/*
   * Copyright (c) 2003 Patrick McHardy, <kaber@trash.net>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version 2
   * of the License, or (at your option) any later version.
   *
   * 2003-10-17 - Ported from altq
   */
  /*
   * Copyright (c) 1997-1999 Carnegie Mellon University. All Rights Reserved.
   *
   * Permission to use, copy, modify, and distribute this software and
   * its documentation is hereby granted (including for commercial or
   * for-profit use), provided that both the copyright notice and this
   * permission notice appear in all copies of the software, derivative
   * works, or modified versions, and any portions thereof.
   *
   * THIS SOFTWARE IS EXPERIMENTAL AND IS KNOWN TO HAVE BUGS, SOME OF
   * WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON PROVIDES THIS
   * SOFTWARE IN ITS ``AS IS'' CONDITION, AND ANY EXPRESS OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
   * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
   * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
   * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *
   * Carnegie Mellon encourages (but does not require) users of this
   * software to return any improvements or extensions that they make,
   * and to grant Carnegie Mellon the rights to redistribute these
   * changes without encumbrance.
   */
  /*
   * H-FSC is described in Proceedings of SIGCOMM'97,
   * "A Hierarchical Fair Service Curve Algorithm for Link-Sharing,
   * Real-Time and Priority Service"
   * by Ion Stoica, Hui Zhang, and T. S. Eugene Ng.
   *
   * Oleg Cherevko <olwi@aq.ml.com.ua> added the upperlimit for link-sharing.
   * when a class has an upperlimit, the fit-time is computed from the
   * upperlimit service curve.  the link-sharing scheduler does not schedule
   * a class whose fit-time exceeds the current time.
   */
  
  #include <linux/kernel.h>

  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/errno.h>

  #include <linux/compiler.h>
  #include <linux/spinlock.h>
  #include <linux/skbuff.h>
  #include <linux/string.h>
  #include <linux/slab.h>

  #include <linux/list.h>
  #include <linux/rbtree.h>
  #include <linux/init.h>

  #include <linux/rtnetlink.h>
  #include <linux/pkt_sched.h>

  #include <net/netlink.h>

  #include <net/pkt_sched.h>
  #include <net/pkt_cls.h>

  #include <asm/div64.h>

  /*
   * kernel internal service curve representation:
   *   coordinates are given by 64 bit unsigned integers.
   *   x-axis: unit is clock count.
   *   y-axis: unit is byte.
   *
   *   The service curve parameters are converted to the internal
   *   representation. The slope values are scaled to avoid overflow.
   *   the inverse slope values as well as the y-projection of the 1st

   *   segment are kept in order to avoid 64-bit divide operations

   *   that are expensive on 32-bit architectures.
   */

  struct internal_sc {

  	u64	sm1;	/* scaled slope of the 1st segment */
  	u64	ism1;	/* scaled inverse-slope of the 1st segment */
  	u64	dx;	/* the x-projection of the 1st segment */
  	u64	dy;	/* the y-projection of the 1st segment */
  	u64	sm2;	/* scaled slope of the 2nd segment */
  	u64	ism2;	/* scaled inverse-slope of the 2nd segment */
  };
  
  /* runtime service curve */

  struct runtime_sc {

  	u64	x;	/* current starting position on x-axis */
  	u64	y;	/* current starting position on y-axis */
  	u64	sm1;	/* scaled slope of the 1st segment */
  	u64	ism1;	/* scaled inverse-slope of the 1st segment */
  	u64	dx;	/* the x-projection of the 1st segment */
  	u64	dy;	/* the y-projection of the 1st segment */
  	u64	sm2;	/* scaled slope of the 2nd segment */
  	u64	ism2;	/* scaled inverse-slope of the 2nd segment */
  };

  enum hfsc_class_flags {

  	HFSC_RSC = 0x1,
  	HFSC_FSC = 0x2,
  	HFSC_USC = 0x4
  };

  struct hfsc_class {

  	struct Qdisc_class_common cl_common;

  	unsigned int	refcnt;		/* usage count */

  	struct gnet_stats_basic_packed bstats;

  	struct gnet_stats_queue qstats;
  	struct gnet_stats_rate_est rate_est;

  	unsigned int	level;		/* class level in hierarchy */
  	struct tcf_proto *filter_list;	/* filter list */
  	unsigned int	filter_cnt;	/* filter count */
  
  	struct hfsc_sched *sched;	/* scheduler data */
  	struct hfsc_class *cl_parent;	/* parent class */
  	struct list_head siblings;	/* sibling classes */
  	struct list_head children;	/* child classes */
  	struct Qdisc	*qdisc;		/* leaf qdisc */
  
  	struct rb_node el_node;		/* qdisc's eligible tree member */
  	struct rb_root vt_tree;		/* active children sorted by cl_vt */
  	struct rb_node vt_node;		/* parent's vt_tree member */
  	struct rb_root cf_tree;		/* active children sorted by cl_f */
  	struct rb_node cf_node;		/* parent's cf_heap member */

  	struct list_head dlist;		/* drop list member */
  
  	u64	cl_total;		/* total work in bytes */
  	u64	cl_cumul;		/* cumulative work in bytes done by
  					   real-time criteria */

  	u64	cl_d;			/* deadline*/
  	u64	cl_e;			/* eligible time */

  	u64	cl_vt;			/* virtual time */
  	u64	cl_f;			/* time when this class will fit for
  					   link-sharing, max(myf, cfmin) */
  	u64	cl_myf;			/* my fit-time (calculated from this
  					   class's own upperlimit curve) */
  	u64	cl_myfadj;		/* my fit-time adjustment (to cancel
  					   history dependence) */
  	u64	cl_cfmin;		/* earliest children's fit-time (used
  					   with cl_myf to obtain cl_f) */
  	u64	cl_cvtmin;		/* minimal virtual time among the
  					   children fit for link-sharing
  					   (monotonic within a period) */
  	u64	cl_vtadj;		/* intra-period cumulative vt
  					   adjustment */
  	u64	cl_vtoff;		/* inter-period cumulative vt offset */
  	u64	cl_cvtmax;		/* max child's vt in the last period */
  	u64	cl_cvtoff;		/* cumulative cvtmax of all periods */

  	u64	cl_pcvtoff;		/* parent's cvtoff at initialization

  					   time */
  
  	struct internal_sc cl_rsc;	/* internal real-time service curve */
  	struct internal_sc cl_fsc;	/* internal fair service curve */
  	struct internal_sc cl_usc;	/* internal upperlimit service curve */
  	struct runtime_sc cl_deadline;	/* deadline curve */
  	struct runtime_sc cl_eligible;	/* eligible curve */
  	struct runtime_sc cl_virtual;	/* virtual curve */
  	struct runtime_sc cl_ulimit;	/* upperlimit curve */
  
  	unsigned long	cl_flags;	/* which curves are valid */
  	unsigned long	cl_vtperiod;	/* vt period sequence number */
  	unsigned long	cl_parentperiod;/* parent's vt period sequence number*/
  	unsigned long	cl_nactive;	/* number of active children */
  };

  struct hfsc_sched {

  	u16	defcls;				/* default class id */
  	struct hfsc_class root;			/* root class */

  	struct Qdisc_class_hash clhash;		/* class hash */

  	struct rb_root eligible;		/* eligible tree */
  	struct list_head droplist;		/* active leaf class list (for
  						   dropping) */

  	struct qdisc_watchdog watchdog;		/* watchdog timer */

  };

