Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1823 insertions, 0 deletions

diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
new file mode 100644
index 000000000..0a76ad05e
--- /dev/null
+++ b/net/sched/sch_cbq.c
@@ -0,0 +1,1823 @@
+/*
+ * net/sched/sch_cbq.c	Class-Based Queueing discipline.
+ *
+ *		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>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
+
+
+/*	Class-Based Queueing (CBQ) algorithm.
+	=======================================
+
+	Sources: [1] Sally Floyd and Van Jacobson, "Link-sharing and Resource
+		 Management Models for Packet Networks",
+		 IEEE/ACM Transactions on Networking, Vol.3, No.4, 1995
+
+		 [2] Sally Floyd, "Notes on CBQ and Guaranteed Service", 1995
+
+		 [3] Sally Floyd, "Notes on Class-Based Queueing: Setting
+		 Parameters", 1996
+
+		 [4] Sally Floyd and Michael Speer, "Experimental Results
+		 for Class-Based Queueing", 1998, not published.
+
+	-----------------------------------------------------------------------
+
+	Algorithm skeleton was taken from NS simulator cbq.cc.
+	If someone wants to check this code against the LBL version,
+	he should take into account that ONLY the skeleton was borrowed,
+	the implementation is different. Particularly:
+
+	--- The WRR algorithm is different. Our version looks more
+	reasonable (I hope) and works when quanta are allowed to be
+	less than MTU, which is always the case when real time classes
+	have small rates. Note, that the statement of [3] is
+	incomplete, delay may actually be estimated even if class
+	per-round allotment is less than MTU. Namely, if per-round
+	allotment is W*r_i, and r_1+...+r_k = r < 1
+
+	delay_i <= ([MTU/(W*r_i)]*W*r + W*r + k*MTU)/B
+
+	In the worst case we have IntServ estimate with D = W*r+k*MTU
+	and C = MTU*r. The proof (if correct at all) is trivial.
+
+
+	--- It seems that cbq-2.0 is not very accurate. At least, I cannot
+	interpret some places, which look like wrong translations
+	from NS. Anyone is advised to find these differences
+	and explain to me, why I am wrong 8).
+
+	--- Linux has no EOI event, so that we cannot estimate true class
+	idle time. Workaround is to consider the next dequeue event
+	as sign that previous packet is finished. This is wrong because of
+	internal device queueing, but on a permanently loaded link it is true.
+	Moreover, combined with clock integrator, this scheme looks
+	very close to an ideal solution.  */
+
+struct cbq_sched_data;
+
+
+struct cbq_class {
+	struct Qdisc_class_common common;
+	struct cbq_class	*next_alive;	/* next class with backlog in this priority band */
+
+/* Parameters */
+	unsigned char		priority;	/* class priority */
+	unsigned char		priority2;	/* priority to be used after overlimit */
+	unsigned char		ewma_log;	/* time constant for idle time calculation */
+
+	u32			defmap;
+
+	/* Link-sharing scheduler parameters */
+	long			maxidle;	/* Class parameters: see below. */
+	long			offtime;
+	long			minidle;
+	u32			avpkt;
+	struct qdisc_rate_table	*R_tab;
+
+	/* General scheduler (WRR) parameters */
+	long			allot;
+	long			quantum;	/* Allotment per WRR round */
+	long			weight;		/* Relative allotment: see below */
+
+	struct Qdisc		*qdisc;		/* Ptr to CBQ discipline */
+	struct cbq_class	*split;		/* Ptr to split node */
+	struct cbq_class	*share;		/* Ptr to LS parent in the class tree */
+	struct cbq_class	*tparent;	/* Ptr to tree parent in the class tree */
+	struct cbq_class	*borrow;	/* NULL if class is bandwidth limited;
+						   parent otherwise */
+	struct cbq_class	*sibling;	/* Sibling chain */
+	struct cbq_class	*children;	/* Pointer to children chain */
+
+	struct Qdisc		*q;		/* Elementary queueing discipline */
+
+
+/* Variables */
+	unsigned char		cpriority;	/* Effective priority */
+	unsigned char		delayed;
+	unsigned char		level;		/* level of the class in hierarchy:
+						   0 for leaf classes, and maximal
+						   level of children + 1 for nodes.
+						 */
+
+	psched_time_t		last;		/* Last end of service */
+	psched_time_t		undertime;
+	long			avgidle;
+	long			deficit;	/* Saved deficit for WRR */
+	psched_time_t		penalized;
+	struct gnet_stats_basic_packed bstats;
+	struct gnet_stats_queue qstats;
+	struct net_rate_estimator __rcu *rate_est;
+	struct tc_cbq_xstats	xstats;
+
+	struct tcf_proto __rcu	*filter_list;
+	struct tcf_block	*block;
+
+	int			filters;
+
+	struct cbq_class	*defaults[TC_PRIO_MAX + 1];
+};
+
+struct cbq_sched_data {
+	struct Qdisc_class_hash	clhash;			/* Hash table of all classes */
+	int			nclasses[TC_CBQ_MAXPRIO + 1];
+	unsigned int		quanta[TC_CBQ_MAXPRIO + 1];
+
+	struct cbq_class	link;
+
+	unsigned int		activemask;
+	struct cbq_class	*active[TC_CBQ_MAXPRIO + 1];	/* List of all classes
+								   with backlog */
+
+#ifdef CONFIG_NET_CLS_ACT
+	struct cbq_class	*rx_class;
+#endif
+	struct cbq_class	*tx_class;
+	struct cbq_class	*tx_borrowed;
+	int			tx_len;
+	psched_time_t		now;		/* Cached timestamp */
+	unsigned int		pmask;
+
+	struct hrtimer		delay_timer;
+	struct qdisc_watchdog	watchdog;	/* Watchdog timer,
+						   started when CBQ has
+						   backlog, but cannot
+						   transmit just now */
+	psched_tdiff_t		wd_expires;
+	int			toplevel;
+	u32			hgenerator;
+};
+
+
+#define L2T(cl, len)	qdisc_l2t((cl)->R_tab, len)
+
+static inline struct cbq_class *
+cbq_class_lookup(struct cbq_sched_data *q, u32 classid)
+{
+	struct Qdisc_class_common *clc;
+
+	clc = qdisc_class_find(&q->clhash, classid);
+	if (clc == NULL)
+		return NULL;
+	return container_of(clc, struct cbq_class, common);
+}
+
+#ifdef CONFIG_NET_CLS_ACT
+
+static struct cbq_class *
+cbq_reclassify(struct sk_buff *skb, struct cbq_class *this)
+{
+	struct cbq_class *cl;
+
+	for (cl = this->tparent; cl; cl = cl->tparent) {
+		struct cbq_class *new = cl->defaults[TC_PRIO_BESTEFFORT];
+
+		if (new != NULL && new != this)
+			return new;
+	}
+	return NULL;
+}
+
+#endif
+
+/* Classify packet. The procedure is pretty complicated, but
+ * it allows us to combine link sharing and priority scheduling
+ * transparently.
