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[mirror_ubuntu-zesty-kernel.git] / net / sched / sch_sfq.c
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1/*
2 * net/sched/sch_sfq.c Stochastic Fairness Queueing discipline.
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: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12#include <linux/module.h>
13#include <linux/types.h>
14#include <linux/kernel.h>
15#include <linux/jiffies.h>
16#include <linux/string.h>
17#include <linux/in.h>
18#include <linux/errno.h>
19#include <linux/init.h>
20#include <linux/skbuff.h>
21#include <linux/jhash.h>
22#include <linux/slab.h>
23#include <linux/vmalloc.h>
24#include <net/netlink.h>
25#include <net/pkt_sched.h>
26#include <net/red.h>
27
28
29/* Stochastic Fairness Queuing algorithm.
30 =======================================
31
32 Source:
33 Paul E. McKenney "Stochastic Fairness Queuing",
34 IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
35
36 Paul E. McKenney "Stochastic Fairness Queuing",
37 "Interworking: Research and Experience", v.2, 1991, p.113-131.
38
39
40 See also:
41 M. Shreedhar and George Varghese "Efficient Fair
42 Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
43
44
45 This is not the thing that is usually called (W)FQ nowadays.
46 It does not use any timestamp mechanism, but instead
47 processes queues in round-robin order.
48
49 ADVANTAGE:
50
51 - It is very cheap. Both CPU and memory requirements are minimal.
52
53 DRAWBACKS:
54
55 - "Stochastic" -> It is not 100% fair.
56 When hash collisions occur, several flows are considered as one.
57
58 - "Round-robin" -> It introduces larger delays than virtual clock
59 based schemes, and should not be used for isolating interactive
60 traffic from non-interactive. It means, that this scheduler
61 should be used as leaf of CBQ or P3, which put interactive traffic
62 to higher priority band.
63
64 We still need true WFQ for top level CSZ, but using WFQ
65 for the best effort traffic is absolutely pointless:
66 SFQ is superior for this purpose.
67
68 IMPLEMENTATION:
69 This implementation limits :
70 - maximal queue length per flow to 127 packets.
71 - max mtu to 2^18-1;
72 - max 65408 flows,
73 - number of hash buckets to 65536.
74
75 It is easy to increase these values, but not in flight. */
76
77#define SFQ_MAX_DEPTH 127 /* max number of packets per flow */
78#define SFQ_DEFAULT_FLOWS 128
79#define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
80#define SFQ_EMPTY_SLOT 0xffff
81#define SFQ_DEFAULT_HASH_DIVISOR 1024
82
83/* We use 16 bits to store allot, and want to handle packets up to 64K
84 * Scale allot by 8 (1<<3) so that no overflow occurs.
85 */
86#define SFQ_ALLOT_SHIFT 3
87#define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
88
89/* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
90typedef u16 sfq_index;
91
92/*
93 * We dont use pointers to save space.
94 * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
95 * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
96 * are 'pointers' to dep[] array
97 */
98struct sfq_head {
99 sfq_index next;
100 sfq_index prev;
101};
102
103struct sfq_slot {
104 struct sk_buff *skblist_next;
105 struct sk_buff *skblist_prev;
106 sfq_index qlen; /* number of skbs in skblist */
107 sfq_index next; /* next slot in sfq RR chain */
108 struct sfq_head dep; /* anchor in dep[] chains */
109 unsigned short hash; /* hash value (index in ht[]) */
110 short allot; /* credit for this slot */
111
112 unsigned int backlog;
113 struct red_vars vars;
114};
115
116struct sfq_sched_data {
117/* frequently used fields */
118 int limit; /* limit of total number of packets in this qdisc */
119 unsigned int divisor; /* number of slots in hash table */
120 u8 headdrop;
121 u8 maxdepth; /* limit of packets per flow */
122
123 u32 perturbation;
124 u8 cur_depth; /* depth of longest slot */
125 u8 flags;
126 unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
127 struct tcf_proto __rcu *filter_list;
128 sfq_index *ht; /* Hash table ('divisor' slots) */
129 struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
130
131 struct red_parms *red_parms;
132 struct tc_sfqred_stats stats;
133 struct sfq_slot *tail; /* current slot in round */
134