  #define	HT_INFINITY	0xffffffffffffffffULL	/* infinite time value */
  
  
  /*
   * eligible tree holds backlogged classes being sorted by their eligible times.
   * there is one eligible tree per hfsc instance.
   */
  
  static void
  eltree_insert(struct hfsc_class *cl)
  {
  	struct rb_node **p = &cl->sched->eligible.rb_node;
  	struct rb_node *parent = NULL;
  	struct hfsc_class *cl1;
  
  	while (*p != NULL) {
  		parent = *p;
  		cl1 = rb_entry(parent, struct hfsc_class, el_node);
  		if (cl->cl_e >= cl1->cl_e)
  			p = &parent->rb_right;
  		else
  			p = &parent->rb_left;
  	}
  	rb_link_node(&cl->el_node, parent, p);
  	rb_insert_color(&cl->el_node, &cl->sched->eligible);
  }
  
  static inline void
  eltree_remove(struct hfsc_class *cl)
  {
  	rb_erase(&cl->el_node, &cl->sched->eligible);
  }
  
  static inline void
  eltree_update(struct hfsc_class *cl)
  {
  	eltree_remove(cl);
  	eltree_insert(cl);
  }
  
  /* find the class with the minimum deadline among the eligible classes */
  static inline struct hfsc_class *
  eltree_get_mindl(struct hfsc_sched *q, u64 cur_time)
  {
  	struct hfsc_class *p, *cl = NULL;
  	struct rb_node *n;
  
  	for (n = rb_first(&q->eligible); n != NULL; n = rb_next(n)) {
  		p = rb_entry(n, struct hfsc_class, el_node);
  		if (p->cl_e > cur_time)
  			break;
  		if (cl == NULL || p->cl_d < cl->cl_d)
  			cl = p;
  	}
  	return cl;
  }
  
  /* find the class with minimum eligible time among the eligible classes */
  static inline struct hfsc_class *
  eltree_get_minel(struct hfsc_sched *q)
  {
  	struct rb_node *n;

  	n = rb_first(&q->eligible);
  	if (n == NULL)
  		return NULL;
  	return rb_entry(n, struct hfsc_class, el_node);
  }
  
  /*
   * vttree holds holds backlogged child classes being sorted by their virtual
   * time. each intermediate class has one vttree.
   */
  static void
  vttree_insert(struct hfsc_class *cl)
  {
  	struct rb_node **p = &cl->cl_parent->vt_tree.rb_node;
  	struct rb_node *parent = NULL;
  	struct hfsc_class *cl1;
  
  	while (*p != NULL) {
  		parent = *p;
  		cl1 = rb_entry(parent, struct hfsc_class, vt_node);
  		if (cl->cl_vt >= cl1->cl_vt)
  			p = &parent->rb_right;
  		else
  			p = &parent->rb_left;
  	}
  	rb_link_node(&cl->vt_node, parent, p);
  	rb_insert_color(&cl->vt_node, &cl->cl_parent->vt_tree);
  }
  
  static inline void
  vttree_remove(struct hfsc_class *cl)
  {
  	rb_erase(&cl->vt_node, &cl->cl_parent->vt_tree);
  }
  
  static inline void
  vttree_update(struct hfsc_class *cl)
  {
  	vttree_remove(cl);
  	vttree_insert(cl);
  }
  
  static inline struct hfsc_class *
  vttree_firstfit(struct hfsc_class *cl, u64 cur_time)
  {
  	struct hfsc_class *p;
  	struct rb_node *n;
  
  	for (n = rb_first(&cl->vt_tree); n != NULL; n = rb_next(n)) {
  		p = rb_entry(n, struct hfsc_class, vt_node);
  		if (p->cl_f <= cur_time)
  			return p;
  	}
  	return NULL;
  }
  
  /*
   * get the leaf class with the minimum vt in the hierarchy
   */
  static struct hfsc_class *
  vttree_get_minvt(struct hfsc_class *cl, u64 cur_time)
  {
  	/* if root-class's cfmin is bigger than cur_time nothing to do */
  	if (cl->cl_cfmin > cur_time)
  		return NULL;
  
  	while (cl->level > 0) {
  		cl = vttree_firstfit(cl, cur_time);
  		if (cl == NULL)
  			return NULL;
  		/*
  		 * update parent's cl_cvtmin.
  		 */
  		if (cl->cl_parent->cl_cvtmin < cl->cl_vt)
  			cl->cl_parent->cl_cvtmin = cl->cl_vt;
  	}
  	return cl;
  }
  
  static void
  cftree_insert(struct hfsc_class *cl)
  {
  	struct rb_node **p = &cl->cl_parent->cf_tree.rb_node;
  	struct rb_node *parent = NULL;
  	struct hfsc_class *cl1;
  
  	while (*p != NULL) {
  		parent = *p;
  		cl1 = rb_entry(parent, struct hfsc_class, cf_node);
  		if (cl->cl_f >= cl1->cl_f)
  			p = &parent->rb_right;
  		else
  			p = &parent->rb_left;
  	}
  	rb_link_node(&cl->cf_node, parent, p);
  	rb_insert_color(&cl->cf_node, &cl->cl_parent->cf_tree);
  }
  
  static inline void
  cftree_remove(struct hfsc_class *cl)
  {
  	rb_erase(&cl->cf_node, &cl->cl_parent->cf_tree);
  }
  
  static inline void
  cftree_update(struct hfsc_class *cl)
  {
  	cftree_remove(cl);
  	cftree_insert(cl);
  }
  
  /*
   * service curve support functions
   *
   *  external service curve parameters
   *	m: bps
   *	d: us
   *  internal service curve parameters
   *	sm: (bytes/psched_us) << SM_SHIFT
   *	ism: (psched_us/byte) << ISM_SHIFT
   *	dx: psched_us
   *

   * The clock source resolution with ktime and PSCHED_SHIFT 10 is 1.024us.

   *
   * sm and ism are scaled in order to keep effective digits.
   * SM_SHIFT and ISM_SHIFT are selected to keep at least 4 effective
   * digits in decimal using the following table.
   *

   *  bits/sec      100Kbps     1Mbps     10Mbps     100Mbps    1Gbps
   *  ------------+-------------------------------------------------------

   *  bytes/1.024us 12.8e-3    128e-3     1280e-3    12800e-3   128000e-3

   *

   *  1.024us/byte  78.125     7.8125     0.78125    0.078125   0.0078125

   *
   * So, for PSCHED_SHIFT 10 we need: SM_SHIFT 20, ISM_SHIFT 18.