+ *
+ * Namely, you can put link sharing rules (f.e. route based) at root of CBQ,
+ * so that it resolves to split nodes. Then packets are classified
+ * by logical priority, or a more specific classifier may be attached
+ * to the split node.
+ */
+
+static struct cbq_class *
+cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *head = &q->link;
+	struct cbq_class **defmap;
+	struct cbq_class *cl = NULL;
+	u32 prio = skb->priority;
+	struct tcf_proto *fl;
+	struct tcf_result res;
+
+	/*
+	 *  Step 1. If skb->priority points to one of our classes, use it.
+	 */
+	if (TC_H_MAJ(prio ^ sch->handle) == 0 &&
+	    (cl = cbq_class_lookup(q, prio)) != NULL)
+		return cl;
+
+	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
+	for (;;) {
+		int result = 0;
+		defmap = head->defaults;
+
+		fl = rcu_dereference_bh(head->filter_list);
+		/*
+		 * Step 2+n. Apply classifier.
+		 */
+		result = tcf_classify(skb, fl, &res, true);
+		if (!fl || result < 0)
+			goto fallback;
+
+		cl = (void *)res.class;
+		if (!cl) {
+			if (TC_H_MAJ(res.classid))
+				cl = cbq_class_lookup(q, res.classid);
+			else if ((cl = defmap[res.classid & TC_PRIO_MAX]) == NULL)
+				cl = defmap[TC_PRIO_BESTEFFORT];
+
+			if (cl == NULL)
+				goto fallback;
+		}
+		if (cl->level >= head->level)
+			goto fallback;
+#ifdef CONFIG_NET_CLS_ACT
+		switch (result) {
+		case TC_ACT_QUEUED:
+		case TC_ACT_STOLEN:
+		case TC_ACT_TRAP:
+			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
+			/* fall through */
+		case TC_ACT_SHOT:
+			return NULL;
+		case TC_ACT_RECLASSIFY:
+			return cbq_reclassify(skb, cl);
+		}
+#endif
+		if (cl->level == 0)
+			return cl;
+
+		/*
+		 * Step 3+n. If classifier selected a link sharing class,
+		 *	   apply agency specific classifier.
+		 *	   Repeat this procdure until we hit a leaf node.
+		 */
+		head = cl;
+	}
+
+fallback:
+	cl = head;
+
+	/*
+	 * Step 4. No success...
+	 */
+	if (TC_H_MAJ(prio) == 0 &&
+	    !(cl = head->defaults[prio & TC_PRIO_MAX]) &&
+	    !(cl = head->defaults[TC_PRIO_BESTEFFORT]))
+		return head;
+
+	return cl;
+}
+
+/*
+ * A packet has just been enqueued on the empty class.
+ * cbq_activate_class adds it to the tail of active class list
+ * of its priority band.
+ */
+
+static inline void cbq_activate_class(struct cbq_class *cl)
+{
+	struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
+	int prio = cl->cpriority;
+	struct cbq_class *cl_tail;
+
+	cl_tail = q->active[prio];
+	q->active[prio] = cl;
+
+	if (cl_tail != NULL) {
+		cl->next_alive = cl_tail->next_alive;
+		cl_tail->next_alive = cl;
+	} else {
+		cl->next_alive = cl;
+		q->activemask |= (1<<prio);
+	}
+}
+
+/*
+ * Unlink class from active chain.
+ * Note that this same procedure is done directly in cbq_dequeue*
+ * during round-robin procedure.
+ */
+
+static void cbq_deactivate_class(struct cbq_class *this)
+{
+	struct cbq_sched_data *q = qdisc_priv(this->qdisc);
+	int prio = this->cpriority;
+	struct cbq_class *cl;
+	struct cbq_class *cl_prev = q->active[prio];
+
+	do {
+		cl = cl_prev->next_alive;
+		if (cl == this) {
+			cl_prev->next_alive = cl->next_alive;
+			cl->next_alive = NULL;
+
+			if (cl == q->active[prio]) {
+				q->active[prio] = cl_prev;
+				if (cl == q->active[prio]) {
+					q->active[prio] = NULL;
+					q->activemask &= ~(1<<prio);
+					return;
+				}
+			}
+			return;
+		}
+	} while ((cl_prev = cl) != q->active[prio]);
+}
+
+static void
+cbq_mark_toplevel(struct cbq_sched_data *q, struct cbq_class *cl)
+{
+	int toplevel = q->toplevel;
+
+	if (toplevel > cl->level) {
+		psched_time_t now = psched_get_time();
+
+		do {
+			if (cl->undertime < now) {
+				q->toplevel = cl->level;
+				return;
+			}
+		} while ((cl = cl->borrow) != NULL && toplevel > cl->level);
+	}
+}
+
+static int
+cbq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
+	    struct sk_buff **to_free)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	int uninitialized_var(ret);
+	struct cbq_class *cl = cbq_classify(skb, sch, &ret);
+
+#ifdef CONFIG_NET_CLS_ACT
+	q->rx_class = cl;
+#endif
+	if (cl == NULL) {
+		if (ret & __NET_XMIT_BYPASS)
+			qdisc_qstats_drop(sch);
+		__qdisc_drop(skb, to_free);
+		return ret;
+	}
+
+	ret = qdisc_enqueue(skb, cl->q, to_free);
+	if (ret == NET_XMIT_SUCCESS) {
+		sch->q.qlen++;
+		cbq_mark_toplevel(q, cl);
+		if (!cl->next_alive)
+			cbq_activate_class(cl);
+		return ret;
+	}
+
+	if (net_xmit_drop_count(ret)) {
+		qdisc_qstats_drop(sch);
+		cbq_mark_toplevel(q, cl);
+		cl->qstats.drops++;
+	}
+	return ret;
+}
+
+/* Overlimit action: penalize leaf class by adding offtime */
+static void cbq_overlimit(struct cbq_class *cl)
+{
+	struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
+	psched_tdiff_t delay = cl->undertime - q->now;
+
+	if (!cl->delayed) {
+		delay += cl->offtime;
+
+		/*
+		 * Class goes to sleep, so that it will have no
+		 * chance to work avgidle. Let's forgive it 8)
+		 *
+		 * BTW cbq-2.0 has a crap in this
+		 * place, apparently they forgot to shift it by cl->ewma_log.
+		 */
+		if (cl->avgidle < 0)
+			delay -= (-cl->avgidle) - ((-cl->avgidle) >> cl->ewma_log);
+		if (cl->avgidle < cl->minidle)
+			cl->avgidle = cl->minidle;
+		if (delay <= 0)
+			delay = 1;
+		cl->undertime = q->now + delay;
+
+		cl->xstats.overactions++;
+		cl->delayed = 1;
+	}
+	if (q->wd_expires == 0 || q->wd_expires > delay)
+		q->wd_expires = delay;
+
+	/* Dirty work! We must schedule wakeups based on
+	 * real available rate, rather than leaf rate,
+	 * which may be tiny (even zero).
