Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/net/sched/sch_htb.c

  1 /*
  2  * net/sched/sch_htb.c  Hierarchical token bucket, feed tree version
  3  *
  4  *              This program is free software; you can redistribute it and/or
  5  *              modify it under the terms of the GNU General Public License
  6  *              as published by the Free Software Foundation; either version
  7  *              2 of the License, or (at your option) any later version.
  8  *
  9  * Authors:     Martin Devera, <devik@cdi.cz>
 10  *
 11  * Credits (in time order) for older HTB versions:
 12  *              Stef Coene <stef.coene@docum.org>
 13  *                      HTB support at LARTC mailing list
 14  *              Ondrej Kraus, <krauso@barr.cz>
 15  *                      found missing INIT_QDISC(htb)
 16  *              Vladimir Smelhaus, Aamer Akhter, Bert Hubert
 17  *                      helped a lot to locate nasty class stall bug
 18  *              Andi Kleen, Jamal Hadi, Bert Hubert
 19  *                      code review and helpful comments on shaping
 20  *              Tomasz Wrona, <tw@eter.tym.pl>
 21  *                      created test case so that I was able to fix nasty bug
 22  *              Wilfried Weissmann
 23  *                      spotted bug in dequeue code and helped with fix
 24  *              Jiri Fojtasek
 25  *                      fixed requeue routine
 26  *              and many others. thanks.
 27  */
 28 #include <linux/module.h>
 29 #include <linux/moduleparam.h>
 30 #include <linux/types.h>
 31 #include <linux/kernel.h>
 32 #include <linux/string.h>
 33 #include <linux/errno.h>
 34 #include <linux/skbuff.h>
 35 #include <linux/list.h>
 36 #include <linux/compiler.h>
 37 #include <linux/rbtree.h>
 38 #include <linux/workqueue.h>
 39 #include <linux/slab.h>
 40 #include <net/netlink.h>
 41 #include <net/sch_generic.h>
 42 #include <net/pkt_sched.h>
 43 
 44 /* HTB algorithm.
 45     Author: devik@cdi.cz
 46     ========================================================================
 47     HTB is like TBF with multiple classes. It is also similar to CBQ because
 48     it allows to assign priority to each class in hierarchy.
 49     In fact it is another implementation of Floyd's formal sharing.
 50 
 51     Levels:
 52     Each class is assigned level. Leaf has ALWAYS level 0 and root
 53     classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level
 54     one less than their parent.
 55 */
 56 
 57 static int htb_hysteresis __read_mostly = 0; /* whether to use mode hysteresis for speedup */
 58 #define HTB_VER 0x30011         /* major must be matched with number suplied by TC as version */
 59 
 60 #if HTB_VER >> 16 != TC_HTB_PROTOVER
 61 #error "Mismatched sch_htb.c and pkt_sch.h"
 62 #endif
 63 
 64 /* Module parameter and sysfs export */
 65 module_param    (htb_hysteresis, int, 0640);
 66 MODULE_PARM_DESC(htb_hysteresis, "Hysteresis mode, less CPU load, less accurate");
 67 
 68 static int htb_rate_est = 0; /* htb classes have a default rate estimator */
 69 module_param(htb_rate_est, int, 0640);
 70 MODULE_PARM_DESC(htb_rate_est, "setup a default rate estimator (4sec 16sec) for htb classes");
 71 
 72 /* used internaly to keep status of single class */
 73 enum htb_cmode {
 74         HTB_CANT_SEND,          /* class can't send and can't borrow */
 75         HTB_MAY_BORROW,         /* class can't send but may borrow */
 76         HTB_CAN_SEND            /* class can send */
 77 };
 78 
 79 struct htb_prio {
 80         union {
 81                 struct rb_root  row;
 82                 struct rb_root  feed;
 83         };
 84         struct rb_node  *ptr;
 85         /* When class changes from state 1->2 and disconnects from
 86          * parent's feed then we lost ptr value and start from the
 87          * first child again. Here we store classid of the
 88          * last valid ptr (used when ptr is NULL).
 89          */
 90         u32             last_ptr_id;
 91 };
 92 
 93 /* interior & leaf nodes; props specific to leaves are marked L:
 94  * To reduce false sharing, place mostly read fields at beginning,
 95  * and mostly written ones at the end.
 96  */
 97 struct htb_class {
 98         struct Qdisc_class_common common;
 99         struct psched_ratecfg   rate;
100         struct psched_ratecfg   ceil;
101         s64                     buffer, cbuffer;/* token bucket depth/rate */
102         s64                     mbuffer;        /* max wait time */
103         u32                     prio;           /* these two are used only by leaves... */
104         int                     quantum;        /* but stored for parent-to-leaf return */
105 
106         struct tcf_proto __rcu  *filter_list;   /* class attached filters */
107         int                     filter_cnt;
108         int                     refcnt;         /* usage count of this class */
109 
110         int                     level;          /* our level (see above) */
111         unsigned int            children;
112         struct htb_class        *parent;        /* parent class */
113 
114         struct net_rate_estimator __rcu *rate_est;
115 
116         /*
117          * Written often fields
118          */
119         struct gnet_stats_basic_packed bstats;
120         struct tc_htb_xstats    xstats; /* our special stats */
121 
122         /* token bucket parameters */
123         s64                     tokens, ctokens;/* current number of tokens */
124         s64                     t_c;            /* checkpoint time */
125 
126         union {
127                 struct htb_class_leaf {
128                         struct list_head drop_list;
129                         int             deficit[TC_HTB_MAXDEPTH];
130                         struct Qdisc    *q;
131                 } leaf;
132                 struct htb_class_inner {
133                         struct htb_prio clprio[TC_HTB_NUMPRIO];
134                 } inner;
135         } un;
136         s64                     pq_key;
137 
138         int                     prio_activity;  /* for which prios are we active */
139         enum htb_cmode          cmode;          /* current mode of the class */
140         struct rb_node          pq_node;        /* node for event queue */
141         struct rb_node          node[TC_HTB_NUMPRIO];   /* node for self or feed tree */
142 
143         unsigned int drops ____cacheline_aligned_in_smp;
144 };
145 
146 struct htb_level {
147         struct rb_root  wait_pq;
148         struct htb_prio hprio[TC_HTB_NUMPRIO];
149 };
150 
151 struct htb_sched {
152         struct Qdisc_class_hash clhash;
153         int                     defcls;         /* class where unclassified flows go to */
154         int                     rate2quantum;   /* quant = rate / rate2quantum */
155 
156         /* filters for qdisc itself */
157         struct tcf_proto __rcu  *filter_list;
158 
159 #define HTB_WARN_TOOMANYEVENTS  0x1
160         unsigned int            warned; /* only one warning */
161         int                     direct_qlen;
162         struct work_struct      work;
163 
164         /* non shaped skbs; let them go directly thru */
165         struct qdisc_skb_head   direct_queue;
166         long                    direct_pkts;
167 
168         struct qdisc_watchdog   watchdog;
169 
170         s64                     now;    /* cached dequeue time */
171         struct list_head        drops[TC_HTB_NUMPRIO];/* active leaves (for drops) */
172 
173         /* time of nearest event per level (row) */
174         s64                     near_ev_cache[TC_HTB_MAXDEPTH];
175 
176         int                     row_mask[TC_HTB_MAXDEPTH];
177 
178         struct htb_level        hlevel[TC_HTB_MAXDEPTH];
179 };
180 
181 /* find class in global hash table using given handle */
182 static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
183 {
184         struct htb_sched *q = qdisc_priv(sch);
185         struct Qdisc_class_common *clc;
186 
187         clc = qdisc_class_find(&q->clhash, handle);
188         if (clc == NULL)
189                 return NULL;
190         return container_of(clc, struct htb_class, common);
191 }
192 
193 /**
194  * htb_classify - classify a packet into class
195  *
196  * It returns NULL if the packet should be dropped or -1 if the packet
197  * should be passed directly thru. In all other cases leaf class is returned.