   */

  #define	SM_SHIFT	(30 - PSCHED_SHIFT)
  #define	ISM_SHIFT	(8 + PSCHED_SHIFT)

  
  #define	SM_MASK		((1ULL << SM_SHIFT) - 1)
  #define	ISM_MASK	((1ULL << ISM_SHIFT) - 1)
  
  static inline u64
  seg_x2y(u64 x, u64 sm)
  {
  	u64 y;
  
  	/*
  	 * compute
  	 *	y = x * sm >> SM_SHIFT
  	 * but divide it for the upper and lower bits to avoid overflow
  	 */
  	y = (x >> SM_SHIFT) * sm + (((x & SM_MASK) * sm) >> SM_SHIFT);
  	return y;
  }
  
  static inline u64
  seg_y2x(u64 y, u64 ism)
  {
  	u64 x;
  
  	if (y == 0)
  		x = 0;
  	else if (ism == HT_INFINITY)
  		x = HT_INFINITY;
  	else {
  		x = (y >> ISM_SHIFT) * ism
  		    + (((y & ISM_MASK) * ism) >> ISM_SHIFT);
  	}
  	return x;
  }
  
  /* Convert m (bps) into sm (bytes/psched us) */
  static u64
  m2sm(u32 m)
  {
  	u64 sm;
  
  	sm = ((u64)m << SM_SHIFT);

  	sm += PSCHED_TICKS_PER_SEC - 1;
  	do_div(sm, PSCHED_TICKS_PER_SEC);

  	return sm;
  }
  
  /* convert m (bps) into ism (psched us/byte) */
  static u64
  m2ism(u32 m)
  {
  	u64 ism;
  
  	if (m == 0)
  		ism = HT_INFINITY;
  	else {

  		ism = ((u64)PSCHED_TICKS_PER_SEC << ISM_SHIFT);

  		ism += m - 1;
  		do_div(ism, m);
  	}
  	return ism;
  }
  
  /* convert d (us) into dx (psched us) */
  static u64
  d2dx(u32 d)
  {
  	u64 dx;

  	dx = ((u64)d * PSCHED_TICKS_PER_SEC);

  	dx += USEC_PER_SEC - 1;
  	do_div(dx, USEC_PER_SEC);

  	return dx;
  }
  
  /* convert sm (bytes/psched us) into m (bps) */
  static u32
  sm2m(u64 sm)
  {
  	u64 m;

  	m = (sm * PSCHED_TICKS_PER_SEC) >> SM_SHIFT;

  	return (u32)m;
  }
  
  /* convert dx (psched us) into d (us) */
  static u32
  dx2d(u64 dx)
  {
  	u64 d;

  	d = dx * USEC_PER_SEC;

  	do_div(d, PSCHED_TICKS_PER_SEC);

  	return (u32)d;
  }
  
  static void
  sc2isc(struct tc_service_curve *sc, struct internal_sc *isc)
  {
  	isc->sm1  = m2sm(sc->m1);
  	isc->ism1 = m2ism(sc->m1);
  	isc->dx   = d2dx(sc->d);
  	isc->dy   = seg_x2y(isc->dx, isc->sm1);
  	isc->sm2  = m2sm(sc->m2);
  	isc->ism2 = m2ism(sc->m2);
  }
  
  /*
   * initialize the runtime service curve with the given internal
   * service curve starting at (x, y).
   */
  static void
  rtsc_init(struct runtime_sc *rtsc, struct internal_sc *isc, u64 x, u64 y)
  {
  	rtsc->x	   = x;
  	rtsc->y    = y;
  	rtsc->sm1  = isc->sm1;
  	rtsc->ism1 = isc->ism1;
  	rtsc->dx   = isc->dx;
  	rtsc->dy   = isc->dy;
  	rtsc->sm2  = isc->sm2;
  	rtsc->ism2 = isc->ism2;
  }
  
  /*
   * calculate the y-projection of the runtime service curve by the
   * given x-projection value
   */
  static u64
  rtsc_y2x(struct runtime_sc *rtsc, u64 y)
  {
  	u64 x;
  
  	if (y < rtsc->y)
  		x = rtsc->x;
  	else if (y <= rtsc->y + rtsc->dy) {
  		/* x belongs to the 1st segment */
  		if (rtsc->dy == 0)
  			x = rtsc->x + rtsc->dx;
  		else
  			x = rtsc->x + seg_y2x(y - rtsc->y, rtsc->ism1);
  	} else {
  		/* x belongs to the 2nd segment */
  		x = rtsc->x + rtsc->dx
  		    + seg_y2x(y - rtsc->y - rtsc->dy, rtsc->ism2);
  	}
  	return x;
  }
  
  static u64
  rtsc_x2y(struct runtime_sc *rtsc, u64 x)
  {
  	u64 y;
  
  	if (x <= rtsc->x)
  		y = rtsc->y;
  	else if (x <= rtsc->x + rtsc->dx)
  		/* y belongs to the 1st segment */
  		y = rtsc->y + seg_x2y(x - rtsc->x, rtsc->sm1);
  	else
  		/* y belongs to the 2nd segment */
  		y = rtsc->y + rtsc->dy
  		    + seg_x2y(x - rtsc->x - rtsc->dx, rtsc->sm2);
  	return y;
  }
  
  /*
   * update the runtime service curve by taking the minimum of the current
   * runtime service curve and the service curve starting at (x, y).
   */
  static void
  rtsc_min(struct runtime_sc *rtsc, struct internal_sc *isc, u64 x, u64 y)
  {
  	u64 y1, y2, dx, dy;
  	u32 dsm;
  
  	if (isc->sm1 <= isc->sm2) {
  		/* service curve is convex */
  		y1 = rtsc_x2y(rtsc, x);
  		if (y1 < y)
  			/* the current rtsc is smaller */
  			return;
  		rtsc->x = x;
  		rtsc->y = y;
  		return;
  	}
  
  	/*
  	 * service curve is concave
  	 * compute the two y values of the current rtsc
  	 *	y1: at x
  	 *	y2: at (x + dx)
  	 */
  	y1 = rtsc_x2y(rtsc, x);
  	if (y1 <= y) {
  		/* rtsc is below isc, no change to rtsc */
  		return;
  	}
  
  	y2 = rtsc_x2y(rtsc, x + isc->dx);
  	if (y2 >= y + isc->dy) {
  		/* rtsc is above isc, replace rtsc by isc */
  		rtsc->x = x;
  		rtsc->y = y;
  		rtsc->dx = isc->dx;
  		rtsc->dy = isc->dy;
  		return;
  	}
  
  	/*
  	 * the two curves intersect
  	 * compute the offsets (dx, dy) using the reverse
  	 * function of seg_x2y()
  	 *	seg_x2y(dx, sm1) == seg_x2y(dx, sm2) + (y1 - y)
  	 */
  	dx = (y1 - y) << SM_SHIFT;
  	dsm = isc->sm1 - isc->sm2;
  	do_div(dx, dsm);
  	/*
  	 * check if (x, y1) belongs to the 1st segment of rtsc.
  	 * if so, add the offset.
  	 */
  	if (rtsc->x + rtsc->dx > x)
  		dx += rtsc->x + rtsc->dx - x;
  	dy = seg_x2y(dx, isc->sm1);
  
  	rtsc->x = x;
  	rtsc->y = y;
  	rtsc->dx = dx;
  	rtsc->dy = dy;

  }
  
  static void
  init_ed(struct hfsc_class *cl, unsigned int next_len)
  {

  	u64 cur_time = psched_get_time();

  
  	/* update the deadline curve */
  	rtsc_min(&cl->cl_deadline, &cl->cl_rsc, cur_time, cl->cl_cumul);
  