+	 */
+	if (q->toplevel == TC_CBQ_MAXLEVEL) {
+		struct cbq_class *b;
+		psched_tdiff_t base_delay = q->wd_expires;
+
+		for (b = cl->borrow; b; b = b->borrow) {
+			delay = b->undertime - q->now;
+			if (delay < base_delay) {
+				if (delay <= 0)
+					delay = 1;
+				base_delay = delay;
+			}
+		}
+
+		q->wd_expires = base_delay;
+	}
+}
+
+static psched_tdiff_t cbq_undelay_prio(struct cbq_sched_data *q, int prio,
+				       psched_time_t now)
+{
+	struct cbq_class *cl;
+	struct cbq_class *cl_prev = q->active[prio];
+	psched_time_t sched = now;
+
+	if (cl_prev == NULL)
+		return 0;
+
+	do {
+		cl = cl_prev->next_alive;
+		if (now - cl->penalized > 0) {
+			cl_prev->next_alive = cl->next_alive;
+			cl->next_alive = NULL;
+			cl->cpriority = cl->priority;
+			cl->delayed = 0;
+			cbq_activate_class(cl);
+
+			if (cl == q->active[prio]) {
+				q->active[prio] = cl_prev;
+				if (cl == q->active[prio]) {
+					q->active[prio] = NULL;
+					return 0;
+				}
+			}
+
+			cl = cl_prev->next_alive;
+		} else if (sched - cl->penalized > 0)
+			sched = cl->penalized;
+	} while ((cl_prev = cl) != q->active[prio]);
+
+	return sched - now;
+}
+
+static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
+{
+	struct cbq_sched_data *q = container_of(timer, struct cbq_sched_data,
+						delay_timer);
+	struct Qdisc *sch = q->watchdog.qdisc;
+	psched_time_t now;
+	psched_tdiff_t delay = 0;
+	unsigned int pmask;
+
+	now = psched_get_time();
+
+	pmask = q->pmask;
+	q->pmask = 0;
+
+	while (pmask) {
+		int prio = ffz(~pmask);
+		psched_tdiff_t tmp;
+
+		pmask &= ~(1<<prio);
+
+		tmp = cbq_undelay_prio(q, prio, now);
+		if (tmp > 0) {
+			q->pmask |= 1<<prio;
+			if (tmp < delay || delay == 0)
+				delay = tmp;
+		}
+	}
+
+	if (delay) {
+		ktime_t time;
+
+		time = 0;
+		time = ktime_add_ns(time, PSCHED_TICKS2NS(now + delay));
+		hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS_PINNED);
+	}
+
+	__netif_schedule(qdisc_root(sch));
+	return HRTIMER_NORESTART;
+}
+
+/*
+ * It is mission critical procedure.
+ *
+ * We "regenerate" toplevel cutoff, if transmitting class
+ * has backlog and it is not regulated. It is not part of
+ * original CBQ description, but looks more reasonable.
+ * Probably, it is wrong. This question needs further investigation.
+ */
+
+static inline void
+cbq_update_toplevel(struct cbq_sched_data *q, struct cbq_class *cl,
+		    struct cbq_class *borrowed)
+{
+	if (cl && q->toplevel >= borrowed->level) {
+		if (cl->q->q.qlen > 1) {
+			do {
+				if (borrowed->undertime == PSCHED_PASTPERFECT) {
+					q->toplevel = borrowed->level;
+					return;
+				}
+			} while ((borrowed = borrowed->borrow) != NULL);
+		}
+#if 0
+	/* It is not necessary now. Uncommenting it
+	   will save CPU cycles, but decrease fairness.
+	 */
+		q->toplevel = TC_CBQ_MAXLEVEL;
+#endif
+	}
+}
+
+static void
+cbq_update(struct cbq_sched_data *q)
+{
+	struct cbq_class *this = q->tx_class;
+	struct cbq_class *cl = this;
+	int len = q->tx_len;
+	psched_time_t now;
+
+	q->tx_class = NULL;
+	/* Time integrator. We calculate EOS time
+	 * by adding expected packet transmission time.
+	 */
+	now = q->now + L2T(&q->link, len);
+
+	for ( ; cl; cl = cl->share) {
+		long avgidle = cl->avgidle;
+		long idle;
+
+		cl->bstats.packets++;
+		cl->bstats.bytes += len;
+
+		/*
+		 * (now - last) is total time between packet right edges.
+		 * (last_pktlen/rate) is "virtual" busy time, so that
+		 *
+		 *	idle = (now - last) - last_pktlen/rate
+		 */
+
+		idle = now - cl->last;
+		if ((unsigned long)idle > 128*1024*1024) {
+			avgidle = cl->maxidle;
+		} else {
+			idle -= L2T(cl, len);
+
+		/* true_avgidle := (1-W)*true_avgidle + W*idle,
+		 * where W=2^{-ewma_log}. But cl->avgidle is scaled:
+		 * cl->avgidle == true_avgidle/W,
+		 * hence:
+		 */
+			avgidle += idle - (avgidle>>cl->ewma_log);
+		}
+
+		if (avgidle <= 0) {
+			/* Overlimit or at-limit */
+
+			if (avgidle < cl->minidle)
+				avgidle = cl->minidle;
+
+			cl->avgidle = avgidle;
+
+			/* Calculate expected time, when this class
+			 * will be allowed to send.
+			 * It will occur, when:
+			 * (1-W)*true_avgidle + W*delay = 0, i.e.
+			 * idle = (1/W - 1)*(-true_avgidle)
+			 * or
+			 * idle = (1 - W)*(-cl->avgidle);
+			 */
+			idle = (-avgidle) - ((-avgidle) >> cl->ewma_log);
+
+			/*
+			 * That is not all.
+			 * To maintain the rate allocated to the class,
+			 * we add to undertime virtual clock,
+			 * necessary to complete transmitted packet.
+			 * (len/phys_bandwidth has been already passed
+			 * to the moment of cbq_update)
+			 */
+
+			idle -= L2T(&q->link, len);
+			idle += L2T(cl, len);
+
+			cl->undertime = now + idle;
+		} else {
+			/* Underlimit */
+
+			cl->undertime = PSCHED_PASTPERFECT;
+			if (avgidle > cl->maxidle)
+				cl->avgidle = cl->maxidle;
+			else
+				cl->avgidle = avgidle;
+		}
+		if ((s64)(now - cl->last) > 0)
+			cl->last = now;
+	}
+
+	cbq_update_toplevel(q, this, q->tx_borrowed);
+}
+
+static inline struct cbq_class *
+cbq_under_limit(struct cbq_class *cl)
+{
+	struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
+	struct cbq_class *this_cl = cl;
+
+	if (cl->tparent == NULL)
+		return cl;
+
+	if (cl->undertime == PSCHED_PASTPERFECT || q->now >= cl->undertime) {
+		cl->delayed = 0;
+		return cl;
+	}
+
+	do {
+		/* It is very suspicious place. Now overlimit
+		 * action is generated for not bounded classes
+		 * only if link is completely congested.
+		 * Though it is in agree with ancestor-only paradigm,
+		 * it looks very stupid. Particularly,
+		 * it means that this chunk of code will either
+		 * never be called or result in strong amplification
+		 * of burstiness. Dangerous, silly, and, however,
+		 * no another solution exists.