198  * We allow direct class selection by classid in priority. The we examine
199  * filters in qdisc and in inner nodes (if higher filter points to the inner
200  * node). If we end up with classid MAJOR:0 we enqueue the skb into special
201  * internal fifo (direct). These packets then go directly thru. If we still
202  * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessful
203  * then finish and return direct queue.
204  */
205 #define HTB_DIRECT ((struct htb_class *)-1L)
206 
207 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
208                                       int *qerr)
209 {
210         struct htb_sched *q = qdisc_priv(sch);
211         struct htb_class *cl;
212         struct tcf_result res;
213         struct tcf_proto *tcf;
214         int result;
215 
216         /* allow to select class by setting skb->priority to valid classid;
217          * note that nfmark can be used too by attaching filter fw with no
218          * rules in it
219          */
220         if (skb->priority == sch->handle)
221                 return HTB_DIRECT;      /* X:0 (direct flow) selected */
222         cl = htb_find(skb->priority, sch);
223         if (cl) {
224                 if (cl->level == 0)
225                         return cl;
226                 /* Start with inner filter chain if a non-leaf class is selected */
227                 tcf = rcu_dereference_bh(cl->filter_list);
228         } else {
229                 tcf = rcu_dereference_bh(q->filter_list);
230         }
231 
232         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
233         while (tcf && (result = tc_classify(skb, tcf, &res, false)) >= 0) {
234 #ifdef CONFIG_NET_CLS_ACT
235                 switch (result) {
236                 case TC_ACT_QUEUED:
237                 case TC_ACT_STOLEN:
238                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
239                 case TC_ACT_SHOT:
240                         return NULL;
241                 }
242 #endif
243                 cl = (void *)res.class;
244                 if (!cl) {
245                         if (res.classid == sch->handle)
246                                 return HTB_DIRECT;      /* X:0 (direct flow) */
247                         cl = htb_find(res.classid, sch);
248                         if (!cl)
249                                 break;  /* filter selected invalid classid */
250                 }
251                 if (!cl->level)
252                         return cl;      /* we hit leaf; return it */
253 
254                 /* we have got inner class; apply inner filter chain */
255                 tcf = rcu_dereference_bh(cl->filter_list);
256         }
257         /* classification failed; try to use default class */
258         cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
259         if (!cl || cl->level)
260                 return HTB_DIRECT;      /* bad default .. this is safe bet */
261         return cl;
262 }
263 
264 /**
265  * htb_add_to_id_tree - adds class to the round robin list
266  *
267  * Routine adds class to the list (actually tree) sorted by classid.
268  * Make sure that class is not already on such list for given prio.
269  */
270 static void htb_add_to_id_tree(struct rb_root *root,
271                                struct htb_class *cl, int prio)
272 {
273         struct rb_node **p = &root->rb_node, *parent = NULL;
274 
275         while (*p) {
276                 struct htb_class *c;
277                 parent = *p;
278                 c = rb_entry(parent, struct htb_class, node[prio]);
279 
280                 if (cl->common.classid > c->common.classid)
281                         p = &parent->rb_right;
282                 else
283                         p = &parent->rb_left;
284         }
285         rb_link_node(&cl->node[prio], parent, p);
286         rb_insert_color(&cl->node[prio], root);
287 }
288 
289 /**
290  * htb_add_to_wait_tree - adds class to the event queue with delay
291  *
292  * The class is added to priority event queue to indicate that class will
293  * change its mode in cl->pq_key microseconds. Make sure that class is not
294  * already in the queue.
295  */
296 static void htb_add_to_wait_tree(struct htb_sched *q,
297                                  struct htb_class *cl, s64 delay)
298 {
299         struct rb_node **p = &q->hlevel[cl->level].wait_pq.rb_node, *parent = NULL;
300 
301         cl->pq_key = q->now + delay;
302         if (cl->pq_key == q->now)
303                 cl->pq_key++;
304 
305         /* update the nearest event cache */
306         if (q->near_ev_cache[cl->level] > cl->pq_key)
307                 q->near_ev_cache[cl->level] = cl->pq_key;
308 
309         while (*p) {
310                 struct htb_class *c;
311                 parent = *p;
312                 c = rb_entry(parent, struct htb_class, pq_node);
313                 if (cl->pq_key >= c->pq_key)
314                         p = &parent->rb_right;
315                 else
316                         p = &parent->rb_left;
317         }
318         rb_link_node(&cl->pq_node, parent, p);
319         rb_insert_color(&cl->pq_node, &q->hlevel[cl->level].wait_pq);
320 }
321 
322 /**
323  * htb_next_rb_node - finds next node in binary tree
324  *
325  * When we are past last key we return NULL.
326  * Average complexity is 2 steps per call.
327  */
328 static inline void htb_next_rb_node(struct rb_node **n)
329 {
330         *n = rb_next(*n);
331 }
332 
333 /**
334  * htb_add_class_to_row - add class to its row
335  *
336  * The class is added to row at priorities marked in mask.
337  * It does nothing if mask == 0.
338  */
339 static inline void htb_add_class_to_row(struct htb_sched *q,
340                                         struct htb_class *cl, int mask)
341 {
342         q->row_mask[cl->level] |= mask;
343         while (mask) {
344                 int prio = ffz(~mask);
345                 mask &= ~(1 << prio);
346                 htb_add_to_id_tree(&q->hlevel[cl->level].hprio[prio].row, cl, prio);
347         }
348 }
349 
350 /* If this triggers, it is a bug in this code, but it need not be fatal */
351 static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root)
352 {
353         if (RB_EMPTY_NODE(rb)) {
354                 WARN_ON(1);
355         } else {
356                 rb_erase(rb, root);
357                 RB_CLEAR_NODE(rb);
358         }
359 }
360 
361 
362 /**
363  * htb_remove_class_from_row - removes class from its row
364  *
365  * The class is removed from row at priorities marked in mask.
366  * It does nothing if mask == 0.
367  */
368 static inline void htb_remove_class_from_row(struct htb_sched *q,
369                                                  struct htb_class *cl, int mask)
370 {
371         int m = 0;
372         struct htb_level *hlevel = &q->hlevel[cl->level];
373 
374         while (mask) {
375                 int prio = ffz(~mask);
376                 struct htb_prio *hprio = &hlevel->hprio[prio];
377 
378                 mask &= ~(1 << prio);
379                 if (hprio->ptr == cl->node + prio)
380                         htb_next_rb_node(&hprio->ptr);
381 
382                 htb_safe_rb_erase(cl->node + prio, &hprio->row);
383                 if (!hprio->row.rb_node)
384                         m |= 1 << prio;
385         }
386         q->row_mask[cl->level] &= ~m;
387 }
388 
389 /**
390  * htb_activate_prios - creates active classe's feed chain
391  *
392  * The class is connected to ancestors and/or appropriate rows
393  * for priorities it is participating on. cl->cmode must be new
394  * (activated) mode. It does nothing if cl->prio_activity == 0.