  	/*
  	 * update the eligible curve.
  	 * for concave, it is equal to the deadline curve.
  	 * for convex, it is a linear curve with slope m2.
  	 */
  	cl->cl_eligible = cl->cl_deadline;
  	if (cl->cl_rsc.sm1 <= cl->cl_rsc.sm2) {
  		cl->cl_eligible.dx = 0;
  		cl->cl_eligible.dy = 0;
  	}
  
  	/* compute e and d */
  	cl->cl_e = rtsc_y2x(&cl->cl_eligible, cl->cl_cumul);
  	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
  
  	eltree_insert(cl);
  }
  
  static void
  update_ed(struct hfsc_class *cl, unsigned int next_len)
  {
  	cl->cl_e = rtsc_y2x(&cl->cl_eligible, cl->cl_cumul);
  	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
  
  	eltree_update(cl);
  }
  
  static inline void
  update_d(struct hfsc_class *cl, unsigned int next_len)
  {
  	cl->cl_d = rtsc_y2x(&cl->cl_deadline, cl->cl_cumul + next_len);
  }
  
  static inline void
  update_cfmin(struct hfsc_class *cl)
  {
  	struct rb_node *n = rb_first(&cl->cf_tree);
  	struct hfsc_class *p;
  
  	if (n == NULL) {
  		cl->cl_cfmin = 0;
  		return;
  	}
  	p = rb_entry(n, struct hfsc_class, cf_node);
  	cl->cl_cfmin = p->cl_f;
  }
  
  static void
  init_vf(struct hfsc_class *cl, unsigned int len)
  {
  	struct hfsc_class *max_cl;
  	struct rb_node *n;
  	u64 vt, f, cur_time;
  	int go_active;
  
  	cur_time = 0;
  	go_active = 1;
  	for (; cl->cl_parent != NULL; cl = cl->cl_parent) {
  		if (go_active && cl->cl_nactive++ == 0)
  			go_active = 1;
  		else
  			go_active = 0;
  
  		if (go_active) {
  			n = rb_last(&cl->cl_parent->vt_tree);
  			if (n != NULL) {

  				max_cl = rb_entry(n, struct hfsc_class, vt_node);

  				/*
  				 * set vt to the average of the min and max
  				 * classes.  if the parent's period didn't
  				 * change, don't decrease vt of the class.
  				 */
  				vt = max_cl->cl_vt;
  				if (cl->cl_parent->cl_cvtmin != 0)
  					vt = (cl->cl_parent->cl_cvtmin + vt)/2;
  
  				if (cl->cl_parent->cl_vtperiod !=
  				    cl->cl_parentperiod || vt > cl->cl_vt)
  					cl->cl_vt = vt;
  			} else {
  				/*
  				 * first child for a new parent backlog period.
  				 * add parent's cvtmax to cvtoff to make a new
  				 * vt (vtoff + vt) larger than the vt in the
  				 * last period for all children.
  				 */
  				vt = cl->cl_parent->cl_cvtmax;
  				cl->cl_parent->cl_cvtoff += vt;
  				cl->cl_parent->cl_cvtmax = 0;
  				cl->cl_parent->cl_cvtmin = 0;
  				cl->cl_vt = 0;
  			}
  
  			cl->cl_vtoff = cl->cl_parent->cl_cvtoff -
  							cl->cl_pcvtoff;
  
  			/* update the virtual curve */
  			vt = cl->cl_vt + cl->cl_vtoff;
  			rtsc_min(&cl->cl_virtual, &cl->cl_fsc, vt,

  						      cl->cl_total);

  			if (cl->cl_virtual.x == vt) {
  				cl->cl_virtual.x -= cl->cl_vtoff;
  				cl->cl_vtoff = 0;
  			}
  			cl->cl_vtadj = 0;
  
  			cl->cl_vtperiod++;  /* increment vt period */
  			cl->cl_parentperiod = cl->cl_parent->cl_vtperiod;
  			if (cl->cl_parent->cl_nactive == 0)
  				cl->cl_parentperiod++;
  			cl->cl_f = 0;
  
  			vttree_insert(cl);
  			cftree_insert(cl);
  
  			if (cl->cl_flags & HFSC_USC) {
  				/* class has upper limit curve */
  				if (cur_time == 0)

  					cur_time = psched_get_time();

  
  				/* update the ulimit curve */
  				rtsc_min(&cl->cl_ulimit, &cl->cl_usc, cur_time,

  					 cl->cl_total);

  				/* compute myf */
  				cl->cl_myf = rtsc_y2x(&cl->cl_ulimit,

  						      cl->cl_total);

  				cl->cl_myfadj = 0;
  			}
  		}
  
  		f = max(cl->cl_myf, cl->cl_cfmin);
  		if (f != cl->cl_f) {
  			cl->cl_f = f;
  			cftree_update(cl);

  		}

  		update_cfmin(cl->cl_parent);

  	}
  }
  
  static void
  update_vf(struct hfsc_class *cl, unsigned int len, u64 cur_time)
  {
  	u64 f; /* , myf_bound, delta; */
  	int go_passive = 0;
  
  	if (cl->qdisc->q.qlen == 0 && cl->cl_flags & HFSC_FSC)
  		go_passive = 1;
  
  	for (; cl->cl_parent != NULL; cl = cl->cl_parent) {
  		cl->cl_total += len;
  
  		if (!(cl->cl_flags & HFSC_FSC) || cl->cl_nactive == 0)
  			continue;
  
  		if (go_passive && --cl->cl_nactive == 0)
  			go_passive = 1;
  		else
  			go_passive = 0;
  
  		if (go_passive) {
  			/* no more active child, going passive */
  
  			/* update cvtmax of the parent class */
  			if (cl->cl_vt > cl->cl_parent->cl_cvtmax)
  				cl->cl_parent->cl_cvtmax = cl->cl_vt;
  
  			/* remove this class from the vt tree */
  			vttree_remove(cl);
  
  			cftree_remove(cl);
  			update_cfmin(cl->cl_parent);
  
  			continue;
  		}
  
  		/*
  		 * update vt and f
  		 */
  		cl->cl_vt = rtsc_y2x(&cl->cl_virtual, cl->cl_total)

  			    - cl->cl_vtoff + cl->cl_vtadj;

  
  		/*
  		 * if vt of the class is smaller than cvtmin,
  		 * the class was skipped in the past due to non-fit.
  		 * if so, we need to adjust vtadj.
  		 */
  		if (cl->cl_vt < cl->cl_parent->cl_cvtmin) {
  			cl->cl_vtadj += cl->cl_parent->cl_cvtmin - cl->cl_vt;
  			cl->cl_vt = cl->cl_parent->cl_cvtmin;
  		}
  
  		/* update the vt tree */
  		vttree_update(cl);
  
  		if (cl->cl_flags & HFSC_USC) {
  			cl->cl_myf = cl->cl_myfadj + rtsc_y2x(&cl->cl_ulimit,

  							      cl->cl_total);