+		 */
+		cl = cl->borrow;
+		if (!cl) {
+			this_cl->qstats.overlimits++;
+			cbq_overlimit(this_cl);
+			return NULL;
+		}
+		if (cl->level > q->toplevel)
+			return NULL;
+	} while (cl->undertime != PSCHED_PASTPERFECT && q->now < cl->undertime);
+
+	cl->delayed = 0;
+	return cl;
+}
+
+static inline struct sk_buff *
+cbq_dequeue_prio(struct Qdisc *sch, int prio)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl_tail, *cl_prev, *cl;
+	struct sk_buff *skb;
+	int deficit;
+
+	cl_tail = cl_prev = q->active[prio];
+	cl = cl_prev->next_alive;
+
+	do {
+		deficit = 0;
+
+		/* Start round */
+		do {
+			struct cbq_class *borrow = cl;
+
+			if (cl->q->q.qlen &&
+			    (borrow = cbq_under_limit(cl)) == NULL)
+				goto skip_class;
+
+			if (cl->deficit <= 0) {
+				/* Class exhausted its allotment per
+				 * this round. Switch to the next one.
+				 */
+				deficit = 1;
+				cl->deficit += cl->quantum;
+				goto next_class;
+			}
+
+			skb = cl->q->dequeue(cl->q);
+
+			/* Class did not give us any skb :-(
+			 * It could occur even if cl->q->q.qlen != 0
+			 * f.e. if cl->q == "tbf"
+			 */
+			if (skb == NULL)
+				goto skip_class;
+
+			cl->deficit -= qdisc_pkt_len(skb);
+			q->tx_class = cl;
+			q->tx_borrowed = borrow;
+			if (borrow != cl) {
+#ifndef CBQ_XSTATS_BORROWS_BYTES
+				borrow->xstats.borrows++;
+				cl->xstats.borrows++;
+#else
+				borrow->xstats.borrows += qdisc_pkt_len(skb);
+				cl->xstats.borrows += qdisc_pkt_len(skb);
+#endif
+			}
+			q->tx_len = qdisc_pkt_len(skb);
+
+			if (cl->deficit <= 0) {
+				q->active[prio] = cl;
+				cl = cl->next_alive;
+				cl->deficit += cl->quantum;
+			}
+			return skb;
+
+skip_class:
+			if (cl->q->q.qlen == 0 || prio != cl->cpriority) {
+				/* Class is empty or penalized.
+				 * Unlink it from active chain.
+				 */
+				cl_prev->next_alive = cl->next_alive;
+				cl->next_alive = NULL;
+
+				/* Did cl_tail point to it? */
+				if (cl == cl_tail) {
+					/* Repair it! */
+					cl_tail = cl_prev;
+
+					/* Was it the last class in this band? */
+					if (cl == cl_tail) {
+						/* Kill the band! */
+						q->active[prio] = NULL;
+						q->activemask &= ~(1<<prio);
+						if (cl->q->q.qlen)
+							cbq_activate_class(cl);
+						return NULL;
+					}
+
+					q->active[prio] = cl_tail;
+				}
+				if (cl->q->q.qlen)
+					cbq_activate_class(cl);
+
+				cl = cl_prev;
+			}
+
+next_class:
+			cl_prev = cl;
+			cl = cl->next_alive;
+		} while (cl_prev != cl_tail);
+	} while (deficit);
+
+	q->active[prio] = cl_prev;
+
+	return NULL;
+}
+
+static inline struct sk_buff *
+cbq_dequeue_1(struct Qdisc *sch)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct sk_buff *skb;
+	unsigned int activemask;
+
+	activemask = q->activemask & 0xFF;
+	while (activemask) {
+		int prio = ffz(~activemask);
+		activemask &= ~(1<<prio);
+		skb = cbq_dequeue_prio(sch, prio);
+		if (skb)
+			return skb;
+	}
+	return NULL;
+}
+
+static struct sk_buff *
+cbq_dequeue(struct Qdisc *sch)
+{
+	struct sk_buff *skb;
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	psched_time_t now;
+
+	now = psched_get_time();
+
+	if (q->tx_class)
+		cbq_update(q);
+
+	q->now = now;
+
+	for (;;) {
+		q->wd_expires = 0;
+
+		skb = cbq_dequeue_1(sch);
+		if (skb) {
+			qdisc_bstats_update(sch, skb);
+			sch->q.qlen--;
+			return skb;
+		}
+
+		/* All the classes are overlimit.
+		 *
+		 * It is possible, if:
+		 *
+		 * 1. Scheduler is empty.
+		 * 2. Toplevel cutoff inhibited borrowing.
+		 * 3. Root class is overlimit.
+		 *
+		 * Reset 2d and 3d conditions and retry.
+		 *
+		 * Note, that NS and cbq-2.0 are buggy, peeking
+		 * an arbitrary class is appropriate for ancestor-only
+		 * sharing, but not for toplevel algorithm.
+		 *
+		 * Our version is better, but slower, because it requires
+		 * two passes, but it is unavoidable with top-level sharing.
+		 */
+
+		if (q->toplevel == TC_CBQ_MAXLEVEL &&
+		    q->link.undertime == PSCHED_PASTPERFECT)
+			break;
+
+		q->toplevel = TC_CBQ_MAXLEVEL;
+		q->link.undertime = PSCHED_PASTPERFECT;
+	}
+
+	/* No packets in scheduler or nobody wants to give them to us :-(
+	 * Sigh... start watchdog timer in the last case.
+	 */
+
+	if (sch->q.qlen) {
+		qdisc_qstats_overlimit(sch);
+		if (q->wd_expires)
+			qdisc_watchdog_schedule(&q->watchdog,
+						now + q->wd_expires);
+	}
+	return NULL;
+}
+
+/* CBQ class maintanance routines */
+
+static void cbq_adjust_levels(struct cbq_class *this)
+{
+	if (this == NULL)
+		return;
+
+	do {
+		int level = 0;
+		struct cbq_class *cl;
+
+		cl = this->children;
+		if (cl) {
+			do {
+				if (cl->level > level)
+					level = cl->level;
+			} while ((cl = cl->sibling) != this->children);
+		}
+		this->level = level + 1;
+	} while ((this = this->tparent) != NULL);
+}
+
+static void cbq_normalize_quanta(struct cbq_sched_data *q, int prio)
+{
+	struct cbq_class *cl;
+	unsigned int h;
+
+	if (q->quanta[prio] == 0)
+		return;
+
+	for (h = 0; h < q->clhash.hashsize; h++) {
+		hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
+			/* BUGGGG... Beware! This expression suffer of
+			 * arithmetic overflows!