395  */
396 static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
397 {
398         struct htb_class *p = cl->parent;
399         long m, mask = cl->prio_activity;
400 
401         while (cl->cmode == HTB_MAY_BORROW && p && mask) {
402                 m = mask;
403                 while (m) {
404                         int prio = ffz(~m);
405                         m &= ~(1 << prio);
406 
407                         if (p->un.inner.clprio[prio].feed.rb_node)
408                                 /* parent already has its feed in use so that
409                                  * reset bit in mask as parent is already ok
410                                  */
411                                 mask &= ~(1 << prio);
412 
413                         htb_add_to_id_tree(&p->un.inner.clprio[prio].feed, cl, prio);
414                 }
415                 p->prio_activity |= mask;
416                 cl = p;
417                 p = cl->parent;
418 
419         }
420         if (cl->cmode == HTB_CAN_SEND && mask)
421                 htb_add_class_to_row(q, cl, mask);
422 }
423 
424 /**
425  * htb_deactivate_prios - remove class from feed chain
426  *
427  * cl->cmode must represent old mode (before deactivation). It does
428  * nothing if cl->prio_activity == 0. Class is removed from all feed
429  * chains and rows.
430  */
431 static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
432 {
433         struct htb_class *p = cl->parent;
434         long m, mask = cl->prio_activity;
435 
436         while (cl->cmode == HTB_MAY_BORROW && p && mask) {
437                 m = mask;
438                 mask = 0;
439                 while (m) {
440                         int prio = ffz(~m);
441                         m &= ~(1 << prio);
442 
443                         if (p->un.inner.clprio[prio].ptr == cl->node + prio) {
444                                 /* we are removing child which is pointed to from
445                                  * parent feed - forget the pointer but remember
446                                  * classid
447                                  */
448                                 p->un.inner.clprio[prio].last_ptr_id = cl->common.classid;
449                                 p->un.inner.clprio[prio].ptr = NULL;
450                         }
451 
452                         htb_safe_rb_erase(cl->node + prio,
453                                           &p->un.inner.clprio[prio].feed);
454 
455                         if (!p->un.inner.clprio[prio].feed.rb_node)
456                                 mask |= 1 << prio;
457                 }
458 
459                 p->prio_activity &= ~mask;
460                 cl = p;
461                 p = cl->parent;
462 
463         }
464         if (cl->cmode == HTB_CAN_SEND && mask)
465                 htb_remove_class_from_row(q, cl, mask);
466 }
467 
468 static inline s64 htb_lowater(const struct htb_class *cl)
469 {
470         if (htb_hysteresis)
471                 return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
472         else
473                 return 0;
474 }
475 static inline s64 htb_hiwater(const struct htb_class *cl)
476 {
477         if (htb_hysteresis)
478                 return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
479         else
480                 return 0;
481 }
482 
483 
484 /**
485  * htb_class_mode - computes and returns current class mode
486  *
487  * It computes cl's mode at time cl->t_c+diff and returns it. If mode
488  * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
489  * from now to time when cl will change its state.
490  * Also it is worth to note that class mode doesn't change simply
491  * at cl->{c,}tokens == 0 but there can rather be hysteresis of
492  * 0 .. -cl->{c,}buffer range. It is meant to limit number of
493  * mode transitions per time unit. The speed gain is about 1/6.
494  */
495 static inline enum htb_cmode
496 htb_class_mode(struct htb_class *cl, s64 *diff)
497 {
498         s64 toks;
499 
500         if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
501                 *diff = -toks;
502                 return HTB_CANT_SEND;
503         }
504 
505         if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
506                 return HTB_CAN_SEND;
507 
508         *diff = -toks;
509         return HTB_MAY_BORROW;
510 }
511 
512 /**
513  * htb_change_class_mode - changes classe's mode
514  *
515  * This should be the only way how to change classe's mode under normal
516  * cirsumstances. Routine will update feed lists linkage, change mode
517  * and add class to the wait event queue if appropriate. New mode should
518  * be different from old one and cl->pq_key has to be valid if changing
519  * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
520  */
521 static void
522 htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, s64 *diff)
523 {
524         enum htb_cmode new_mode = htb_class_mode(cl, diff);
525 
526         if (new_mode == cl->cmode)
527                 return;
528 
529         if (cl->prio_activity) {        /* not necessary: speed optimization */
530                 if (cl->cmode != HTB_CANT_SEND)
531                         htb_deactivate_prios(q, cl);
532                 cl->cmode = new_mode;
533                 if (new_mode != HTB_CANT_SEND)
534                         htb_activate_prios(q, cl);
535         } else
536                 cl->cmode = new_mode;
537 }
538 
539 /**
540  * htb_activate - inserts leaf cl into appropriate active feeds
541  *
542  * Routine learns (new) priority of leaf and activates feed chain
543  * for the prio. It can be called on already active leaf safely.
544  * It also adds leaf into droplist.
545  */
546 static inline void htb_activate(struct htb_sched *q, struct htb_class *cl)
547 {
548         WARN_ON(cl->level || !cl->un.leaf.q || !cl->un.leaf.q->q.qlen);
549 
550         if (!cl->prio_activity) {
551                 cl->prio_activity = 1 << cl->prio;
552                 htb_activate_prios(q, cl);
553                 list_add_tail(&cl->un.leaf.drop_list,
554                               q->drops + cl->prio);
555         }
556 }
557 
558 /**
559  * htb_deactivate - remove leaf cl from active feeds
560  *
561  * Make sure that leaf is active. In the other words it can't be called
562  * with non-active leaf. It also removes class from the drop list.
563  */
564 static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl)
565 {
566         WARN_ON(!cl->prio_activity);
567 
568         htb_deactivate_prios(q, cl);
569         cl->prio_activity = 0;
570         list_del_init(&cl->un.leaf.drop_list);
571 }
572 
573 static void htb_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
574                              struct qdisc_skb_head *qh)
575 {
576         struct sk_buff *last = qh->tail;
577 
578         if (last) {
579                 skb->next = NULL;
580                 last->next = skb;
581                 qh->tail = skb;
582         } else {
583                 qh->tail = skb;
584                 qh->head = skb;
585         }
586         qh->qlen++;
587 }
588 
589 static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
590                        struct sk_buff **to_free)
591 {
592         int uninitialized_var(ret);
593         struct htb_sched *q = qdisc_priv(sch);
594         struct htb_class *cl = htb_classify(skb, sch, &ret);
595 
596         if (cl == HTB_DIRECT) {
597                 /* enqueue to helper queue */
598                 if (q->direct_queue.qlen < q->direct_qlen) {
599                         htb_enqueue_tail(skb, sch, &q->direct_queue);
600                         q->direct_pkts++;
601                 } else {
602                         return qdisc_drop(skb, sch, to_free);
603                 }
604 #ifdef CONFIG_NET_CLS_ACT
605         } else if (!cl) {
606                 if (ret & __NET_XMIT_BYPASS)
607                         qdisc_qstats_drop(sch);
608                 __qdisc_drop(skb, to_free);
609                 return ret;
610 #endif
611         } else if ((ret = qdisc_enqueue(skb, cl->un.leaf.q,
612                                         to_free)) != NET_XMIT_SUCCESS) {
613                 if (net_xmit_drop_count(ret)) {
614                         qdisc_qstats_drop(sch);
615                         cl->drops++;
616                 }
617                 return ret;
618         } else {
619                 htb_activate(q, cl);
620         }
621 
622         qdisc_qstats_backlog_inc(sch, skb);
623         sch->q.qlen++;
624         return NET_XMIT_SUCCESS;
625 }
626 
627 static inline void htb_accnt_tokens(struct htb_class *cl, int bytes, s64 diff)
628 {
629         s64 toks = diff + cl->tokens;
630 
631         if (toks > cl->buffer)
632                 toks = cl->buffer;
633         toks -= (s64) psched_l2t_ns(&cl->rate, bytes);
634         if (toks <= -cl->mbuffer)
635                 toks = 1 - cl->mbuffer;
636 
637         cl->tokens = toks;
638 }
639 
640 static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff)
641 {
642         s64 toks = diff + cl->ctokens;
643 
644         if (toks > cl->cbuffer)
645                 toks = cl->cbuffer;
646         toks -= (s64) psched_l2t_ns(&cl->ceil, bytes);
647         if (toks <= -cl->mbuffer)
648                 toks = 1 - cl->mbuffer;
649 
650         cl->ctokens = toks;
651 }
652 
653 /**
654  * htb_charge_class - charges amount "bytes" to leaf and ancestors
655  *
656  * Routine assumes that packet "bytes" long was dequeued from leaf cl
657  * borrowing from "level". It accounts bytes to ceil leaky bucket for
658  * leaf and all ancestors and to rate bucket for ancestors at levels
659  * "level" and higher. It also handles possible change of mode resulting
660  * from the update. Note that mode can also increase here (MAY_BORROW to
661  * CAN_SEND) because we can use more precise clock that event queue here.