135 struct sfq_head dep[SFQ_MAX_DEPTH + 1];
136 /* Linked lists of slots, indexed by depth
137 * dep[0] : list of unused flows
138 * dep[1] : list of flows with 1 packet
139 * dep[X] : list of flows with X packets
140 */
141
142 unsigned int maxflows; /* number of flows in flows array */
143 int perturb_period;
144 unsigned int quantum; /* Allotment per round: MUST BE >= MTU */
145 struct timer_list perturb_timer;
146};
147
148/*
149 * sfq_head are either in a sfq_slot or in dep[] array
150 */
151static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
152{
153 if (val < SFQ_MAX_FLOWS)
154 return &q->slots[val].dep;
155 return &q->dep[val - SFQ_MAX_FLOWS];
156}
157
158static unsigned int sfq_hash(const struct sfq_sched_data *q,
159 const struct sk_buff *skb)
160{
161 return skb_get_hash_perturb(skb, q->perturbation) & (q->divisor - 1);
162}
163
164static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
165 int *qerr)
166{
167 struct sfq_sched_data *q = qdisc_priv(sch);
168 struct tcf_result res;
169 struct tcf_proto *fl;
170 int result;
171
172 if (TC_H_MAJ(skb->priority) == sch->handle &&
173 TC_H_MIN(skb->priority) > 0 &&
174 TC_H_MIN(skb->priority) <= q->divisor)
175 return TC_H_MIN(skb->priority);
176
177 fl = rcu_dereference_bh(q->filter_list);
178 if (!fl)
179 return sfq_hash(q, skb) + 1;
180
181 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
182 result = tc_classify(skb, fl, &res, false);
183 if (result >= 0) {
184#ifdef CONFIG_NET_CLS_ACT
185 switch (result) {
186 case TC_ACT_STOLEN:
187 case TC_ACT_QUEUED:
188 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
189 case TC_ACT_SHOT:
190 return 0;
191 }
192#endif
193 if (TC_H_MIN(res.classid) <= q->divisor)
194 return TC_H_MIN(res.classid);
195 }
196 return 0;
197}
198
199/*
200 * x : slot number [0 .. SFQ_MAX_FLOWS - 1]
201 */
202static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
203{
204 sfq_index p, n;
205 struct sfq_slot *slot = &q->slots[x];
206 int qlen = slot->qlen;
207
208 p = qlen + SFQ_MAX_FLOWS;
209 n = q->dep[qlen].next;
210
211 slot->dep.next = n;
212 slot->dep.prev = p;
213
214 q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */
215 sfq_dep_head(q, n)->prev = x;
216}
217
218#define sfq_unlink(q, x, n, p) \
219 do { \
220 n = q->slots[x].dep.next; \
221 p = q->slots[x].dep.prev; \
222 sfq_dep_head(q, p)->next = n; \
223 sfq_dep_head(q, n)->prev = p; \
224 } while (0)
225
226
227static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
228{
229 sfq_index p, n;
230 int d;
231
232 sfq_unlink(q, x, n, p);
233
234 d = q->slots[x].qlen--;
235 if (n == p && q->cur_depth == d)
236 q->cur_depth--;
237 sfq_link(q, x);
238}
239
240static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
241{
242 sfq_index p, n;
243 int d;
244
245 sfq_unlink(q, x, n, p);
246
247 d = ++q->slots[x].qlen;
248 if (q->cur_depth < d)
249 q->cur_depth = d;
250 sfq_link(q, x);
251}
252
253/* helper functions : might be changed when/if skb use a standard list_head */
254
255/* remove one skb from tail of slot queue */
256static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
257{
258 struct sk_buff *skb = slot->skblist_prev;
259
260 slot->skblist_prev = skb->prev;
261 skb->prev->next = (struct sk_buff *)slot;
262 skb->next = skb->prev = NULL;
263 return skb;
264}
265
266/* remove one skb from head of slot queue */
267static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
268{
269 struct sk_buff *skb = slot->skblist_next;
270
271 slot->skblist_next = skb->next;
272 skb->next->prev = (struct sk_buff *)slot;
273 skb->next = skb->prev = NULL;
274 return skb;
275}
276
277static inline void slot_queue_init(struct sfq_slot *slot)
278{
279 memset(slot, 0, sizeof(*slot));
280 slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
281}
282
283/* add skb to slot queue (tail add) */
284static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
285{
286 skb->prev = slot->skblist_prev;
287 skb->next = (struct sk_buff *)slot;
288 slot->skblist_prev->next = skb;
289 slot->skblist_prev = skb;
290}
291
292static unsigned int sfq_drop(struct Qdisc *sch)
293{
294 struct sfq_sched_data *q = qdisc_priv(sch);
295 sfq_index x, d = q->cur_depth;
296 struct sk_buff *skb;
297 unsigned int len;