+			 */
+			if (cl->priority == prio) {
+				cl->quantum = (cl->weight*cl->allot*q->nclasses[prio])/
+					q->quanta[prio];
+			}
+			if (cl->quantum <= 0 ||
+			    cl->quantum > 32*qdisc_dev(cl->qdisc)->mtu) {
+				pr_warn("CBQ: class %08x has bad quantum==%ld, repaired.\n",
+					cl->common.classid, cl->quantum);
+				cl->quantum = qdisc_dev(cl->qdisc)->mtu/2 + 1;
+			}
+		}
+	}
+}
+
+static void cbq_sync_defmap(struct cbq_class *cl)
+{
+	struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
+	struct cbq_class *split = cl->split;
+	unsigned int h;
+	int i;
+
+	if (split == NULL)
+		return;
+
+	for (i = 0; i <= TC_PRIO_MAX; i++) {
+		if (split->defaults[i] == cl && !(cl->defmap & (1<<i)))
+			split->defaults[i] = NULL;
+	}
+
+	for (i = 0; i <= TC_PRIO_MAX; i++) {
+		int level = split->level;
+
+		if (split->defaults[i])
+			continue;
+
+		for (h = 0; h < q->clhash.hashsize; h++) {
+			struct cbq_class *c;
+
+			hlist_for_each_entry(c, &q->clhash.hash[h],
+					     common.hnode) {
+				if (c->split == split && c->level < level &&
+				    c->defmap & (1<<i)) {
+					split->defaults[i] = c;
+					level = c->level;
+				}
+			}
+		}
+	}
+}
+
+static void cbq_change_defmap(struct cbq_class *cl, u32 splitid, u32 def, u32 mask)
+{
+	struct cbq_class *split = NULL;
+
+	if (splitid == 0) {
+		split = cl->split;
+		if (!split)
+			return;
+		splitid = split->common.classid;
+	}
+
+	if (split == NULL || split->common.classid != splitid) {
+		for (split = cl->tparent; split; split = split->tparent)
+			if (split->common.classid == splitid)
+				break;
+	}
+
+	if (split == NULL)
+		return;
+
+	if (cl->split != split) {
+		cl->defmap = 0;
+		cbq_sync_defmap(cl);
+		cl->split = split;
+		cl->defmap = def & mask;
+	} else
+		cl->defmap = (cl->defmap & ~mask) | (def & mask);
+
+	cbq_sync_defmap(cl);
+}
+
+static void cbq_unlink_class(struct cbq_class *this)
+{
+	struct cbq_class *cl, **clp;
+	struct cbq_sched_data *q = qdisc_priv(this->qdisc);
+
+	qdisc_class_hash_remove(&q->clhash, &this->common);
+
+	if (this->tparent) {
+		clp = &this->sibling;
+		cl = *clp;
+		do {
+			if (cl == this) {
+				*clp = cl->sibling;
+				break;
+			}
+			clp = &cl->sibling;
+		} while ((cl = *clp) != this->sibling);
+
+		if (this->tparent->children == this) {
+			this->tparent->children = this->sibling;
+			if (this->sibling == this)
+				this->tparent->children = NULL;
+		}
+	} else {
+		WARN_ON(this->sibling != this);
+	}
+}
+
+static void cbq_link_class(struct cbq_class *this)
+{
+	struct cbq_sched_data *q = qdisc_priv(this->qdisc);
+	struct cbq_class *parent = this->tparent;
+
+	this->sibling = this;
+	qdisc_class_hash_insert(&q->clhash, &this->common);
+
+	if (parent == NULL)
+		return;
+
+	if (parent->children == NULL) {
+		parent->children = this;
+	} else {
+		this->sibling = parent->children->sibling;
+		parent->children->sibling = this;
+	}
+}
+
+static void
+cbq_reset(struct Qdisc *sch)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl;
+	int prio;
+	unsigned int h;
+
+	q->activemask = 0;
+	q->pmask = 0;
+	q->tx_class = NULL;
+	q->tx_borrowed = NULL;
+	qdisc_watchdog_cancel(&q->watchdog);
+	hrtimer_cancel(&q->delay_timer);
+	q->toplevel = TC_CBQ_MAXLEVEL;
+	q->now = psched_get_time();
+
+	for (prio = 0; prio <= TC_CBQ_MAXPRIO; prio++)
+		q->active[prio] = NULL;
+
+	for (h = 0; h < q->clhash.hashsize; h++) {
+		hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
+			qdisc_reset(cl->q);
+
+			cl->next_alive = NULL;
+			cl->undertime = PSCHED_PASTPERFECT;
+			cl->avgidle = cl->maxidle;
+			cl->deficit = cl->quantum;
+			cl->cpriority = cl->priority;
+		}
+	}
+	sch->q.qlen = 0;
+}
+
+
+static int cbq_set_lss(struct cbq_class *cl, struct tc_cbq_lssopt *lss)
+{
+	if (lss->change & TCF_CBQ_LSS_FLAGS) {
+		cl->share = (lss->flags & TCF_CBQ_LSS_ISOLATED) ? NULL : cl->tparent;
+		cl->borrow = (lss->flags & TCF_CBQ_LSS_BOUNDED) ? NULL : cl->tparent;
+	}
+	if (lss->change & TCF_CBQ_LSS_EWMA)
+		cl->ewma_log = lss->ewma_log;
+	if (lss->change & TCF_CBQ_LSS_AVPKT)
+		cl->avpkt = lss->avpkt;
+	if (lss->change & TCF_CBQ_LSS_MINIDLE)
+		cl->minidle = -(long)lss->minidle;
+	if (lss->change & TCF_CBQ_LSS_MAXIDLE) {
+		cl->maxidle = lss->maxidle;
+		cl->avgidle = lss->maxidle;
+	}
+	if (lss->change & TCF_CBQ_LSS_OFFTIME)
+		cl->offtime = lss->offtime;
+	return 0;
+}
+
+static void cbq_rmprio(struct cbq_sched_data *q, struct cbq_class *cl)
+{
+	q->nclasses[cl->priority]--;
+	q->quanta[cl->priority] -= cl->weight;
+	cbq_normalize_quanta(q, cl->priority);
+}
+
+static void cbq_addprio(struct cbq_sched_data *q, struct cbq_class *cl)
+{
+	q->nclasses[cl->priority]++;
+	q->quanta[cl->priority] += cl->weight;
+	cbq_normalize_quanta(q, cl->priority);
+}
+
+static int cbq_set_wrr(struct cbq_class *cl, struct tc_cbq_wrropt *wrr)
+{
+	struct cbq_sched_data *q = qdisc_priv(cl->qdisc);
+
+	if (wrr->allot)
+		cl->allot = wrr->allot;
+	if (wrr->weight)
+		cl->weight = wrr->weight;
+	if (wrr->priority) {
+		cl->priority = wrr->priority - 1;
+		cl->cpriority = cl->priority;
+		if (cl->priority >= cl->priority2)
+			cl->priority2 = TC_CBQ_MAXPRIO - 1;
+	}
+
+	cbq_addprio(q, cl);
+	return 0;
+}
+
+static int cbq_set_fopt(struct cbq_class *cl, struct tc_cbq_fopt *fopt)
+{
+	cbq_change_defmap(cl, fopt->split, fopt->defmap, fopt->defchange);
+	return 0;
+}
+
+static const struct nla_policy cbq_policy[TCA_CBQ_MAX + 1] = {
+	[TCA_CBQ_LSSOPT]	= { .len = sizeof(struct tc_cbq_lssopt) },
