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sch_hfsc.c

/*
 * 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 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
{
      u32         classid;    /* class id */
      unsigned int      refcnt;           /* usage count */

      struct gnet_stats_basic 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 hlist;       /* hash list 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 */
};

#define HFSC_HSIZE      16

struct hfsc_sched
{
      u16   defcls;                       /* default class id */
      struct hfsc_class root;             /* root class */
      struct list_head clhash[HFSC_HSIZE];      /* class hash */
      struct rb_root eligible;            /* eligible tree */
      struct list_head droplist;          /* active leaf class list (for
                                       dropping) */
      struct sk_buff_head requeue;        /* requeued packet */
      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 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
 */
#define     SM_SHIFT    20
#define     ISM_SHIFT   18

#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;
      return;
}

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.
       */
}

/*
 * hack to get length of first packet in queue.
 */
static unsigned int
qdisc_peek_len(struct Qdisc *sch)
{
      struct sk_buff *skb;
      unsigned int len;

      skb = sch->dequeue(sch);
      if (skb == NULL) {
            if (net_ratelimit())
                  printk("qdisc_peek_len: non work-conserving qdisc ?\n");
            return 0;
      }
      len = skb->len;
      if (unlikely(sch->ops->requeue(skb, sch) != NET_XMIT_SUCCESS)) {
            if (net_ratelimit())
                  printk("qdisc_peek_len: failed to requeue\n");
            qdisc_tree_decrease_qlen(sch, 1);
            return 0;
      }
      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 unsigned int
hfsc_hash(u32 h)
{
      h ^= h >> 8;
      h ^= h >> 4;

      return h & (HFSC_HSIZE - 1);
}

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

      list_for_each_entry(cl, &q->clhash[hfsc_hash(classid)], hlist) {
            if (cl->classid == classid)
                  return cl;
      }
      return NULL;
}

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 int
hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
              struct rtattr **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 rtattr *opt = tca[TCA_OPTIONS-1];
      struct rtattr *tb[TCA_HFSC_MAX];
      struct tc_service_curve *rsc = NULL, *fsc = NULL, *usc = NULL;
      u64 cur_time;

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

      if (tb[TCA_HFSC_RSC-1]) {
            if (RTA_PAYLOAD(tb[TCA_HFSC_RSC-1]) < sizeof(*rsc))
                  return -EINVAL;
            rsc = RTA_DATA(tb[TCA_HFSC_RSC-1]);
            if (rsc->m1 == 0 && rsc->m2 == 0)
                  rsc = NULL;
      }

      if (tb[TCA_HFSC_FSC-1]) {
            if (RTA_PAYLOAD(tb[TCA_HFSC_FSC-1]) < sizeof(*fsc))
                  return -EINVAL;
            fsc = RTA_DATA(tb[TCA_HFSC_FSC-1]);
            if (fsc->m1 == 0 && fsc->m2 == 0)
                  fsc = NULL;
      }

      if (tb[TCA_HFSC_USC-1]) {
            if (RTA_PAYLOAD(tb[TCA_HFSC_USC-1]) < sizeof(*usc))
                  return -EINVAL;
            usc = RTA_DATA(tb[TCA_HFSC_USC-1]);
            if (usc->m1 == 0 && usc->m2 == 0)
                  usc = NULL;
      }

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

            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);

            if (tca[TCA_RATE-1])
                  gen_replace_estimator(&cl->bstats, &cl->rate_est,
                                    &sch->dev->queue_lock,
                                    tca[TCA_RATE-1]);
            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 (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->refcnt    = 1;
      cl->classid   = classid;
      cl->sched     = q;
      cl->cl_parent = parent;
      cl->qdisc = qdisc_create_dflt(sch->dev, &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);
      list_add_tail(&cl->hlist, &q->clhash[hfsc_hash(classid)]);
      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);

      if (tca[TCA_RATE-1])
            gen_new_estimator(&cl->bstats, &cl->rate_est,
                          &sch->dev->queue_lock, tca[TCA_RATE-1]);
      *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);
      list_del(&cl->hlist);

      if (--cl->refcnt == 0)
            hfsc_destroy_class(sch, cl);

      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 *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_BYPASS;
      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;
            case TC_ACT_SHOT:
                  return NULL;
            }
#endif
            if ((cl = (struct hfsc_class *)res.class) == NULL) {
                  if ((cl = hfsc_find_class(res.classid, sch)) == NULL)
                        break; /* filter selected invalid classid */
            }

            if (cl->level == 0)
                  return cl; /* hit leaf class */

            /* apply inner filter chain */
            tcf = cl->filter_list;
      }

      /* 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 == NULL)
            return -ENOENT;
      if (cl->level > 0)
            return -EINVAL;
      if (new == NULL) {
            new = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
                              cl->classid);
            if (new == NULL)
                  new = &noop_qdisc;
      }

      sch_tree_lock(sch);
      hfsc_purge_queue(sch, cl);
      *old = xchg(&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 != NULL && 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);
      RTA_PUT(skb, attr, sizeof(tsc), &tsc);

      return skb->len;

 rtattr_failure:
      return -1;
}

static inline 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 rtattr_failure;