662  * In such case we remove class from event queue first.
663  */
664 static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
665                              int level, struct sk_buff *skb)
666 {
667         int bytes = qdisc_pkt_len(skb);
668         enum htb_cmode old_mode;
669         s64 diff;
670 
671         while (cl) {
672                 diff = min_t(s64, q->now - cl->t_c, cl->mbuffer);
673                 if (cl->level >= level) {
674                         if (cl->level == level)
675                                 cl->xstats.lends++;
676                         htb_accnt_tokens(cl, bytes, diff);
677                 } else {
678                         cl->xstats.borrows++;
679                         cl->tokens += diff;     /* we moved t_c; update tokens */
680                 }
681                 htb_accnt_ctokens(cl, bytes, diff);
682                 cl->t_c = q->now;
683 
684                 old_mode = cl->cmode;
685                 diff = 0;
686                 htb_change_class_mode(q, cl, &diff);
687                 if (old_mode != cl->cmode) {
688                         if (old_mode != HTB_CAN_SEND)
689                                 htb_safe_rb_erase(&cl->pq_node, &q->hlevel[cl->level].wait_pq);
690                         if (cl->cmode != HTB_CAN_SEND)
691                                 htb_add_to_wait_tree(q, cl, diff);
692                 }
693 
694                 /* update basic stats except for leaves which are already updated */
695                 if (cl->level)
696                         bstats_update(&cl->bstats, skb);
697 
698                 cl = cl->parent;
699         }
700 }
701 
702 /**
703  * htb_do_events - make mode changes to classes at the level
704  *
705  * Scans event queue for pending events and applies them. Returns time of
706  * next pending event (0 for no event in pq, q->now for too many events).
707  * Note: Applied are events whose have cl->pq_key <= q->now.
708  */
709 static s64 htb_do_events(struct htb_sched *q, const int level,
710                          unsigned long start)
711 {
712         /* don't run for longer than 2 jiffies; 2 is used instead of
713          * 1 to simplify things when jiffy is going to be incremented
714          * too soon
715          */
716         unsigned long stop_at = start + 2;
717         struct rb_root *wait_pq = &q->hlevel[level].wait_pq;
718 
719         while (time_before(jiffies, stop_at)) {
720                 struct htb_class *cl;
721                 s64 diff;
722                 struct rb_node *p = rb_first(wait_pq);
723 
724                 if (!p)
725                         return 0;
726 
727                 cl = rb_entry(p, struct htb_class, pq_node);
728                 if (cl->pq_key > q->now)
729                         return cl->pq_key;
730 
731                 htb_safe_rb_erase(p, wait_pq);
732                 diff = min_t(s64, q->now - cl->t_c, cl->mbuffer);
733                 htb_change_class_mode(q, cl, &diff);
734                 if (cl->cmode != HTB_CAN_SEND)
735                         htb_add_to_wait_tree(q, cl, diff);
736         }
737 
738         /* too much load - let's continue after a break for scheduling */
739         if (!(q->warned & HTB_WARN_TOOMANYEVENTS)) {
740                 pr_warn("htb: too many events!\n");
741                 q->warned |= HTB_WARN_TOOMANYEVENTS;
742         }
743 
744         return q->now;
745 }
746 
747 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
748  * is no such one exists.
749  */
750 static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n,
751                                               u32 id)
752 {
753         struct rb_node *r = NULL;
754         while (n) {
755                 struct htb_class *cl =
756                     rb_entry(n, struct htb_class, node[prio]);
757 
758                 if (id > cl->common.classid) {
759                         n = n->rb_right;
760                 } else if (id < cl->common.classid) {
761                         r = n;
762                         n = n->rb_left;
763                 } else {
764                         return n;
765                 }
766         }
767         return r;
768 }
769 
770 /**
771  * htb_lookup_leaf - returns next leaf class in DRR order
772  *
773  * Find leaf where current feed pointers points to.
774  */
775 static struct htb_class *htb_lookup_leaf(struct htb_prio *hprio, const int prio)
776 {
777         int i;
778         struct {
779                 struct rb_node *root;
780                 struct rb_node **pptr;
781                 u32 *pid;
782         } stk[TC_HTB_MAXDEPTH], *sp = stk;
783 
784         BUG_ON(!hprio->row.rb_node);
785         sp->root = hprio->row.rb_node;
786         sp->pptr = &hprio->ptr;
787         sp->pid = &hprio->last_ptr_id;
788 
789         for (i = 0; i < 65535; i++) {
790                 if (!*sp->pptr && *sp->pid) {
791                         /* ptr was invalidated but id is valid - try to recover
792                          * the original or next ptr
793                          */
794                         *sp->pptr =
795                             htb_id_find_next_upper(prio, sp->root, *sp->pid);
796                 }
797                 *sp->pid = 0;   /* ptr is valid now so that remove this hint as it
798                                  * can become out of date quickly
799                                  */
800                 if (!*sp->pptr) {       /* we are at right end; rewind & go up */
801                         *sp->pptr = sp->root;
802                         while ((*sp->pptr)->rb_left)
803                                 *sp->pptr = (*sp->pptr)->rb_left;
804                         if (sp > stk) {
805                                 sp--;
806                                 if (!*sp->pptr) {
807                                         WARN_ON(1);
808                                         return NULL;
809                                 }
810                                 htb_next_rb_node(sp->pptr);
811                         }
812                 } else {
813                         struct htb_class *cl;
814                         struct htb_prio *clp;
815 
816                         cl = rb_entry(*sp->pptr, struct htb_class, node[prio]);
817                         if (!cl->level)
818                                 return cl;
819                         clp = &cl->un.inner.clprio[prio];
820                         (++sp)->root = clp->feed.rb_node;
821                         sp->pptr = &clp->ptr;
822                         sp->pid = &clp->last_ptr_id;
823                 }
824         }
825         WARN_ON(1);
826         return NULL;
827 }
828 
829 /* dequeues packet at given priority and level; call only if
830  * you are sure that there is active class at prio/level
831  */
832 static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, const int prio,
833                                         const int level)
834 {
835         struct sk_buff *skb = NULL;
836         struct htb_class *cl, *start;
837         struct htb_level *hlevel = &q->hlevel[level];
838         struct htb_prio *hprio = &hlevel->hprio[prio];
839 
840         /* look initial class up in the row */
841         start = cl = htb_lookup_leaf(hprio, prio);
842 
843         do {
844 next:
845                 if (unlikely(!cl))
846                         return NULL;
847 
848                 /* class can be empty - it is unlikely but can be true if leaf
849                  * qdisc drops packets in enqueue routine or if someone used
850                  * graft operation on the leaf since last dequeue;
851                  * simply deactivate and skip such class
852                  */
853                 if (unlikely(cl->un.leaf.q->q.qlen == 0)) {
854                         struct htb_class *next;
855                         htb_deactivate(q, cl);
856 