+	[TCA_CBQ_WRROPT]	= { .len = sizeof(struct tc_cbq_wrropt) },
+	[TCA_CBQ_FOPT]		= { .len = sizeof(struct tc_cbq_fopt) },
+	[TCA_CBQ_OVL_STRATEGY]	= { .len = sizeof(struct tc_cbq_ovl) },
+	[TCA_CBQ_RATE]		= { .len = sizeof(struct tc_ratespec) },
+	[TCA_CBQ_RTAB]		= { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
+	[TCA_CBQ_POLICE]	= { .len = sizeof(struct tc_cbq_police) },
+};
+
+static int cbq_opt_parse(struct nlattr *tb[TCA_CBQ_MAX + 1],
+			 struct nlattr *opt,
+			 struct netlink_ext_ack *extack)
+{
+	int err;
+
+	if (!opt) {
+		NL_SET_ERR_MSG(extack, "CBQ options are required for this operation");
+		return -EINVAL;
+	}
+
+	err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy, extack);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_CBQ_WRROPT]) {
+		const struct tc_cbq_wrropt *wrr = nla_data(tb[TCA_CBQ_WRROPT]);
+
+		if (wrr->priority > TC_CBQ_MAXPRIO) {
+			NL_SET_ERR_MSG(extack, "priority is bigger than TC_CBQ_MAXPRIO");
+			err = -EINVAL;
+		}
+	}
+	return err;
+}
+
+static int cbq_init(struct Qdisc *sch, struct nlattr *opt,
+		    struct netlink_ext_ack *extack)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct nlattr *tb[TCA_CBQ_MAX + 1];
+	struct tc_ratespec *r;
+	int err;
+
+	qdisc_watchdog_init(&q->watchdog, sch);
+	hrtimer_init(&q->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+	q->delay_timer.function = cbq_undelay;
+
+	err = cbq_opt_parse(tb, opt, extack);
+	if (err < 0)
+		return err;
+
+	if (!tb[TCA_CBQ_RTAB] || !tb[TCA_CBQ_RATE]) {
+		NL_SET_ERR_MSG(extack, "Rate specification missing or incomplete");
+		return -EINVAL;
+	}
+
+	r = nla_data(tb[TCA_CBQ_RATE]);
+
+	q->link.R_tab = qdisc_get_rtab(r, tb[TCA_CBQ_RTAB], extack);
+	if (!q->link.R_tab)
+		return -EINVAL;
+
+	err = tcf_block_get(&q->link.block, &q->link.filter_list, sch, extack);
+	if (err)
+		goto put_rtab;
+
+	err = qdisc_class_hash_init(&q->clhash);
+	if (err < 0)
+		goto put_block;
+
+	q->link.sibling = &q->link;
+	q->link.common.classid = sch->handle;
+	q->link.qdisc = sch;
+	q->link.q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
+				      sch->handle, NULL);
+	if (!q->link.q)
+		q->link.q = &noop_qdisc;
+	else
+		qdisc_hash_add(q->link.q, true);
+
+	q->link.priority = TC_CBQ_MAXPRIO - 1;
+	q->link.priority2 = TC_CBQ_MAXPRIO - 1;
+	q->link.cpriority = TC_CBQ_MAXPRIO - 1;
+	q->link.allot = psched_mtu(qdisc_dev(sch));
+	q->link.quantum = q->link.allot;
+	q->link.weight = q->link.R_tab->rate.rate;
+
+	q->link.ewma_log = TC_CBQ_DEF_EWMA;
+	q->link.avpkt = q->link.allot/2;
+	q->link.minidle = -0x7FFFFFFF;
+
+	q->toplevel = TC_CBQ_MAXLEVEL;
+	q->now = psched_get_time();
+
+	cbq_link_class(&q->link);
+
+	if (tb[TCA_CBQ_LSSOPT])
+		cbq_set_lss(&q->link, nla_data(tb[TCA_CBQ_LSSOPT]));
+
+	cbq_addprio(q, &q->link);
+	return 0;
+
+put_block:
+	tcf_block_put(q->link.block);
+
+put_rtab:
+	qdisc_put_rtab(q->link.R_tab);
+	return err;
+}
+
+static int cbq_dump_rate(struct sk_buff *skb, struct cbq_class *cl)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+
+	if (nla_put(skb, TCA_CBQ_RATE, sizeof(cl->R_tab->rate), &cl->R_tab->rate))
+		goto nla_put_failure;
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static int cbq_dump_lss(struct sk_buff *skb, struct cbq_class *cl)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tc_cbq_lssopt opt;
+
+	opt.flags = 0;
+	if (cl->borrow == NULL)
+		opt.flags |= TCF_CBQ_LSS_BOUNDED;
+	if (cl->share == NULL)
+		opt.flags |= TCF_CBQ_LSS_ISOLATED;
+	opt.ewma_log = cl->ewma_log;
+	opt.level = cl->level;
+	opt.avpkt = cl->avpkt;
+	opt.maxidle = cl->maxidle;
+	opt.minidle = (u32)(-cl->minidle);
+	opt.offtime = cl->offtime;
+	opt.change = ~0;
+	if (nla_put(skb, TCA_CBQ_LSSOPT, sizeof(opt), &opt))
+		goto nla_put_failure;
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static int cbq_dump_wrr(struct sk_buff *skb, struct cbq_class *cl)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tc_cbq_wrropt opt;
+
+	memset(&opt, 0, sizeof(opt));
+	opt.flags = 0;
+	opt.allot = cl->allot;
+	opt.priority = cl->priority + 1;
+	opt.cpriority = cl->cpriority + 1;
+	opt.weight = cl->weight;
+	if (nla_put(skb, TCA_CBQ_WRROPT, sizeof(opt), &opt))
+		goto nla_put_failure;
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static int cbq_dump_fopt(struct sk_buff *skb, struct cbq_class *cl)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tc_cbq_fopt opt;
+
+	if (cl->split || cl->defmap) {
+		opt.split = cl->split ? cl->split->common.classid : 0;
+		opt.defmap = cl->defmap;
+		opt.defchange = ~0;
+		if (nla_put(skb, TCA_CBQ_FOPT, sizeof(opt), &opt))
+			goto nla_put_failure;
+	}
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	return -1;
+}
+
+static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
+{
+	if (cbq_dump_lss(skb, cl) < 0 ||
+	    cbq_dump_rate(skb, cl) < 0 ||
+	    cbq_dump_wrr(skb, cl) < 0 ||
+	    cbq_dump_fopt(skb, cl) < 0)
+		return -1;
+	return 0;
+}
+
+static int cbq_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct nlattr *nest;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+	if (cbq_dump_attr(skb, &q->link) < 0)
+		goto nla_put_failure;
+	return nla_nest_end(skb, nest);
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return -1;
+}
+
+static int
+cbq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+
+	q->link.xstats.avgidle = q->link.avgidle;
+	return gnet_stats_copy_app(d, &q->link.xstats, sizeof(q->link.xstats));
+}
+
+static int
+cbq_dump_class(struct Qdisc *sch, unsigned long arg,