  #if 0
  			/*
  			 * This code causes classes to stay way under their
  			 * limit when multiple classes are used at gigabit
  			 * speed. needs investigation. -kaber
  			 */
  			/*
  			 * if myf lags behind by more than one clock tick
  			 * from the current time, adjust myfadj to prevent
  			 * a rate-limited class from going greedy.
  			 * in a steady state under rate-limiting, myf
  			 * fluctuates within one clock tick.
  			 */
  			myf_bound = cur_time - PSCHED_JIFFIE2US(1);
  			if (cl->cl_myf < myf_bound) {
  				delta = cur_time - cl->cl_myf;
  				cl->cl_myfadj += delta;
  				cl->cl_myf += delta;
  			}
  #endif
  		}
  
  		f = max(cl->cl_myf, cl->cl_cfmin);
  		if (f != cl->cl_f) {
  			cl->cl_f = f;
  			cftree_update(cl);
  			update_cfmin(cl->cl_parent);
  		}
  	}
  }
  
  static void
  set_active(struct hfsc_class *cl, unsigned int len)
  {
  	if (cl->cl_flags & HFSC_RSC)
  		init_ed(cl, len);
  	if (cl->cl_flags & HFSC_FSC)
  		init_vf(cl, len);
  
  	list_add_tail(&cl->dlist, &cl->sched->droplist);
  }
  
  static void
  set_passive(struct hfsc_class *cl)
  {
  	if (cl->cl_flags & HFSC_RSC)
  		eltree_remove(cl);
  
  	list_del(&cl->dlist);
  
  	/*
  	 * vttree is now handled in update_vf() so that update_vf(cl, 0, 0)
  	 * needs to be called explicitly to remove a class from vttree.
  	 */
  }

  static unsigned int
  qdisc_peek_len(struct Qdisc *sch)
  {
  	struct sk_buff *skb;
  	unsigned int len;

  	skb = sch->ops->peek(sch);

  	if (skb == NULL) {

  		qdisc_warn_nonwc("qdisc_peek_len", sch);

  		return 0;
  	}

  	len = qdisc_pkt_len(skb);

  	return len;
  }
  
  static void
  hfsc_purge_queue(struct Qdisc *sch, struct hfsc_class *cl)
  {
  	unsigned int len = cl->qdisc->q.qlen;
  
  	qdisc_reset(cl->qdisc);

  	qdisc_tree_decrease_qlen(cl->qdisc, len);

  }
  
  static void
  hfsc_adjust_levels(struct hfsc_class *cl)
  {
  	struct hfsc_class *p;
  	unsigned int level;
  
  	do {
  		level = 0;
  		list_for_each_entry(p, &cl->children, siblings) {

  			if (p->level >= level)
  				level = p->level + 1;

  		}

  		cl->level = level;

  	} while ((cl = cl->cl_parent) != NULL);
  }

  static inline struct hfsc_class *
  hfsc_find_class(u32 classid, struct Qdisc *sch)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);

  	struct Qdisc_class_common *clc;

  	clc = qdisc_class_find(&q->clhash, classid);
  	if (clc == NULL)
  		return NULL;
  	return container_of(clc, struct hfsc_class, cl_common);

  }
  
  static void
  hfsc_change_rsc(struct hfsc_class *cl, struct tc_service_curve *rsc,

  		u64 cur_time)

  {
  	sc2isc(rsc, &cl->cl_rsc);
  	rtsc_init(&cl->cl_deadline, &cl->cl_rsc, cur_time, cl->cl_cumul);
  	cl->cl_eligible = cl->cl_deadline;
  	if (cl->cl_rsc.sm1 <= cl->cl_rsc.sm2) {
  		cl->cl_eligible.dx = 0;
  		cl->cl_eligible.dy = 0;
  	}
  	cl->cl_flags |= HFSC_RSC;
  }
  
  static void
  hfsc_change_fsc(struct hfsc_class *cl, struct tc_service_curve *fsc)
  {
  	sc2isc(fsc, &cl->cl_fsc);
  	rtsc_init(&cl->cl_virtual, &cl->cl_fsc, cl->cl_vt, cl->cl_total);
  	cl->cl_flags |= HFSC_FSC;
  }
  
  static void
  hfsc_change_usc(struct hfsc_class *cl, struct tc_service_curve *usc,

  		u64 cur_time)

  {
  	sc2isc(usc, &cl->cl_usc);
  	rtsc_init(&cl->cl_ulimit, &cl->cl_usc, cur_time, cl->cl_total);
  	cl->cl_flags |= HFSC_USC;
  }

  static const struct nla_policy hfsc_policy[TCA_HFSC_MAX + 1] = {
  	[TCA_HFSC_RSC]	= { .len = sizeof(struct tc_service_curve) },
  	[TCA_HFSC_FSC]	= { .len = sizeof(struct tc_service_curve) },
  	[TCA_HFSC_USC]	= { .len = sizeof(struct tc_service_curve) },
  };

  static int
  hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,

  		  struct nlattr **tca, unsigned long *arg)

  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl = (struct hfsc_class *)*arg;
  	struct hfsc_class *parent = NULL;

  	struct nlattr *opt = tca[TCA_OPTIONS];
  	struct nlattr *tb[TCA_HFSC_MAX + 1];

  	struct tc_service_curve *rsc = NULL, *fsc = NULL, *usc = NULL;
  	u64 cur_time;

  	int err;

  	if (opt == NULL)

  		return -EINVAL;

  	err = nla_parse_nested(tb, TCA_HFSC_MAX, opt, hfsc_policy);

  	if (err < 0)
  		return err;

  	if (tb[TCA_HFSC_RSC]) {

  		rsc = nla_data(tb[TCA_HFSC_RSC]);

  		if (rsc->m1 == 0 && rsc->m2 == 0)
  			rsc = NULL;
  	}

  	if (tb[TCA_HFSC_FSC]) {

  		fsc = nla_data(tb[TCA_HFSC_FSC]);

  		if (fsc->m1 == 0 && fsc->m2 == 0)
  			fsc = NULL;
  	}

  	if (tb[TCA_HFSC_USC]) {

  		usc = nla_data(tb[TCA_HFSC_USC]);

  		if (usc->m1 == 0 && usc->m2 == 0)
  			usc = NULL;
  	}
  
  	if (cl != NULL) {
  		if (parentid) {

  			if (cl->cl_parent &&
  			    cl->cl_parent->cl_common.classid != parentid)

  				return -EINVAL;
  			if (cl->cl_parent == NULL && parentid != TC_H_ROOT)
  				return -EINVAL;
  		}

  		cur_time = psched_get_time();

  		if (tca[TCA_RATE]) {
  			err = gen_replace_estimator(&cl->bstats, &cl->rate_est,
  					      qdisc_root_sleeping_lock(sch),
  					      tca[TCA_RATE]);
  			if (err)
  				return err;
  		}

  		sch_tree_lock(sch);
  		if (rsc != NULL)
  			hfsc_change_rsc(cl, rsc, cur_time);
  		if (fsc != NULL)
  			hfsc_change_fsc(cl, fsc);
  		if (usc != NULL)
  			hfsc_change_usc(cl, usc, cur_time);
  
  		if (cl->qdisc->q.qlen != 0) {
  			if (cl->cl_flags & HFSC_RSC)
  				update_ed(cl, qdisc_peek_len(cl->qdisc));
  			if (cl->cl_flags & HFSC_FSC)
  				update_vf(cl, 0, cur_time);
  		}
  		sch_tree_unlock(sch);

