	.reset		=	gred_reset,
 	.destroy	=	gred_destroy,
 	.change		=	gred_change,
 	.dump		=	gred_dump,
 	.owner		=	THIS_MODULE,
 };

 static int __init gred_module_init(void)
 {
 	return register_qdisc(&gred_qdisc_ops);
 }

 static void __exit gred_module_exit(void)
 {
 	unregister_qdisc(&gred_qdisc_ops);
 }

 module_init(gred_module_init)
 module_exit(gred_module_exit)

 MODULE_LICENSE("GPL");
	/*
	* net/sched/sch_gred.c Generic 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: J Hadi Salim (hadi@cyberus.ca) 1998-2002
	*
	* 991129: - Bug fix with grio mode
	* - a better sing. AvgQ mode with Grio(WRED)
	* - A finer grained VQ dequeue based on sugestion
	* from Ren Liu
	* - More error checks
	*
	* For all the glorious comments look at include/net/red.h
	*/

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

	#define GRED_DEF_PRIO (MAX_DPs / 2)
	#define GRED_VQ_MASK (MAX_DPs - 1)

	struct gred_sched_data;
	struct gred_sched;

	struct gred_sched_data
	{
	u32 limit; /* HARD maximal queue length */
	u32 DP; /* the drop pramaters */
	u32 bytesin; /* bytes seen on virtualQ so far*/
	u32 packetsin; /* packets seen on virtualQ so far*/
	u32 backlog; /* bytes on the virtualQ */
	u8 prio; /* the prio of this vq */

	struct red_parms parms;
	struct red_stats stats;
	};

	enum {
	GRED_WRED_MODE = 1,
	GRED_RIO_MODE,
	};

	struct gred_sched
	{
	struct gred_sched_data *tab[MAX_DPs];
	unsigned long flags;
	u32 red_flags;
	u32 DPs;
	u32 def;
	struct red_parms wred_set;
	};

	static inline int gred_wred_mode(struct gred_sched *table)
	{
	return test_bit(GRED_WRED_MODE, &table->flags);
	}

	static inline void gred_enable_wred_mode(struct gred_sched *table)
	{
	__set_bit(GRED_WRED_MODE, &table->flags);
	}

	static inline void gred_disable_wred_mode(struct gred_sched *table)
	{
	__clear_bit(GRED_WRED_MODE, &table->flags);
	}

	static inline int gred_rio_mode(struct gred_sched *table)
	{
	return test_bit(GRED_RIO_MODE, &table->flags);
	}

	static inline void gred_enable_rio_mode(struct gred_sched *table)
	{
	__set_bit(GRED_RIO_MODE, &table->flags);
	}

	static inline void gred_disable_rio_mode(struct gred_sched *table)
	{
	__clear_bit(GRED_RIO_MODE, &table->flags);
	}

	static inline int gred_wred_mode_check(struct Qdisc *sch)
	{
	struct gred_sched *table = qdisc_priv(sch);
	int i;

	/* Really ugly O(n^2) but shouldn't be necessary too frequent. */
	for (i = 0; i < table->DPs; i++) {
	struct gred_sched_data *q = table->tab[i];
	int n;

	if (q == NULL)
	continue;

	for (n = 0; n < table->DPs; n++)
	if (table->tab[n] && table->tab[n] != q &&
	table->tab[n]->prio == q->prio)
	return 1;
	}

	return 0;
	}

	static inline unsigned int gred_backlog(struct gred_sched *table,
	struct gred_sched_data *q,
	struct Qdisc *sch)
	{
	if (gred_wred_mode(table))
	return sch->qstats.backlog;
	else
	return q->backlog;
	}

	static inline u16 tc_index_to_dp(struct sk_buff *skb)
	{
	return skb->tc_index & GRED_VQ_MASK;
	}

	static inline void gred_load_wred_set(struct gred_sched *table,
	struct gred_sched_data *q)
	{
	q->parms.qavg = table->wred_set.qavg;
	q->parms.qidlestart = table->wred_set.qidlestart;
	}

	static inline void gred_store_wred_set(struct gred_sched *table,
	struct gred_sched_data *q)
	{
	table->wred_set.qavg = q->parms.qavg;
	}

	static inline int gred_use_ecn(struct gred_sched *t)
	{
	return t->red_flags & TC_RED_ECN;
	}