+	       struct sk_buff *skb, struct tcmsg *tcm)
+{
+	struct cbq_class *cl = (struct cbq_class *)arg;
+	struct nlattr *nest;
+
+	if (cl->tparent)
+		tcm->tcm_parent = cl->tparent->common.classid;
+	else
+		tcm->tcm_parent = TC_H_ROOT;
+	tcm->tcm_handle = cl->common.classid;
+	tcm->tcm_info = cl->q->handle;
+
+	nest = nla_nest_start(skb, TCA_OPTIONS);
+	if (nest == NULL)
+		goto nla_put_failure;
+	if (cbq_dump_attr(skb, cl) < 0)
+		goto nla_put_failure;
+	return nla_nest_end(skb, nest);
+
+nla_put_failure:
+	nla_nest_cancel(skb, nest);
+	return -1;
+}
+
+static int
+cbq_dump_class_stats(struct Qdisc *sch, unsigned long arg,
+	struct gnet_dump *d)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl = (struct cbq_class *)arg;
+
+	cl->xstats.avgidle = cl->avgidle;
+	cl->xstats.undertime = 0;
+
+	if (cl->undertime != PSCHED_PASTPERFECT)
+		cl->xstats.undertime = cl->undertime - q->now;
+
+	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->qstats, cl->q->q.qlen) < 0)
+		return -1;
+
+	return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
+}
+
+static int cbq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
+		     struct Qdisc **old, struct netlink_ext_ack *extack)
+{
+	struct cbq_class *cl = (struct cbq_class *)arg;
+
+	if (new == NULL) {
+		new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
+					cl->common.classid, extack);
+		if (new == NULL)
+			return -ENOBUFS;
+	}
+
+	*old = qdisc_replace(sch, new, &cl->q);
+	return 0;
+}
+
+static struct Qdisc *cbq_leaf(struct Qdisc *sch, unsigned long arg)
+{
+	struct cbq_class *cl = (struct cbq_class *)arg;
+
+	return cl->q;
+}
+
+static void cbq_qlen_notify(struct Qdisc *sch, unsigned long arg)
+{
+	struct cbq_class *cl = (struct cbq_class *)arg;
+
+	cbq_deactivate_class(cl);
+}
+
+static unsigned long cbq_find(struct Qdisc *sch, u32 classid)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+
+	return (unsigned long)cbq_class_lookup(q, classid);
+}
+
+static void cbq_destroy_class(struct Qdisc *sch, struct cbq_class *cl)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+
+	WARN_ON(cl->filters);
+
+	tcf_block_put(cl->block);
+	qdisc_put(cl->q);
+	qdisc_put_rtab(cl->R_tab);
+	gen_kill_estimator(&cl->rate_est);
+	if (cl != &q->link)
+		kfree(cl);
+}
+
+static void cbq_destroy(struct Qdisc *sch)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct hlist_node *next;
+	struct cbq_class *cl;
+	unsigned int h;
+
+#ifdef CONFIG_NET_CLS_ACT
+	q->rx_class = NULL;
+#endif
+	/*
+	 * Filters must be destroyed first because we don't destroy the
+	 * classes from root to leafs which means that filters can still
+	 * be bound to classes which have been destroyed already. --TGR '04
+	 */
+	for (h = 0; h < q->clhash.hashsize; h++) {
+		hlist_for_each_entry(cl, &q->clhash.hash[h], common.hnode) {
+			tcf_block_put(cl->block);
+			cl->block = NULL;
+		}
+	}
+	for (h = 0; h < q->clhash.hashsize; h++) {
+		hlist_for_each_entry_safe(cl, next, &q->clhash.hash[h],
+					  common.hnode)
+			cbq_destroy_class(sch, cl);
+	}
+	qdisc_class_hash_destroy(&q->clhash);
+}
+
+static int
+cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca,
+		 unsigned long *arg, struct netlink_ext_ack *extack)
+{
+	int err;
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl = (struct cbq_class *)*arg;
+	struct nlattr *opt = tca[TCA_OPTIONS];
+	struct nlattr *tb[TCA_CBQ_MAX + 1];
+	struct cbq_class *parent;
+	struct qdisc_rate_table *rtab = NULL;
+
+	err = cbq_opt_parse(tb, opt, extack);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_CBQ_OVL_STRATEGY] || tb[TCA_CBQ_POLICE]) {
+		NL_SET_ERR_MSG(extack, "Neither overlimit strategy nor policing attributes can be used for changing class params");
+		return -EOPNOTSUPP;
+	}
+
+	if (cl) {
+		/* Check parent */
+		if (parentid) {
+			if (cl->tparent &&
+			    cl->tparent->common.classid != parentid) {
+				NL_SET_ERR_MSG(extack, "Invalid parent id");
+				return -EINVAL;
+			}
+			if (!cl->tparent && parentid != TC_H_ROOT) {
+				NL_SET_ERR_MSG(extack, "Parent must be root");
+				return -EINVAL;
+			}
+		}
+
+		if (tb[TCA_CBQ_RATE]) {
+			rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]),
+					      tb[TCA_CBQ_RTAB], extack);
+			if (rtab == NULL)
+				return -EINVAL;
+		}
+
+		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) {
+				NL_SET_ERR_MSG(extack, "Failed to replace specified rate estimator");
+				qdisc_put_rtab(rtab);
+				return err;
+			}
+		}
+
+		/* Change class parameters */
+		sch_tree_lock(sch);
+
+		if (cl->next_alive != NULL)
+			cbq_deactivate_class(cl);
+
+		if (rtab) {
+			qdisc_put_rtab(cl->R_tab);
+			cl->R_tab = rtab;
+		}
+
+		if (tb[TCA_CBQ_LSSOPT])
+			cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
+
+		if (tb[TCA_CBQ_WRROPT]) {
+			cbq_rmprio(q, cl);
+			cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
+		}
+
+		if (tb[TCA_CBQ_FOPT])
+			cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
+
+		if (cl->q->q.qlen)
+			cbq_activate_class(cl);
+
+		sch_tree_unlock(sch);
+
+		return 0;
+	}
+
+	if (parentid == TC_H_ROOT)
+		return -EINVAL;
+
+	if (!tb[TCA_CBQ_WRROPT] || !tb[TCA_CBQ_RATE] || !tb[TCA_CBQ_LSSOPT]) {
+		NL_SET_ERR_MSG(extack, "One of the following attributes MUST be specified: WRR, rate or link sharing");
+		return -EINVAL;
+	}
+
+	rtab = qdisc_get_rtab(nla_data(tb[TCA_CBQ_RATE]), tb[TCA_CBQ_RTAB],
+			      extack);
+	if (rtab == NULL)
+		return -EINVAL;
+
+	if (classid) {