  		return 0;
  	}
  
  	if (parentid == TC_H_ROOT)
  		return -EEXIST;
  
  	parent = &q->root;
  	if (parentid) {
  		parent = hfsc_find_class(parentid, sch);
  		if (parent == NULL)
  			return -ENOENT;
  	}
  
  	if (classid == 0 || TC_H_MAJ(classid ^ sch->handle) != 0)
  		return -EINVAL;
  	if (hfsc_find_class(classid, sch))
  		return -EEXIST;
  
  	if (rsc == NULL && fsc == NULL)
  		return -EINVAL;

  	cl = kzalloc(sizeof(struct hfsc_class), GFP_KERNEL);

  	if (cl == NULL)
  		return -ENOBUFS;

  	if (tca[TCA_RATE]) {
  		err = gen_new_estimator(&cl->bstats, &cl->rate_est,
  					qdisc_root_sleeping_lock(sch),
  					tca[TCA_RATE]);
  		if (err) {
  			kfree(cl);
  			return err;
  		}
  	}

  	if (rsc != NULL)
  		hfsc_change_rsc(cl, rsc, 0);
  	if (fsc != NULL)
  		hfsc_change_fsc(cl, fsc);
  	if (usc != NULL)
  		hfsc_change_usc(cl, usc, 0);

  	cl->cl_common.classid = classid;

  	cl->refcnt    = 1;

  	cl->sched     = q;
  	cl->cl_parent = parent;

  	cl->qdisc = qdisc_create_dflt(sch->dev_queue,

  				      &pfifo_qdisc_ops, classid);

  	if (cl->qdisc == NULL)
  		cl->qdisc = &noop_qdisc;

  	INIT_LIST_HEAD(&cl->children);
  	cl->vt_tree = RB_ROOT;
  	cl->cf_tree = RB_ROOT;
  
  	sch_tree_lock(sch);

  	qdisc_class_hash_insert(&q->clhash, &cl->cl_common);

  	list_add_tail(&cl->siblings, &parent->children);
  	if (parent->level == 0)
  		hfsc_purge_queue(sch, parent);
  	hfsc_adjust_levels(parent);
  	cl->cl_pcvtoff = parent->cl_cvtoff;
  	sch_tree_unlock(sch);

  	qdisc_class_hash_grow(sch, &q->clhash);

  	*arg = (unsigned long)cl;
  	return 0;
  }
  
  static void

  hfsc_destroy_class(struct Qdisc *sch, struct hfsc_class *cl)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);

  	tcf_destroy_chain(&cl->filter_list);

  	qdisc_destroy(cl->qdisc);

  	gen_kill_estimator(&cl->bstats, &cl->rate_est);

  	if (cl != &q->root)
  		kfree(cl);
  }
  
  static int
  hfsc_delete_class(struct Qdisc *sch, unsigned long arg)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl = (struct hfsc_class *)arg;
  
  	if (cl->level > 0 || cl->filter_cnt > 0 || cl == &q->root)
  		return -EBUSY;
  
  	sch_tree_lock(sch);

  	list_del(&cl->siblings);
  	hfsc_adjust_levels(cl->cl_parent);

  	hfsc_purge_queue(sch, cl);

  	qdisc_class_hash_remove(&q->clhash, &cl->cl_common);

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

  
  	sch_tree_unlock(sch);
  	return 0;
  }
  
  static struct hfsc_class *
  hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);

  	struct hfsc_class *head, *cl;

  	struct tcf_result res;
  	struct tcf_proto *tcf;
  	int result;
  
  	if (TC_H_MAJ(skb->priority ^ sch->handle) == 0 &&
  	    (cl = hfsc_find_class(skb->priority, sch)) != NULL)
  		if (cl->level == 0)
  			return cl;

  	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;

  	head = &q->root;

  	tcf = q->root.filter_list;
  	while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
  #ifdef CONFIG_NET_CLS_ACT
  		switch (result) {
  		case TC_ACT_QUEUED:

  		case TC_ACT_STOLEN:

  			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;

  		case TC_ACT_SHOT:

  			return NULL;
  		}

  #endif

  		cl = (struct hfsc_class *)res.class;
  		if (!cl) {
  			cl = hfsc_find_class(res.classid, sch);
  			if (!cl)

  				break; /* filter selected invalid classid */

  			if (cl->level >= head->level)
  				break; /* filter may only point downwards */

  		}
  
  		if (cl->level == 0)
  			return cl; /* hit leaf class */
  
  		/* apply inner filter chain */
  		tcf = cl->filter_list;

  		head = cl;

  	}
  
  	/* classification failed, try default class */
  	cl = hfsc_find_class(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
  	if (cl == NULL || cl->level > 0)
  		return NULL;
  
  	return cl;
  }
  
  static int
  hfsc_graft_class(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,

  		 struct Qdisc **old)

  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;

  	if (cl->level > 0)
  		return -EINVAL;
  	if (new == NULL) {

  		new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,

  					cl->cl_common.classid);

  		if (new == NULL)
  			new = &noop_qdisc;
  	}
  
  	sch_tree_lock(sch);
  	hfsc_purge_queue(sch, cl);

  	*old = cl->qdisc;
  	cl->qdisc = new;

  	sch_tree_unlock(sch);
  	return 0;
  }
  
  static struct Qdisc *
  hfsc_class_leaf(struct Qdisc *sch, unsigned long arg)
  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;

  	if (cl->level == 0)

  		return cl->qdisc;
  
  	return NULL;
  }

  static void
  hfsc_qlen_notify(struct Qdisc *sch, unsigned long arg)
  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;
  
  	if (cl->qdisc->q.qlen == 0) {
  		update_vf(cl, 0, 0);
  		set_passive(cl);
  	}
  }

  static unsigned long
  hfsc_get_class(struct Qdisc *sch, u32 classid)
  {
  	struct hfsc_class *cl = hfsc_find_class(classid, sch);
  
  	if (cl != NULL)
  		cl->refcnt++;
  
  	return (unsigned long)cl;
  }
  
  static void
  hfsc_put_class(struct Qdisc *sch, unsigned long arg)
  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;
  
  	if (--cl->refcnt == 0)
  		hfsc_destroy_class(sch, cl);
  }
  
  static unsigned long
  hfsc_bind_tcf(struct Qdisc *sch, unsigned long parent, u32 classid)
  {
  	struct hfsc_class *p = (struct hfsc_class *)parent;
  	struct hfsc_class *cl = hfsc_find_class(classid, sch);
  
  	if (cl != NULL) {
  		if (p != NULL && p->level <= cl->level)
  			return 0;
  		cl->filter_cnt++;
  	}
  
  	return (unsigned long)cl;
  }
  
  static void
  hfsc_unbind_tcf(struct Qdisc *sch, unsigned long arg)
  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;
  
  	cl->filter_cnt--;
  }
  
  static struct tcf_proto **
  hfsc_tcf_chain(struct Qdisc *sch, unsigned long arg)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl = (struct hfsc_class *)arg;
  
  	if (cl == NULL)
  		cl = &q->root;
  
  	return &cl->filter_list;
  }
  
  static int
  hfsc_dump_sc(struct sk_buff *skb, int attr, struct internal_sc *sc)
  {
  	struct tc_service_curve tsc;
  
  	tsc.m1 = sm2m(sc->sm1);
  	tsc.d  = dx2d(sc->dx);
  	tsc.m2 = sm2m(sc->sm2);