	static inline int gred_use_harddrop(struct gred_sched *t)
	{
	return t->red_flags & TC_RED_HARDDROP;
	}

	static int gred_enqueue(struct sk_buff skb, struct Qdisc sch)
	{
	struct gred_sched_data *q=NULL;
	struct gred_sched *t= qdisc_priv(sch);
	unsigned long qavg = 0;
	u16 dp = tc_index_to_dp(skb);

	if (dp >= t->DPs \|\| (q = t->tab[dp]) == NULL) {
	dp = t->def;

	if ((q = t->tab[dp]) == NULL) {
	/* Pass through packets not assigned to a DP
	* if no default DP has been configured. This
	* allows for DP flows to be left untouched.
	*/
	if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
	return qdisc_enqueue_tail(skb, sch);
	else
	goto drop;
	}

	/* fix tc_index? --could be controvesial but needed for
	requeueing */
	skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) \| dp;
	}

	/* sum up all the qaves of prios <= to ours to get the new qave */
	if (!gred_wred_mode(t) && gred_rio_mode(t)) {
	int i;

	for (i = 0; i < t->DPs; i++) {
	if (t->tab[i] && t->tab[i]->prio < q->prio &&
	!red_is_idling(&t->tab[i]->parms))
	qavg +=t->tab[i]->parms.qavg;
	}

	}

	q->packetsin++;
	q->bytesin += skb->len;

	if (gred_wred_mode(t))
	gred_load_wred_set(t, q);

	q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));

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

	if (gred_wred_mode(t))
	gred_store_wred_set(t, q);

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

	case RED_PROB_MARK:
	sch->qstats.overlimits++;
	if (!gred_use_ecn(t) \|\| !INET_ECN_set_ce(skb)) {
	q->stats.prob_drop++;
	goto congestion_drop;
	}

	q->stats.prob_mark++;
	break;

	case RED_HARD_MARK:
	sch->qstats.overlimits++;
	if (gred_use_harddrop(t) \|\| !gred_use_ecn(t) \|\|
	!INET_ECN_set_ce(skb)) {
	q->stats.forced_drop++;
	goto congestion_drop;
	}
	q->stats.forced_mark++;
	break;
	}

	if (q->backlog + skb->len <= q->limit) {
	q->backlog += skb->len;
	return qdisc_enqueue_tail(skb, sch);
	}

	q->stats.pdrop++;
	drop:
	return qdisc_drop(skb, sch);

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

	static int gred_requeue(struct sk_buff skb, struct Qdisc sch)
	{
	struct gred_sched *t = qdisc_priv(sch);
	struct gred_sched_data *q;
	u16 dp = tc_index_to_dp(skb);

	if (dp >= t->DPs \|\| (q = t->tab[dp]) == NULL) {
	if (net_ratelimit())
	printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
	"for requeue, screwing up backlog.\n",
	tc_index_to_dp(skb));
	} else {
	if (red_is_idling(&q->parms))
	red_end_of_idle_period(&q->parms);
	q->backlog += skb->len;
	}

	return qdisc_requeue(skb, sch);
	}

	static struct sk_buff gred_dequeue(struct Qdisc sch)
	{
	struct sk_buff *skb;
	struct gred_sched *t = qdisc_priv(sch);

	skb = qdisc_dequeue_head(sch);

	if (skb) {
	struct gred_sched_data *q;
	u16 dp = tc_index_to_dp(skb);

	if (dp >= t->DPs \|\| (q = t->tab[dp]) == NULL) {
	if (net_ratelimit())
	printk(KERN_WARNING "GRED: Unable to relocate "
	"VQ 0x%x after dequeue, screwing up "
	"backlog.\n", tc_index_to_dp(skb));
	} else {
	q->backlog -= skb->len;

	if (!q->backlog && !gred_wred_mode(t))
	red_start_of_idle_period(&q->parms);
	}

	return skb;
	}

	if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
	red_start_of_idle_period(&t->wred_set);

	return NULL;
	}

	static unsigned int gred_drop(struct Qdisc* sch)
	{
	struct sk_buff *skb;
	struct gred_sched *t = qdisc_priv(sch);

	skb = qdisc_dequeue_tail(sch);
	if (skb) {
	unsigned int len = skb->len;
	struct gred_sched_data *q;
	u16 dp = tc_index_to_dp(skb);