857                         /* row/level might become empty */
858                         if ((q->row_mask[level] & (1 << prio)) == 0)
859                                 return NULL;
860 
861                         next = htb_lookup_leaf(hprio, prio);
862 
863                         if (cl == start)        /* fix start if we just deleted it */
864                                 start = next;
865                         cl = next;
866                         goto next;
867                 }
868 
869                 skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
870                 if (likely(skb != NULL))
871                         break;
872 
873                 qdisc_warn_nonwc("htb", cl->un.leaf.q);
874                 htb_next_rb_node(level ? &cl->parent->un.inner.clprio[prio].ptr:
875                                          &q->hlevel[0].hprio[prio].ptr);
876                 cl = htb_lookup_leaf(hprio, prio);
877 
878         } while (cl != start);
879 
880         if (likely(skb != NULL)) {
881                 bstats_update(&cl->bstats, skb);
882                 cl->un.leaf.deficit[level] -= qdisc_pkt_len(skb);
883                 if (cl->un.leaf.deficit[level] < 0) {
884                         cl->un.leaf.deficit[level] += cl->quantum;
885                         htb_next_rb_node(level ? &cl->parent->un.inner.clprio[prio].ptr :
886                                                  &q->hlevel[0].hprio[prio].ptr);
887                 }
888                 /* this used to be after charge_class but this constelation
889                  * gives us slightly better performance
890                  */
891                 if (!cl->un.leaf.q->q.qlen)
892                         htb_deactivate(q, cl);
893                 htb_charge_class(q, cl, level, skb);
894         }
895         return skb;
896 }
897 
898 static struct sk_buff *htb_dequeue(struct Qdisc *sch)
899 {
900         struct sk_buff *skb;
901         struct htb_sched *q = qdisc_priv(sch);
902         int level;
903         s64 next_event;
904         unsigned long start_at;
905 
906         /* try to dequeue direct packets as high prio (!) to minimize cpu work */
907         skb = __qdisc_dequeue_head(&q->direct_queue);
908         if (skb != NULL) {
909 ok:
910                 qdisc_bstats_update(sch, skb);
911                 qdisc_qstats_backlog_dec(sch, skb);
912                 sch->q.qlen--;
913                 return skb;
914         }
915 
916         if (!sch->q.qlen)
917                 goto fin;
918         q->now = ktime_get_ns();
919         start_at = jiffies;
920 
921         next_event = q->now + 5LLU * NSEC_PER_SEC;
922 
923         for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
924                 /* common case optimization - skip event handler quickly */
925                 int m;
926                 s64 event = q->near_ev_cache[level];
927 
928                 if (q->now >= event) {
929                         event = htb_do_events(q, level, start_at);
930                         if (!event)
931                                 event = q->now + NSEC_PER_SEC;
932                         q->near_ev_cache[level] = event;
933                 }
934 
935                 if (next_event > event)
936                         next_event = event;
937 
938                 m = ~q->row_mask[level];
939                 while (m != (int)(-1)) {
940                         int prio = ffz(m);
941 
942                         m |= 1 << prio;
943                         skb = htb_dequeue_tree(q, prio, level);
944                         if (likely(skb != NULL))
945                                 goto ok;
946                 }
947         }
948         qdisc_qstats_overlimit(sch);
949         if (likely(next_event > q->now))
950                 qdisc_watchdog_schedule_ns(&q->watchdog, next_event);
951         else
952                 schedule_work(&q->work);
953 fin:
954         return skb;
955 }
956 
957 /* reset all classes */
958 /* always caled under BH & queue lock */
959 static void htb_reset(struct Qdisc *sch)
960 {
961         struct htb_sched *q = qdisc_priv(sch);
962         struct htb_class *cl;
963         unsigned int i;
964 
965         for (i = 0; i < q->clhash.hashsize; i++) {
966                 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
967                         if (cl->level)
968                                 memset(&cl->un.inner, 0, sizeof(cl->un.inner));
969                         else {
970                                 if (cl->un.leaf.q)
971                                         qdisc_reset(cl->un.leaf.q);
972                                 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
973                         }
974                         cl->prio_activity = 0;
975                         cl->cmode = HTB_CAN_SEND;
976                 }
977         }
978         qdisc_watchdog_cancel(&q->watchdog);
979         __qdisc_reset_queue(&q->direct_queue);
980         sch->q.qlen = 0;
981         sch->qstats.backlog = 0;
982         memset(q->hlevel, 0, sizeof(q->hlevel));
983         memset(q->row_mask, 0, sizeof(q->row_mask));
984         for (i = 0; i < TC_HTB_NUMPRIO; i++)
985                 INIT_LIST_HEAD(q->drops + i);
986 }
987 
988 static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = {
989         [TCA_HTB_PARMS] = { .len = sizeof(struct tc_htb_opt) },
990         [TCA_HTB_INIT]  = { .len = sizeof(struct tc_htb_glob) },
991         [TCA_HTB_CTAB]  = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
992         [TCA_HTB_RTAB]  = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
993         [TCA_HTB_DIRECT_QLEN] = { .type = NLA_U32 },
994         [TCA_HTB_RATE64] = { .type = NLA_U64 },
995         [TCA_HTB_CEIL64] = { .type = NLA_U64 },
996 };
997 
998 static void htb_work_func(struct work_struct *work)
999 {
1000         struct htb_sched *q = container_of(work, struct htb_sched, work);
1001         struct Qdisc *sch = q->watchdog.qdisc;
1002 
1003         rcu_read_lock();
1004         __netif_schedule(qdisc_root(sch));
1005         rcu_read_unlock();
1006 }
1007 
1008 static int htb_init(struct Qdisc *sch, struct nlattr *opt)
1009 {
1010         struct htb_sched *q = qdisc_priv(sch);
1011         struct nlattr *tb[TCA_HTB_MAX + 1];
1012         struct tc_htb_glob *gopt;
1013         int err;
1014         int i;
1015 
1016         if (!opt)
1017                 return -EINVAL;
1018 
1019         err = nla_parse_nested(tb, TCA_HTB_MAX, opt, htb_policy);
1020         if (err < 0)
1021                 return err;
1022 
1023         if (!tb[TCA_HTB_INIT])
1024                 return -EINVAL;
1025 
1026         gopt = nla_data(tb[TCA_HTB_INIT]);
1027         if (gopt->version != HTB_VER >> 16)
1028                 return -EINVAL;
1029 
1030         err = qdisc_class_hash_init(&q->clhash);
1031         if (err < 0)
1032                 return err;
1033         for (i = 0; i < TC_HTB_NUMPRIO; i++)
1034                 INIT_LIST_HEAD(q->drops + i);
1035 
1036         qdisc_watchdog_init(&q->watchdog, sch);
1037         INIT_WORK(&q->work, htb_work_func);
1038         qdisc_skb_head_init(&q->direct_queue);
1039 
1040         if (tb[TCA_HTB_DIRECT_QLEN])
1041                 q->direct_qlen = nla_get_u32(tb[TCA_HTB_DIRECT_QLEN]);
1042         else
1043                 q->direct_qlen = qdisc_dev(sch)->tx_queue_len;
1044 
1045         if ((q->rate2quantum = gopt->rate2quantum) < 1)
1046                 q->rate2quantum = 1;
1047         q->defcls = gopt->defcls;
1048 
1049         return 0;
1050 }
1051 
1052 static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1053 {
1054         struct htb_sched *q = qdisc_priv(sch);
1055         struct nlattr *nest;
1056         struct tc_htb_glob gopt;
1057 
1058         /* Its safe to not acquire qdisc lock. As we hold RTNL,
1059          * no change can happen on the qdisc parameters.