  	NLA_PUT(skb, attr, sizeof(tsc), &tsc);

  
  	return skb->len;

   nla_put_failure:

  	return -1;
  }

  static int

  hfsc_dump_curves(struct sk_buff *skb, struct hfsc_class *cl)
  {
  	if ((cl->cl_flags & HFSC_RSC) &&
  	    (hfsc_dump_sc(skb, TCA_HFSC_RSC, &cl->cl_rsc) < 0))

  		goto nla_put_failure;

  
  	if ((cl->cl_flags & HFSC_FSC) &&
  	    (hfsc_dump_sc(skb, TCA_HFSC_FSC, &cl->cl_fsc) < 0))

  		goto nla_put_failure;

  
  	if ((cl->cl_flags & HFSC_USC) &&
  	    (hfsc_dump_sc(skb, TCA_HFSC_USC, &cl->cl_usc) < 0))

  		goto nla_put_failure;

  
  	return skb->len;

   nla_put_failure:

  	return -1;
  }
  
  static int
  hfsc_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb,

  		struct tcmsg *tcm)

  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;

  	struct nlattr *nest;

  	tcm->tcm_parent = cl->cl_parent ? cl->cl_parent->cl_common.classid :
  					  TC_H_ROOT;
  	tcm->tcm_handle = cl->cl_common.classid;

  	if (cl->level == 0)
  		tcm->tcm_info = cl->qdisc->handle;

  	nest = nla_nest_start(skb, TCA_OPTIONS);
  	if (nest == NULL)
  		goto nla_put_failure;

  	if (hfsc_dump_curves(skb, cl) < 0)

  		goto nla_put_failure;

  	nla_nest_end(skb, nest);

  	return skb->len;

   nla_put_failure:

  	nla_nest_cancel(skb, nest);

  	return -EMSGSIZE;

  }
  
  static int
  hfsc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
  	struct gnet_dump *d)
  {
  	struct hfsc_class *cl = (struct hfsc_class *)arg;
  	struct tc_hfsc_stats xstats;
  
  	cl->qstats.qlen = cl->qdisc->q.qlen;

  	cl->qstats.backlog = cl->qdisc->qstats.backlog;

  	xstats.level   = cl->level;
  	xstats.period  = cl->cl_vtperiod;
  	xstats.work    = cl->cl_total;
  	xstats.rtwork  = cl->cl_cumul;
  
  	if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||

  	    gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||

  	    gnet_stats_copy_queue(d, &cl->qstats) < 0)
  		return -1;
  
  	return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
  }
  
  
  
  static void
  hfsc_walk(struct Qdisc *sch, struct qdisc_walker *arg)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);

  	struct hlist_node *n;

  	struct hfsc_class *cl;
  	unsigned int i;
  
  	if (arg->stop)
  		return;

  	for (i = 0; i < q->clhash.hashsize; i++) {
  		hlist_for_each_entry(cl, n, &q->clhash.hash[i],
  				     cl_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 void

  hfsc_schedule_watchdog(struct Qdisc *sch)

  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl;
  	u64 next_time = 0;

  	cl = eltree_get_minel(q);
  	if (cl)

  		next_time = cl->cl_e;
  	if (q->root.cl_cfmin != 0) {
  		if (next_time == 0 || next_time > q->root.cl_cfmin)
  			next_time = q->root.cl_cfmin;
  	}

  	WARN_ON(next_time == 0);

  	qdisc_watchdog_schedule(&q->watchdog, next_time);

  }
  
  static int

  hfsc_init_qdisc(struct Qdisc *sch, struct nlattr *opt)

  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct tc_hfsc_qopt *qopt;

  	int err;

  	if (opt == NULL || nla_len(opt) < sizeof(*qopt))

  		return -EINVAL;

  	qopt = nla_data(opt);

  	q->defcls = qopt->defcls;

  	err = qdisc_class_hash_init(&q->clhash);
  	if (err < 0)
  		return err;

  	q->eligible = RB_ROOT;
  	INIT_LIST_HEAD(&q->droplist);

  	q->root.cl_common.classid = sch->handle;

  	q->root.refcnt  = 1;

  	q->root.sched   = q;

  	q->root.qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,

  					  sch->handle);

  	if (q->root.qdisc == NULL)
  		q->root.qdisc = &noop_qdisc;

  	INIT_LIST_HEAD(&q->root.children);
  	q->root.vt_tree = RB_ROOT;
  	q->root.cf_tree = RB_ROOT;

  	qdisc_class_hash_insert(&q->clhash, &q->root.cl_common);
  	qdisc_class_hash_grow(sch, &q->clhash);

  	qdisc_watchdog_init(&q->watchdog, sch);

  
  	return 0;
  }
  
  static int

  hfsc_change_qdisc(struct Qdisc *sch, struct nlattr *opt)

  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct tc_hfsc_qopt *qopt;

  	if (opt == NULL || nla_len(opt) < sizeof(*qopt))

  		return -EINVAL;

  	qopt = nla_data(opt);

  
  	sch_tree_lock(sch);
  	q->defcls = qopt->defcls;
  	sch_tree_unlock(sch);
  
  	return 0;
  }
  
  static void
  hfsc_reset_class(struct hfsc_class *cl)
  {
  	cl->cl_total        = 0;
  	cl->cl_cumul        = 0;
  	cl->cl_d            = 0;
  	cl->cl_e            = 0;
  	cl->cl_vt           = 0;
  	cl->cl_vtadj        = 0;
  	cl->cl_vtoff        = 0;
  	cl->cl_cvtmin       = 0;
  	cl->cl_cvtmax       = 0;
  	cl->cl_cvtoff       = 0;
  	cl->cl_pcvtoff      = 0;
  	cl->cl_vtperiod     = 0;
  	cl->cl_parentperiod = 0;
  	cl->cl_f            = 0;
  	cl->cl_myf          = 0;
  	cl->cl_myfadj       = 0;
  	cl->cl_cfmin        = 0;
  	cl->cl_nactive      = 0;
  
  	cl->vt_tree = RB_ROOT;
  	cl->cf_tree = RB_ROOT;
  	qdisc_reset(cl->qdisc);
  
  	if (cl->cl_flags & HFSC_RSC)
  		rtsc_init(&cl->cl_deadline, &cl->cl_rsc, 0, 0);
  	if (cl->cl_flags & HFSC_FSC)
  		rtsc_init(&cl->cl_virtual, &cl->cl_fsc, 0, 0);
  	if (cl->cl_flags & HFSC_USC)
  		rtsc_init(&cl->cl_ulimit, &cl->cl_usc, 0, 0);
  }
  
  static void
  hfsc_reset_qdisc(struct Qdisc *sch)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl;

  	struct hlist_node *n;

  	unsigned int i;

  	for (i = 0; i < q->clhash.hashsize; i++) {
  		hlist_for_each_entry(cl, n, &q->clhash.hash[i], cl_common.hnode)

  			hfsc_reset_class(cl);
  	}

  	q->eligible = RB_ROOT;
  	INIT_LIST_HEAD(&q->droplist);

  	qdisc_watchdog_cancel(&q->watchdog);

  	sch->q.qlen = 0;
  }
  
  static void
  hfsc_destroy_qdisc(struct Qdisc *sch)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);

  	struct hlist_node *n, *next;
  	struct hfsc_class *cl;

  	unsigned int i;

  	for (i = 0; i < q->clhash.hashsize; i++) {
  		hlist_for_each_entry(cl, n, &q->clhash.hash[i], cl_common.hnode)

  			tcf_destroy_chain(&cl->filter_list);
  	}

  	for (i = 0; i < q->clhash.hashsize; i++) {
  		hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
  					  cl_common.hnode)

  			hfsc_destroy_class(sch, cl);
  	}

  	qdisc_class_hash_destroy(&q->clhash);

  	qdisc_watchdog_cancel(&q->watchdog);