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

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

      return skb->len;

 rtattr_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;
      unsigned char *b = skb_tail_pointer(skb);
      struct rtattr *rta = (struct rtattr *)b;

      tcm->tcm_parent = cl->cl_parent ? cl->cl_parent->classid : TC_H_ROOT;
      tcm->tcm_handle = cl->classid;
      if (cl->level == 0)
            tcm->tcm_info = cl->qdisc->handle;

      RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
      if (hfsc_dump_curves(skb, cl) < 0)
            goto rtattr_failure;
      rta->rta_len = skb_tail_pointer(skb) - b;
      return skb->len;

 rtattr_failure:
      nlmsg_trim(skb, b);
      return -1;
}

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;
      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->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 hfsc_class *cl;
      unsigned int i;

      if (arg->stop)
            return;

      for (i = 0; i < HFSC_HSIZE; i++) {
            list_for_each_entry(cl, &q->clhash[i], hlist) {
                  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;

      if ((cl = eltree_get_minel(q)) != NULL)
            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 rtattr *opt)
{
      struct hfsc_sched *q = qdisc_priv(sch);
      struct tc_hfsc_qopt *qopt;
      unsigned int i;

      if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(*qopt))
            return -EINVAL;
      qopt = RTA_DATA(opt);

      q->defcls = qopt->defcls;
      for (i = 0; i < HFSC_HSIZE; i++)
            INIT_LIST_HEAD(&q->clhash[i]);
      q->eligible = RB_ROOT;
      INIT_LIST_HEAD(&q->droplist);
      skb_queue_head_init(&q->requeue);

      q->root.refcnt  = 1;
      q->root.classid = sch->handle;
      q->root.sched   = q;
      q->root.qdisc = qdisc_create_dflt(sch->dev, &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;

      list_add(&q->root.hlist, &q->clhash[hfsc_hash(q->root.classid)]);

      qdisc_watchdog_init(&q->watchdog, sch);

      return 0;
}

static int
hfsc_change_qdisc(struct Qdisc *sch, struct rtattr *opt)
{
      struct hfsc_sched *q = qdisc_priv(sch);
      struct tc_hfsc_qopt *qopt;

      if (opt == NULL || RTA_PAYLOAD(opt) < sizeof(*qopt))
            return -EINVAL;
      qopt = RTA_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;
      unsigned int i;

      for (i = 0; i < HFSC_HSIZE; i++) {
            list_for_each_entry(cl, &q->clhash[i], hlist)
                  hfsc_reset_class(cl);
      }
      __skb_queue_purge(&q->requeue);
      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 hfsc_class *cl, *next;
      unsigned int i;

      for (i = 0; i < HFSC_HSIZE; i++) {
            list_for_each_entry_safe(cl, next, &q->clhash[i], hlist)
                  hfsc_destroy_class(sch, cl);
      }
      __skb_queue_purge(&q->requeue);
      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;

      qopt.defcls = q->defcls;
      RTA_PUT(skb, TCA_OPTIONS, sizeof(qopt), &qopt);
      return skb->len;

 rtattr_failure:
      nlmsg_trim(skb, b);
      return -1;
}

static int
hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
      struct hfsc_class *cl;
      unsigned int len;
      int err;

      cl = hfsc_classify(skb, sch, &err);
      if (cl == NULL) {
            if (err == NET_XMIT_BYPASS)
                  sch->qstats.drops++;
            kfree_skb(skb);
            return err;
      }

      len = skb->len;
      err = cl->qdisc->enqueue(skb, cl->qdisc);
      if (unlikely(err != NET_XMIT_SUCCESS)) {
            cl->qstats.drops++;
            sch->qstats.drops++;
            return err;
      }

      if (cl->qdisc->q.qlen == 1)
            set_active(cl, len);

      cl->bstats.packets++;
      cl->bstats.bytes += len;
      sch->bstats.packets++;
      sch->bstats.bytes += len;
      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;
      if ((skb = __skb_dequeue(&q->requeue)))
            goto out;

      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.
       */
      if ((cl = eltree_get_mindl(q, cur_time)) != NULL) {
            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 = cl->qdisc->dequeue(cl->qdisc);
      if (skb == NULL) {
            if (net_ratelimit())
                  printk("HFSC: Non-work-conserving qdisc ?\n");
            return NULL;
      }

      update_vf(cl, skb->len, cur_time);
      if (realtime)
            cl->cl_cumul += skb->len;

      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);
      }

 out:
      sch->flags &= ~TCQ_F_THROTTLED;
      sch->q.qlen--;

      return skb;
}

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

      __skb_queue_head(&q->requeue, skb);
      sch->q.qlen++;
      sch->qstats.requeues++;
      return NET_XMIT_SUCCESS;
}

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 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 = {
      .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,
      .requeue    = hfsc_requeue,
      .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);

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