	if (dp >= t->DPs \|\| (q = t->tab[dp]) == NULL) {
	if (net_ratelimit())
	printk(KERN_WARNING "GRED: Unable to relocate "
	"VQ 0x%x while dropping, screwing up "
	"backlog.\n", tc_index_to_dp(skb));
	} else {
	q->backlog -= len;
	q->stats.other++;

	if (!q->backlog && !gred_wred_mode(t))
	red_start_of_idle_period(&q->parms);
	}

	qdisc_drop(skb, sch);
	return len;
	}

	if (gred_wred_mode(t) && !red_is_idling(&t->wred_set))
	red_start_of_idle_period(&t->wred_set);

	return 0;

	}

	static void gred_reset(struct Qdisc* sch)
	{
	int i;
	struct gred_sched *t = qdisc_priv(sch);

	qdisc_reset_queue(sch);

	for (i = 0; i < t->DPs; i++) {
	struct gred_sched_data *q = t->tab[i];

	if (!q)
	continue;

	red_restart(&q->parms);
	q->backlog = 0;
	}
	}

	static inline void gred_destroy_vq(struct gred_sched_data *q)
	{
	kfree(q);
	}

	static inline int gred_change_table_def(struct Qdisc sch, struct rtattr dps)
	{
	struct gred_sched *table = qdisc_priv(sch);
	struct tc_gred_sopt *sopt;
	int i;

	if (dps == NULL \|\| RTA_PAYLOAD(dps) < sizeof(*sopt))
	return -EINVAL;

	sopt = RTA_DATA(dps);

	if (sopt->DPs > MAX_DPs \|\| sopt->DPs == 0 \|\| sopt->def_DP >= sopt->DPs)
	return -EINVAL;

	sch_tree_lock(sch);
	table->DPs = sopt->DPs;
	table->def = sopt->def_DP;
	table->red_flags = sopt->flags;

	/*
	* Every entry point to GRED is synchronized with the above code
	* and the DP is checked against DPs, i.e. shadowed VQs can no
	* longer be found so we can unlock right here.
	*/
	sch_tree_unlock(sch);

	if (sopt->grio) {
	gred_enable_rio_mode(table);
	gred_disable_wred_mode(table);
	if (gred_wred_mode_check(sch))
	gred_enable_wred_mode(table);
	} else {
	gred_disable_rio_mode(table);
	gred_disable_wred_mode(table);
	}

	for (i = table->DPs; i < MAX_DPs; i++) {
	if (table->tab[i]) {
	printk(KERN_WARNING "GRED: Warning: Destroying "
	"shadowed VQ 0x%x\n", i);
	gred_destroy_vq(table->tab[i]);
	table->tab[i] = NULL;
	}
	}

	return 0;
	}

	static inline int gred_change_vq(struct Qdisc *sch, int dp,
	struct tc_gred_qopt ctl, int prio, u8 stab)
	{
	struct gred_sched *table = qdisc_priv(sch);
	struct gred_sched_data *q;

	if (table->tab[dp] == NULL) {
	table->tab[dp] = kzalloc(sizeof(*q), GFP_KERNEL);
	if (table->tab[dp] == NULL)
	return -ENOMEM;
	}

	q = table->tab[dp];
	q->DP = dp;
	q->prio = prio;
	q->limit = ctl->limit;

	if (q->backlog == 0)
	red_end_of_idle_period(&q->parms);

	red_set_parms(&q->parms,
	ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
	ctl->Scell_log, stab);

	return 0;
	}

	static int gred_change(struct Qdisc sch, struct rtattr opt)
	{
	struct gred_sched *table = qdisc_priv(sch);
	struct tc_gred_qopt *ctl;
	struct rtattr *tb[TCA_GRED_MAX];
	int err = -EINVAL, prio = GRED_DEF_PRIO;
	u8 *stab;

	if (opt == NULL \|\| rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
	return -EINVAL;

	if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
	return gred_change_table_def(sch, opt);

	if (tb[TCA_GRED_PARMS-1] == NULL \|\|
	RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) \|\|
	tb[TCA_GRED_STAB-1] == NULL \|\|
	RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
	return -EINVAL;

	ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
	stab = RTA_DATA(tb[TCA_GRED_STAB-1]);

	if (ctl->DP >= table->DPs)
	goto errout;

	if (gred_rio_mode(table)) {
	if (ctl->prio == 0) {
	int def_prio = GRED_DEF_PRIO;

	if (table->tab[table->def])
	def_prio = table->tab[table->def]->prio;

	printk(KERN_DEBUG "GRED: DP %u does not have a prio "
	"setting default to %d\n", ctl->DP, def_prio);

	prio = def_prio;
	} else
	prio = ctl->prio;
	}

	sch_tree_lock(sch);

	err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
	if (err < 0)
	goto errout_locked;

	if (gred_rio_mode(table)) {
	gred_disable_wred_mode(table);
	if (gred_wred_mode_check(sch))
	gred_enable_wred_mode(table);
	}

	err = 0;

	errout_locked:
	sch_tree_unlock(sch);
	errout:
	return err;
	}

	static int gred_init(struct Qdisc sch, struct rtattr opt)
	{
	struct rtattr *tb[TCA_GRED_MAX];

	if (opt == NULL \|\| rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
	return -EINVAL;

	if (tb[TCA_GRED_PARMS-1] \|\| tb[TCA_GRED_STAB-1])
	return -EINVAL;

	return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
	}

	static int gred_dump(struct Qdisc sch, struct sk_buff skb)
	{
	struct gred_sched *table = qdisc_priv(sch);
	struct rtattr parms, opts = NULL;
	int i;
	struct tc_gred_sopt sopt = {
	.DPs = table->DPs,
	.def_DP = table->def,
	.grio = gred_rio_mode(table),
	.flags = table->red_flags,
	};

	opts = RTA_NEST(skb, TCA_OPTIONS);
	RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
	parms = RTA_NEST(skb, TCA_GRED_PARMS);

	for (i = 0; i < MAX_DPs; i++) {
	struct gred_sched_data *q = table->tab[i];
	struct tc_gred_qopt opt;

	memset(&opt, 0, sizeof(opt));

	if (!q) {
	/* hack -- fix at some point with proper message
	This is how we indicate to tc that there is no VQ
	at this DP */

	opt.DP = MAX_DPs + i;
	goto append_opt;
	}

	opt.limit = q->limit;
	opt.DP = q->DP;
	opt.backlog = q->backlog;
	opt.prio = q->prio;
	opt.qth_min = q->parms.qth_min >> q->parms.Wlog;
	opt.qth_max = q->parms.qth_max >> q->parms.Wlog;
	opt.Wlog = q->parms.Wlog;
	opt.Plog = q->parms.Plog;
	opt.Scell_log = q->parms.Scell_log;
	opt.other = q->stats.other;
	opt.early = q->stats.prob_drop;
	opt.forced = q->stats.forced_drop;
	opt.pdrop = q->stats.pdrop;
	opt.packets = q->packetsin;
	opt.bytesin = q->bytesin;

	if (gred_wred_mode(table)) {
	q->parms.qidlestart =
	table->tab[table->def]->parms.qidlestart;
	q->parms.qavg = table->tab[table->def]->parms.qavg;
	}

	opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);

	append_opt:
	RTA_APPEND(skb, sizeof(opt), &opt);
	}

	RTA_NEST_END(skb, parms);

	return RTA_NEST_END(skb, opts);

	rtattr_failure:
	return RTA_NEST_CANCEL(skb, opts);
	}

	static void gred_destroy(struct Qdisc *sch)
	{
	struct gred_sched *table = qdisc_priv(sch);
	int i;

	for (i = 0; i < table->DPs; i++) {
	if (table->tab[i])
	gred_destroy_vq(table->tab[i]);
	}
	}

	static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
	.id = "gred",
	.priv_size = sizeof(struct gred_sched),
	.enqueue = gred_enqueue,
	.dequeue = gred_dequeue,
	.requeue = gred_requeue,
	.drop = gred_drop,
	.init = gred_init,
	.reset = gred_reset,
	.destroy = gred_destroy,
	.change = gred_change,
	.dump = gred_dump,
	.owner = THIS_MODULE,
	};

	static int __init gred_module_init(void)
	{
	return register_qdisc(&gred_qdisc_ops);
	}

	static void __exit gred_module_exit(void)
	{
	unregister_qdisc(&gred_qdisc_ops);
	}

	module_init(gred_module_init)
	module_exit(gred_module_exit)

	MODULE_LICENSE("GPL");