1060          */
1061 
1062         gopt.direct_pkts = q->direct_pkts;
1063         gopt.version = HTB_VER;
1064         gopt.rate2quantum = q->rate2quantum;
1065         gopt.defcls = q->defcls;
1066         gopt.debug = 0;
1067 
1068         nest = nla_nest_start(skb, TCA_OPTIONS);
1069         if (nest == NULL)
1070                 goto nla_put_failure;
1071         if (nla_put(skb, TCA_HTB_INIT, sizeof(gopt), &gopt) ||
1072             nla_put_u32(skb, TCA_HTB_DIRECT_QLEN, q->direct_qlen))
1073                 goto nla_put_failure;
1074 
1075         return nla_nest_end(skb, nest);
1076 
1077 nla_put_failure:
1078         nla_nest_cancel(skb, nest);
1079         return -1;
1080 }
1081 
1082 static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1083                           struct sk_buff *skb, struct tcmsg *tcm)
1084 {
1085         struct htb_class *cl = (struct htb_class *)arg;
1086         struct nlattr *nest;
1087         struct tc_htb_opt opt;
1088 
1089         /* Its safe to not acquire qdisc lock. As we hold RTNL,
1090          * no change can happen on the class parameters.
1091          */
1092         tcm->tcm_parent = cl->parent ? cl->parent->common.classid : TC_H_ROOT;
1093         tcm->tcm_handle = cl->common.classid;
1094         if (!cl->level && cl->un.leaf.q)
1095                 tcm->tcm_info = cl->un.leaf.q->handle;
1096 
1097         nest = nla_nest_start(skb, TCA_OPTIONS);
1098         if (nest == NULL)
1099                 goto nla_put_failure;
1100 
1101         memset(&opt, 0, sizeof(opt));
1102 
1103         psched_ratecfg_getrate(&opt.rate, &cl->rate);
1104         opt.buffer = PSCHED_NS2TICKS(cl->buffer);
1105         psched_ratecfg_getrate(&opt.ceil, &cl->ceil);
1106         opt.cbuffer = PSCHED_NS2TICKS(cl->cbuffer);
1107         opt.quantum = cl->quantum;
1108         opt.prio = cl->prio;
1109         opt.level = cl->level;
1110         if (nla_put(skb, TCA_HTB_PARMS, sizeof(opt), &opt))
1111                 goto nla_put_failure;
1112         if ((cl->rate.rate_bytes_ps >= (1ULL << 32)) &&
1113             nla_put_u64_64bit(skb, TCA_HTB_RATE64, cl->rate.rate_bytes_ps,
1114                               TCA_HTB_PAD))
1115                 goto nla_put_failure;
1116         if ((cl->ceil.rate_bytes_ps >= (1ULL << 32)) &&
1117             nla_put_u64_64bit(skb, TCA_HTB_CEIL64, cl->ceil.rate_bytes_ps,
1118                               TCA_HTB_PAD))
1119                 goto nla_put_failure;
1120 
1121         return nla_nest_end(skb, nest);
1122 
1123 nla_put_failure:
1124         nla_nest_cancel(skb, nest);
1125         return -1;
1126 }
1127 
1128 static int
1129 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
1130 {
1131         struct htb_class *cl = (struct htb_class *)arg;
1132         struct gnet_stats_queue qs = {
1133                 .drops = cl->drops,
1134         };
1135         __u32 qlen = 0;
1136 
1137         if (!cl->level && cl->un.leaf.q) {
1138                 qlen = cl->un.leaf.q->q.qlen;
1139                 qs.backlog = cl->un.leaf.q->qstats.backlog;
1140         }
1141         cl->xstats.tokens = clamp_t(s64, PSCHED_NS2TICKS(cl->tokens),
1142                                     INT_MIN, INT_MAX);
1143         cl->xstats.ctokens = clamp_t(s64, PSCHED_NS2TICKS(cl->ctokens),
1144                                      INT_MIN, INT_MAX);
1145 
1146         if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
1147                                   d, NULL, &cl->bstats) < 0 ||
1148             gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1149             gnet_stats_copy_queue(d, NULL, &qs, qlen) < 0)
1150                 return -1;
1151 
1152         return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1153 }
1154 
1155 static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1156                      struct Qdisc **old)
1157 {
1158         struct htb_class *cl = (struct htb_class *)arg;
1159 
1160         if (cl->level)
1161                 return -EINVAL;
1162         if (new == NULL &&
1163             (new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1164                                      cl->common.classid)) == NULL)
1165                 return -ENOBUFS;
1166 
1167         *old = qdisc_replace(sch, new, &cl->un.leaf.q);
1168         return 0;
1169 }
1170 
1171 static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg)
1172 {
1173         struct htb_class *cl = (struct htb_class *)arg;
1174         return !cl->level ? cl->un.leaf.q : NULL;
1175 }
1176 
1177 static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
1178 {
1179         struct htb_class *cl = (struct htb_class *)arg;
1180 
1181         if (cl->un.leaf.q->q.qlen == 0)
1182                 htb_deactivate(qdisc_priv(sch), cl);
1183 }
1184 
1185 static unsigned long htb_get(struct Qdisc *sch, u32 classid)
1186 {
1187         struct htb_class *cl = htb_find(classid, sch);
1188         if (cl)
1189                 cl->refcnt++;
1190         return (unsigned long)cl;
1191 }
1192 
1193 static inline int htb_parent_last_child(struct htb_class *cl)
1194 {
1195         if (!cl->parent)
1196                 /* the root class */
1197                 return 0;
1198         if (cl->parent->children > 1)
1199                 /* not the last child */
1200                 return 0;
1201         return 1;
1202 }
1203 
1204 static void htb_parent_to_leaf(struct htb_sched *q, struct htb_class *cl,
1205                                struct Qdisc *new_q)
1206 {
1207         struct htb_class *parent = cl->parent;
1208 
1209         WARN_ON(cl->level || !cl->un.leaf.q || cl->prio_activity);
1210 
1211         if (parent->cmode != HTB_CAN_SEND)
1212                 htb_safe_rb_erase(&parent->pq_node,
1213                                   &q->hlevel[parent->level].wait_pq);
1214 
1215         parent->level = 0;
1216         memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1217         INIT_LIST_HEAD(&parent->un.leaf.drop_list);
1218         parent->un.leaf.q = new_q ? new_q : &noop_qdisc;
1219         parent->tokens = parent->buffer;
1220         parent->ctokens = parent->cbuffer;
1221         parent->t_c = ktime_get_ns();
1222         parent->cmode = HTB_CAN_SEND;
1223 }
1224 
1225 static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
1226 {
1227         if (!cl->level) {
1228                 WARN_ON(!cl->un.leaf.q);
1229                 qdisc_destroy(cl->un.leaf.q);
1230         }
1231         gen_kill_estimator(&cl->rate_est);
1232         tcf_destroy_chain(&cl->filter_list);
1233         kfree(cl);
1234 }
1235 
1236 static void htb_destroy(struct Qdisc *sch)
1237 {
1238         struct htb_sched *q = qdisc_priv(sch);
1239         struct hlist_node *next;
1240         struct htb_class *cl;
1241         unsigned int i;
1242 
1243         cancel_work_sync(&q->work);
1244         qdisc_watchdog_cancel(&q->watchdog);
1245         /* This line used to be after htb_destroy_class call below
1246          * and surprisingly it worked in 2.4. But it must precede it
1247          * because filter need its target class alive to be able to call
1248          * unbind_filter on it (without Oops).