  }
  
  static int
  hfsc_dump_qdisc(struct Qdisc *sch, struct sk_buff *skb)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);

  	unsigned char *b = skb_tail_pointer(skb);

  	struct tc_hfsc_qopt qopt;

  	struct hfsc_class *cl;
  	struct hlist_node *n;
  	unsigned int i;
  
  	sch->qstats.backlog = 0;
  	for (i = 0; i < q->clhash.hashsize; i++) {
  		hlist_for_each_entry(cl, n, &q->clhash.hash[i], cl_common.hnode)
  			sch->qstats.backlog += cl->qdisc->qstats.backlog;
  	}

  
  	qopt.defcls = q->defcls;

  	NLA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);

  	return skb->len;

   nla_put_failure:

  	nlmsg_trim(skb, b);

  	return -1;
  }
  
  static int
  hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  {
  	struct hfsc_class *cl;

  	int uninitialized_var(err);

  
  	cl = hfsc_classify(skb, sch, &err);
  	if (cl == NULL) {

  		if (err & __NET_XMIT_BYPASS)

  			sch->qstats.drops++;
  		kfree_skb(skb);
  		return err;
  	}

  	err = qdisc_enqueue(skb, cl->qdisc);

  	if (unlikely(err != NET_XMIT_SUCCESS)) {

  		if (net_xmit_drop_count(err)) {
  			cl->qstats.drops++;
  			sch->qstats.drops++;
  		}

  		return err;
  	}
  
  	if (cl->qdisc->q.qlen == 1)

  		set_active(cl, qdisc_pkt_len(skb));

  	bstats_update(&cl->bstats, skb);

  	sch->q.qlen++;
  
  	return NET_XMIT_SUCCESS;
  }
  
  static struct sk_buff *
  hfsc_dequeue(struct Qdisc *sch)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl;
  	struct sk_buff *skb;
  	u64 cur_time;
  	unsigned int next_len;
  	int realtime = 0;
  
  	if (sch->q.qlen == 0)
  		return NULL;

  	cur_time = psched_get_time();

  
  	/*
  	 * if there are eligible classes, use real-time criteria.
  	 * find the class with the minimum deadline among
  	 * the eligible classes.
  	 */

  	cl = eltree_get_mindl(q, cur_time);
  	if (cl) {

  		realtime = 1;
  	} else {
  		/*
  		 * use link-sharing criteria
  		 * get the class with the minimum vt in the hierarchy
  		 */
  		cl = vttree_get_minvt(&q->root, cur_time);
  		if (cl == NULL) {
  			sch->qstats.overlimits++;

  			hfsc_schedule_watchdog(sch);

  			return NULL;
  		}
  	}

  	skb = qdisc_dequeue_peeked(cl->qdisc);

  	if (skb == NULL) {

  		qdisc_warn_nonwc("HFSC", cl->qdisc);

  		return NULL;
  	}

  	update_vf(cl, qdisc_pkt_len(skb), cur_time);

  	if (realtime)

  		cl->cl_cumul += qdisc_pkt_len(skb);

  
  	if (cl->qdisc->q.qlen != 0) {
  		if (cl->cl_flags & HFSC_RSC) {
  			/* update ed */
  			next_len = qdisc_peek_len(cl->qdisc);
  			if (realtime)
  				update_ed(cl, next_len);
  			else
  				update_d(cl, next_len);
  		}
  	} else {
  		/* the class becomes passive */
  		set_passive(cl);
  	}

  	qdisc_unthrottled(sch);

  	qdisc_bstats_update(sch, skb);

  	sch->q.qlen--;
  
  	return skb;
  }

  static unsigned int
  hfsc_drop(struct Qdisc *sch)
  {
  	struct hfsc_sched *q = qdisc_priv(sch);
  	struct hfsc_class *cl;
  	unsigned int len;
  
  	list_for_each_entry(cl, &q->droplist, dlist) {
  		if (cl->qdisc->ops->drop != NULL &&
  		    (len = cl->qdisc->ops->drop(cl->qdisc)) > 0) {
  			if (cl->qdisc->q.qlen == 0) {
  				update_vf(cl, 0, 0);
  				set_passive(cl);
  			} else {
  				list_move_tail(&cl->dlist, &q->droplist);
  			}
  			cl->qstats.drops++;
  			sch->qstats.drops++;
  			sch->q.qlen--;
  			return len;
  		}
  	}
  	return 0;
  }

  static const struct Qdisc_class_ops hfsc_class_ops = {

  	.change		= hfsc_change_class,
  	.delete		= hfsc_delete_class,
  	.graft		= hfsc_graft_class,
  	.leaf		= hfsc_class_leaf,

  	.qlen_notify	= hfsc_qlen_notify,

  	.get		= hfsc_get_class,
  	.put		= hfsc_put_class,
  	.bind_tcf	= hfsc_bind_tcf,
  	.unbind_tcf	= hfsc_unbind_tcf,
  	.tcf_chain	= hfsc_tcf_chain,
  	.dump		= hfsc_dump_class,
  	.dump_stats	= hfsc_dump_class_stats,
  	.walk		= hfsc_walk
  };

  static struct Qdisc_ops hfsc_qdisc_ops __read_mostly = {

  	.id		= "hfsc",
  	.init		= hfsc_init_qdisc,
  	.change		= hfsc_change_qdisc,
  	.reset		= hfsc_reset_qdisc,
  	.destroy	= hfsc_destroy_qdisc,
  	.dump		= hfsc_dump_qdisc,
  	.enqueue	= hfsc_enqueue,
  	.dequeue	= hfsc_dequeue,

  	.peek		= qdisc_peek_dequeued,

  	.drop		= hfsc_drop,
  	.cl_ops		= &hfsc_class_ops,
  	.priv_size	= sizeof(struct hfsc_sched),
  	.owner		= THIS_MODULE
  };
  
  static int __init
  hfsc_init(void)
  {
  	return register_qdisc(&hfsc_qdisc_ops);
  }
  
  static void __exit
  hfsc_cleanup(void)
  {
  	unregister_qdisc(&hfsc_qdisc_ops);
  }
  
  MODULE_LICENSE("GPL");
  module_init(hfsc_init);
  module_exit(hfsc_cleanup);