+		err = -EINVAL;
+		if (TC_H_MAJ(classid ^ sch->handle) ||
+		    cbq_class_lookup(q, classid)) {
+			NL_SET_ERR_MSG(extack, "Specified class not found");
+			goto failure;
+		}
+	} else {
+		int i;
+		classid = TC_H_MAKE(sch->handle, 0x8000);
+
+		for (i = 0; i < 0x8000; i++) {
+			if (++q->hgenerator >= 0x8000)
+				q->hgenerator = 1;
+			if (cbq_class_lookup(q, classid|q->hgenerator) == NULL)
+				break;
+		}
+		err = -ENOSR;
+		if (i >= 0x8000) {
+			NL_SET_ERR_MSG(extack, "Unable to generate classid");
+			goto failure;
+		}
+		classid = classid|q->hgenerator;
+	}
+
+	parent = &q->link;
+	if (parentid) {
+		parent = cbq_class_lookup(q, parentid);
+		err = -EINVAL;
+		if (!parent) {
+			NL_SET_ERR_MSG(extack, "Failed to find parentid");
+			goto failure;
+		}
+	}
+
+	err = -ENOBUFS;
+	cl = kzalloc(sizeof(*cl), GFP_KERNEL);
+	if (cl == NULL)
+		goto failure;
+
+	err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
+	if (err) {
+		kfree(cl);
+		goto failure;
+	}
+
+	if (tca[TCA_RATE]) {
+		err = gen_new_estimator(&cl->bstats, NULL, &cl->rate_est,
+					NULL,
+					qdisc_root_sleeping_running(sch),
+					tca[TCA_RATE]);
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Couldn't create new estimator");
+			tcf_block_put(cl->block);
+			kfree(cl);
+			goto failure;
+		}
+	}
+
+	cl->R_tab = rtab;
+	rtab = NULL;
+	cl->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid,
+				  NULL);
+	if (!cl->q)
+		cl->q = &noop_qdisc;
+	else
+		qdisc_hash_add(cl->q, true);
+
+	cl->common.classid = classid;
+	cl->tparent = parent;
+	cl->qdisc = sch;
+	cl->allot = parent->allot;
+	cl->quantum = cl->allot;
+	cl->weight = cl->R_tab->rate.rate;
+
+	sch_tree_lock(sch);
+	cbq_link_class(cl);
+	cl->borrow = cl->tparent;
+	if (cl->tparent != &q->link)
+		cl->share = cl->tparent;
+	cbq_adjust_levels(parent);
+	cl->minidle = -0x7FFFFFFF;
+	cbq_set_lss(cl, nla_data(tb[TCA_CBQ_LSSOPT]));
+	cbq_set_wrr(cl, nla_data(tb[TCA_CBQ_WRROPT]));
+	if (cl->ewma_log == 0)
+		cl->ewma_log = q->link.ewma_log;
+	if (cl->maxidle == 0)
+		cl->maxidle = q->link.maxidle;
+	if (cl->avpkt == 0)
+		cl->avpkt = q->link.avpkt;
+	if (tb[TCA_CBQ_FOPT])
+		cbq_set_fopt(cl, nla_data(tb[TCA_CBQ_FOPT]));
+	sch_tree_unlock(sch);
+
+	qdisc_class_hash_grow(sch, &q->clhash);
+
+	*arg = (unsigned long)cl;
+	return 0;
+
+failure:
+	qdisc_put_rtab(rtab);
+	return err;
+}
+
+static int cbq_delete(struct Qdisc *sch, unsigned long arg)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl = (struct cbq_class *)arg;
+	unsigned int qlen, backlog;
+
+	if (cl->filters || cl->children || cl == &q->link)
+		return -EBUSY;
+
+	sch_tree_lock(sch);
+
+	qlen = cl->q->q.qlen;
+	backlog = cl->q->qstats.backlog;
+	qdisc_reset(cl->q);
+	qdisc_tree_reduce_backlog(cl->q, qlen, backlog);
+
+	if (cl->next_alive)
+		cbq_deactivate_class(cl);
+
+	if (q->tx_borrowed == cl)
+		q->tx_borrowed = q->tx_class;
+	if (q->tx_class == cl) {
+		q->tx_class = NULL;
+		q->tx_borrowed = NULL;
+	}
+#ifdef CONFIG_NET_CLS_ACT
+	if (q->rx_class == cl)
+		q->rx_class = NULL;
+#endif
+
+	cbq_unlink_class(cl);
+	cbq_adjust_levels(cl->tparent);
+	cl->defmap = 0;
+	cbq_sync_defmap(cl);
+
+	cbq_rmprio(q, cl);
+	sch_tree_unlock(sch);
+
+	cbq_destroy_class(sch, cl);
+	return 0;
+}
+
+static struct tcf_block *cbq_tcf_block(struct Qdisc *sch, unsigned long arg,
+				       struct netlink_ext_ack *extack)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl = (struct cbq_class *)arg;
+
+	if (cl == NULL)
+		cl = &q->link;
+
+	return cl->block;
+}
+
+static unsigned long cbq_bind_filter(struct Qdisc *sch, unsigned long parent,
+				     u32 classid)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *p = (struct cbq_class *)parent;
+	struct cbq_class *cl = cbq_class_lookup(q, classid);
+
+	if (cl) {
+		if (p && p->level <= cl->level)
+			return 0;
+		cl->filters++;
+		return (unsigned long)cl;
+	}
+	return 0;
+}
+
+static void cbq_unbind_filter(struct Qdisc *sch, unsigned long arg)
+{
+	struct cbq_class *cl = (struct cbq_class *)arg;
+
+	cl->filters--;
+}
+
+static void cbq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+	struct cbq_sched_data *q = qdisc_priv(sch);
+	struct cbq_class *cl;
+	unsigned int h;
+
+	if (arg->stop)
+		return;
+
+	for (h = 0; h < q->clhash.hashsize; h++) {
+		hlist_for_each_entry(cl, &q->clhash.hash[h], 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 const struct Qdisc_class_ops cbq_class_ops = {
+	.graft		=	cbq_graft,
+	.leaf		=	cbq_leaf,
+	.qlen_notify	=	cbq_qlen_notify,
+	.find		=	cbq_find,
+	.change		=	cbq_change_class,
+	.delete		=	cbq_delete,
+	.walk		=	cbq_walk,
+	.tcf_block	=	cbq_tcf_block,
+	.bind_tcf	=	cbq_bind_filter,
+	.unbind_tcf	=	cbq_unbind_filter,
+	.dump		=	cbq_dump_class,
+	.dump_stats	=	cbq_dump_class_stats,
+};
+
+static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
+	.next		=	NULL,
+	.cl_ops		=	&cbq_class_ops,
+	.id		=	"cbq",
+	.priv_size	=	sizeof(struct cbq_sched_data),
+	.enqueue	=	cbq_enqueue,
+	.dequeue	=	cbq_dequeue,
+	.peek		=	qdisc_peek_dequeued,
+	.init		=	cbq_init,
+	.reset		=	cbq_reset,
+	.destroy	=	cbq_destroy,
+	.change		=	NULL,
+	.dump		=	cbq_dump,
+	.dump_stats	=	cbq_dump_stats,
+	.owner		=	THIS_MODULE,
+};
+
+static int __init cbq_module_init(void)
+{
+	return register_qdisc(&cbq_qdisc_ops);
+}
+static void __exit cbq_module_exit(void)
+{
+	unregister_qdisc(&cbq_qdisc_ops);
+}
+module_init(cbq_module_init)
+module_exit(cbq_module_exit)
+MODULE_LICENSE("GPL");