1249          */
1250         tcf_destroy_chain(&q->filter_list);
1251 
1252         for (i = 0; i < q->clhash.hashsize; i++) {
1253                 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode)
1254                         tcf_destroy_chain(&cl->filter_list);
1255         }
1256         for (i = 0; i < q->clhash.hashsize; i++) {
1257                 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
1258                                           common.hnode)
1259                         htb_destroy_class(sch, cl);
1260         }
1261         qdisc_class_hash_destroy(&q->clhash);
1262         __qdisc_reset_queue(&q->direct_queue);
1263 }
1264 
1265 static int htb_delete(struct Qdisc *sch, unsigned long arg)
1266 {
1267         struct htb_sched *q = qdisc_priv(sch);
1268         struct htb_class *cl = (struct htb_class *)arg;
1269         struct Qdisc *new_q = NULL;
1270         int last_child = 0;
1271 
1272         /* TODO: why don't allow to delete subtree ? references ? does
1273          * tc subsys guarantee us that in htb_destroy it holds no class
1274          * refs so that we can remove children safely there ?
1275          */
1276         if (cl->children || cl->filter_cnt)
1277                 return -EBUSY;
1278 
1279         if (!cl->level && htb_parent_last_child(cl)) {
1280                 new_q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
1281                                           cl->parent->common.classid);
1282                 last_child = 1;
1283         }
1284 
1285         sch_tree_lock(sch);
1286 
1287         if (!cl->level) {
1288                 unsigned int qlen = cl->un.leaf.q->q.qlen;
1289                 unsigned int backlog = cl->un.leaf.q->qstats.backlog;
1290 
1291                 qdisc_reset(cl->un.leaf.q);
1292                 qdisc_tree_reduce_backlog(cl->un.leaf.q, qlen, backlog);
1293         }
1294 
1295         /* delete from hash and active; remainder in destroy_class */
1296         qdisc_class_hash_remove(&q->clhash, &cl->common);
1297         if (cl->parent)
1298                 cl->parent->children--;
1299 
1300         if (cl->prio_activity)
1301                 htb_deactivate(q, cl);
1302 
1303         if (cl->cmode != HTB_CAN_SEND)
1304                 htb_safe_rb_erase(&cl->pq_node,
1305                                   &q->hlevel[cl->level].wait_pq);
1306 
1307         if (last_child)
1308                 htb_parent_to_leaf(q, cl, new_q);
1309 
1310         BUG_ON(--cl->refcnt == 0);
1311         /*
1312          * This shouldn't happen: we "hold" one cops->get() when called
1313          * from tc_ctl_tclass; the destroy method is done from cops->put().
1314          */
1315 
1316         sch_tree_unlock(sch);
1317         return 0;
1318 }
1319 
1320 static void htb_put(struct Qdisc *sch, unsigned long arg)
1321 {
1322         struct htb_class *cl = (struct htb_class *)arg;
1323 
1324         if (--cl->refcnt == 0)
1325                 htb_destroy_class(sch, cl);
1326 }
1327 
1328 static int htb_change_class(struct Qdisc *sch, u32 classid,
1329                             u32 parentid, struct nlattr **tca,
1330                             unsigned long *arg)
1331 {
1332         int err = -EINVAL;
1333         struct htb_sched *q = qdisc_priv(sch);
1334         struct htb_class *cl = (struct htb_class *)*arg, *parent;
1335         struct nlattr *opt = tca[TCA_OPTIONS];
1336         struct nlattr *tb[TCA_HTB_MAX + 1];
1337         struct tc_htb_opt *hopt;
1338         u64 rate64, ceil64;
1339 
1340         /* extract all subattrs from opt attr */
1341         if (!opt)
1342                 goto failure;
1343 
1344         err = nla_parse_nested(tb, TCA_HTB_MAX, opt, htb_policy);
1345         if (err < 0)
1346                 goto failure;
1347 
1348         err = -EINVAL;
1349         if (tb[TCA_HTB_PARMS] == NULL)
1350                 goto failure;
1351 
1352         parent = parentid == TC_H_ROOT ? NULL : htb_find(parentid, sch);
1353 
1354         hopt = nla_data(tb[TCA_HTB_PARMS]);
1355         if (!hopt->rate.rate || !hopt->ceil.rate)
1356                 goto failure;
1357 
1358         /* Keeping backward compatible with rate_table based iproute2 tc */
1359         if (hopt->rate.linklayer == TC_LINKLAYER_UNAWARE)
1360                 qdisc_put_rtab(qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB]));
1361 
1362         if (hopt->ceil.linklayer == TC_LINKLAYER_UNAWARE)
1363                 qdisc_put_rtab(qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB]));
1364 
1365         if (!cl) {              /* new class */
1366                 struct Qdisc *new_q;
1367                 int prio;
1368                 struct {
1369                         struct nlattr           nla;
1370                         struct gnet_estimator   opt;
1371                 } est = {
1372                         .nla = {
1373                                 .nla_len        = nla_attr_size(sizeof(est.opt)),
1374                                 .nla_type       = TCA_RATE,
1375                         },
1376                         .opt = {
1377                                 /* 4s interval, 16s averaging constant */
1378                                 .interval       = 2,
1379                                 .ewma_log       = 2,
1380                         },
1381                 };
1382 
1383                 /* check for valid classid */
1384                 if (!classid || TC_H_MAJ(classid ^ sch->handle) ||
1385                     htb_find(classid, sch))
1386                         goto failure;
1387 
1388                 /* check maximal depth */
1389                 if (parent && parent->parent && parent->parent->level < 2) {
1390                         pr_err("htb: tree is too deep\n");
1391                         goto failure;
1392                 }
1393                 err = -ENOBUFS;
1394                 cl = kzalloc(sizeof(*cl), GFP_KERNEL);
1395                 if (!cl)
1396                         goto failure;
1397 
1398                 if (htb_rate_est || tca[TCA_RATE]) {
1399                         err = gen_new_estimator(&cl->bstats, NULL,
1400                                                 &cl->rate_est,
1401                                                 NULL,
1402                                                 qdisc_root_sleeping_running(sch),
1403                                                 tca[TCA_RATE] ? : &est.nla);
1404                         if (err) {
1405                                 kfree(cl);
1406                                 goto failure;
1407                         }
1408                 }
1409 
1410                 cl->refcnt = 1;
1411                 cl->children = 0;
1412                 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1413                 RB_CLEAR_NODE(&cl->pq_node);
1414 
1415                 for (prio = 0; prio < TC_HTB_NUMPRIO; prio++)
1416                         RB_CLEAR_NODE(&cl->node[prio]);
1417 
1418                 /* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1419                  * so that can't be used inside of sch_tree_lock
1420                  * -- thanks to Karlis Peisenieks
1421                  */
1422                 new_q = qdisc_create_dflt(sch->dev_queue,
1423                                           &pfifo_qdisc_ops, classid);
1424                 sch_tree_lock(sch);
1425                 if (parent && !parent->level) {
1426                         unsigned int qlen = parent->un.leaf.q->q.qlen;
1427                         unsigned int backlog = parent->un.leaf.q->qstats.backlog;
1428 
1429                         /* turn parent into inner node */
1430                         qdisc_reset(parent->un.leaf.q);
1431                         qdisc_tree_reduce_backlog(parent->un.leaf.q, qlen, backlog);
1432                         qdisc_destroy(parent->un.leaf.q);
1433                         if (parent->prio_activity)
1434                                 htb_deactivate(q, parent);
1435 
1436                         /* remove from evt list because of level change */
1437                         if (parent->cmode != HTB_CAN_SEND) {
1438                                 htb_safe_rb_erase(&parent->pq_node, &q->hlevel[0].wait_pq);
1439                                 parent->cmode = HTB_CAN_SEND;
1440                         }
1441                         parent->level = (parent->parent ? parent->parent->level
1442                                          : TC_HTB_MAXDEPTH) - 1;
1443                         memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1444                 }
1445                 /* leaf (we) needs elementary qdisc */
1446                 cl->un.leaf.q = new_q ? new_q : &noop_qdisc;
1447 
1448                 cl->common.classid = classid;
1449                 cl->parent = parent;
1450 
1451                 /* set class to be in HTB_CAN_SEND state */
1452                 cl->tokens = PSCHED_TICKS2NS(hopt->buffer);
1453                 cl->ctokens = PSCHED_TICKS2NS(hopt->cbuffer);
1454                 cl->mbuffer = 60ULL * NSEC_PER_SEC;     /* 1min */
1455                 cl->t_c = ktime_get_ns();
1456                 cl->cmode = HTB_CAN_SEND;
1457 
1458                 /* attach to the hash list and parent's family */
1459                 qdisc_class_hash_insert(&q->clhash, &cl->common);
1460                 if (parent)
1461                         parent->children++;
1462         } else {
1463                 if (tca[TCA_RATE]) {
1464                         err = gen_replace_estimator(&cl->bstats, NULL,
1465                                                     &cl->rate_est,
1466                                                     NULL,
1467                                                     qdisc_root_sleeping_running(sch),
1468                                                     tca[TCA_RATE]);
1469                         if (err)
1470                                 return err;
1471                 }
1472                 sch_tree_lock(sch);
1473         }
1474 
1475         rate64 = tb[TCA_HTB_RATE64] ? nla_get_u64(tb[TCA_HTB_RATE64]) : 0;
1476 
1477         ceil64 = tb[TCA_HTB_CEIL64] ? nla_get_u64(tb[TCA_HTB_CEIL64]) : 0;
1478 
1479         psched_ratecfg_precompute(&cl->rate, &hopt->rate, rate64);
1480         psched_ratecfg_precompute(&cl->ceil, &hopt->ceil, ceil64);
1481 
1482         /* it used to be a nasty bug here, we have to check that node
1483          * is really leaf before changing cl->un.leaf !
1484          */
1485         if (!cl->level) {
1486                 u64 quantum = cl->rate.rate_bytes_ps;
1487 
1488                 do_div(quantum, q->rate2quantum);
1489                 cl->quantum = min_t(u64, quantum, INT_MAX);
1490 
1491                 if (!hopt->quantum && cl->quantum < 1000) {
1492                         pr_warn("HTB: quantum of class %X is small. Consider r2q change.\n",
1493                                 cl->common.classid);
1494                         cl->quantum = 1000;
1495                 }
1496                 if (!hopt->quantum && cl->quantum > 200000) {
1497                         pr_warn("HTB: quantum of class %X is big. Consider r2q change.\n",
1498                                 cl->common.classid);
1499                         cl->quantum = 200000;
1500                 }
1501                 if (hopt->quantum)
1502                         cl->quantum = hopt->quantum;
1503                 if ((cl->prio = hopt->prio) >= TC_HTB_NUMPRIO)
1504                         cl->prio = TC_HTB_NUMPRIO - 1;
1505         }
1506 
1507         cl->buffer = PSCHED_TICKS2NS(hopt->buffer);
1508         cl->cbuffer = PSCHED_TICKS2NS(hopt->cbuffer);
1509 
1510         sch_tree_unlock(sch);
1511 
1512         qdisc_class_hash_grow(sch, &q->clhash);
1513 
1514         *arg = (unsigned long)cl;
1515         return 0;
1516 
1517 failure:
1518         return err;
1519 }
1520 
1521 static struct tcf_proto __rcu **htb_find_tcf(struct Qdisc *sch,
1522                                              unsigned long arg)
1523 {
1524         struct htb_sched *q = qdisc_priv(sch);
1525         struct htb_class *cl = (struct htb_class *)arg;
1526         struct tcf_proto __rcu **fl = cl ? &cl->filter_list : &q->filter_list;
1527 
1528         return fl;
1529 }
1530 
1531 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1532                                      u32 classid)
1533 {
1534         struct htb_class *cl = htb_find(classid, sch);
1535 
1536         /*if (cl && !cl->level) return 0;
1537          * The line above used to be there to prevent attaching filters to
1538          * leaves. But at least tc_index filter uses this just to get class
1539          * for other reasons so that we have to allow for it.
1540          * ----
1541          * 19.6.2002 As Werner explained it is ok - bind filter is just
1542          * another way to "lock" the class - unlike "get" this lock can
1543          * be broken by class during destroy IIUC.
1544          */
1545         if (cl)
1546                 cl->filter_cnt++;
1547         return (unsigned long)cl;
1548 }
1549 
1550 static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1551 {
1552         struct htb_class *cl = (struct htb_class *)arg;
1553 
1554         if (cl)
1555                 cl->filter_cnt--;
1556 }
1557 
1558 static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1559 {
1560         struct htb_sched *q = qdisc_priv(sch);
1561         struct htb_class *cl;
1562         unsigned int i;
1563 
1564         if (arg->stop)
1565                 return;
1566 
1567         for (i = 0; i < q->clhash.hashsize; i++) {
1568                 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
1569                         if (arg->count < arg->skip) {
1570                                 arg->count++;
1571                                 continue;
1572                         }
1573                         if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1574                                 arg->stop = 1;
1575                                 return;
1576                         }
1577                         arg->count++;
1578                 }
1579         }
1580 }
1581 
1582 static const struct Qdisc_class_ops htb_class_ops = {
1583         .graft          =       htb_graft,
1584         .leaf           =       htb_leaf,
1585         .qlen_notify    =       htb_qlen_notify,
1586         .get            =       htb_get,
1587         .put            =       htb_put,
1588         .change         =       htb_change_class,
1589         .delete         =       htb_delete,
1590         .walk           =       htb_walk,
1591         .tcf_chain      =       htb_find_tcf,
1592         .bind_tcf       =       htb_bind_filter,
1593         .unbind_tcf     =       htb_unbind_filter,
1594         .dump           =       htb_dump_class,
1595         .dump_stats     =       htb_dump_class_stats,
1596 };
1597 
1598 static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
1599         .cl_ops         =       &htb_class_ops,
1600         .id             =       "htb",
1601         .priv_size      =       sizeof(struct htb_sched),
1602         .enqueue        =       htb_enqueue,
1603         .dequeue        =       htb_dequeue,
1604         .peek           =       qdisc_peek_dequeued,
1605         .init           =       htb_init,
1606         .reset          =       htb_reset,
1607         .destroy        =       htb_destroy,
1608         .dump           =       htb_dump,
1609         .owner          =       THIS_MODULE,
1610 };
1611 
1612 static int __init htb_module_init(void)
1613 {
1614         return register_qdisc(&htb_qdisc_ops);
1615 }
1616 static void __exit htb_module_exit(void)
1617 {
1618         unregister_qdisc(&htb_qdisc_ops);
1619 }
1620 
1621 module_init(htb_module_init)
1622 module_exit(htb_module_exit)
1623 MODULE_LICENSE("GPL");
1624 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us