298 struct sfq_slot *slot;
299
300 /* Queue is full! Find the longest slot and drop tail packet from it */
301 if (d > 1) {
302 x = q->dep[d].next;
303 slot = &q->slots[x];
304drop:
305 skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
306 len = qdisc_pkt_len(skb);
307 slot->backlog -= len;
308 sfq_dec(q, x);
309 sch->q.qlen--;
310 qdisc_qstats_drop(sch);
311 qdisc_qstats_backlog_dec(sch, skb);
312 kfree_skb(skb);
313 return len;
314 }
315
316 if (d == 1) {
317 /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
318 x = q->tail->next;
319 slot = &q->slots[x];
320 q->tail->next = slot->next;
321 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
322 goto drop;
323 }
324
325 return 0;
326}
327
328/* Is ECN parameter configured */
329static int sfq_prob_mark(const struct sfq_sched_data *q)
330{
331 return q->flags & TC_RED_ECN;
332}
333
334/* Should packets over max threshold just be marked */
335static int sfq_hard_mark(const struct sfq_sched_data *q)
336{
337 return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
338}
339
340static int sfq_headdrop(const struct sfq_sched_data *q)
341{
342 return q->headdrop;
343}
344
345static int
346sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
347{
348 struct sfq_sched_data *q = qdisc_priv(sch);
349 unsigned int hash, dropped;
350 sfq_index x, qlen;
351 struct sfq_slot *slot;
352 int uninitialized_var(ret);
353 struct sk_buff *head;
354 int delta;
355
356 hash = sfq_classify(skb, sch, &ret);
357 if (hash == 0) {
358 if (ret & __NET_XMIT_BYPASS)
359 qdisc_qstats_drop(sch);
360 kfree_skb(skb);
361 return ret;
362 }
363 hash--;
364
365 x = q->ht[hash];
366 slot = &q->slots[x];
367 if (x == SFQ_EMPTY_SLOT) {
368 x = q->dep[0].next; /* get a free slot */
369 if (x >= SFQ_MAX_FLOWS)
370 return qdisc_drop(skb, sch, to_free);
371 q->ht[hash] = x;
372 slot = &q->slots[x];
373 slot->hash = hash;
374 slot->backlog = 0; /* should already be 0 anyway... */
375 red_set_vars(&slot->vars);
376 goto enqueue;
377 }
378 if (q->red_parms) {
379 slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
380 &slot->vars,
381 slot->backlog);
382 switch (red_action(q->red_parms,
383 &slot->vars,
384 slot->vars.qavg)) {
385 case RED_DONT_MARK:
386 break;
387
388 case RED_PROB_MARK:
389 qdisc_qstats_overlimit(sch);
390 if (sfq_prob_mark(q)) {
391 /* We know we have at least one packet in queue */
392 if (sfq_headdrop(q) &&
393 INET_ECN_set_ce(slot->skblist_next)) {
394 q->stats.prob_mark_head++;
395 break;
396 }
397 if (INET_ECN_set_ce(skb)) {
398 q->stats.prob_mark++;
399 break;
400 }
401 }
402 q->stats.prob_drop++;
403 goto congestion_drop;
404
405 case RED_HARD_MARK:
406 qdisc_qstats_overlimit(sch);
407 if (sfq_hard_mark(q)) {
408 /* We know we have at least one packet in queue */
409 if (sfq_headdrop(q) &&
410 INET_ECN_set_ce(slot->skblist_next)) {
411 q->stats.forced_mark_head++;
412 break;
413 }
414 if (INET_ECN_set_ce(skb)) {
415 q->stats.forced_mark++;
416 break;
417 }
418 }
419 q->stats.forced_drop++;
420 goto congestion_drop;
421 }
422 }
423
424 if (slot->qlen >= q->maxdepth) {
425congestion_drop:
426 if (!sfq_headdrop(q))
427 return qdisc_drop(skb, sch, to_free);
428
429 /* We know we have at least one packet in queue */
430 head = slot_dequeue_head(slot);
431 delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
432 sch->qstats.backlog -= delta;
433 slot->backlog -= delta;
434 qdisc_drop(head, sch, to_free);
435
436 slot_queue_add(slot, skb);
437 return NET_XMIT_CN;
438 }
439
440enqueue:
441 qdisc_qstats_backlog_inc(sch, skb);
442 slot->backlog += qdisc_pkt_len(skb);
443 slot_queue_add(slot, skb);
444 sfq_inc(q, x);
445 if (slot->qlen == 1) { /* The flow is new */
446 if (q->tail == NULL) { /* It is the first flow */
447 slot->next = x;
448 } else {
449 slot->next = q->tail->next;
450 q->tail->next = x;
451 }
452 /* We put this flow at the end of our flow list.
453 * This might sound unfair for a new flow to wait after old ones,
454 * but we could endup servicing new flows only, and freeze old ones.
455 */
456 q->tail = slot;
457 /* We could use a bigger initial quantum for new flows */
458 slot->allot = q->scaled_quantum;
459 }
460 if (++sch->q.qlen <= q->limit)
461 return NET_XMIT_SUCCESS;
462
463 qlen = slot->qlen;
464 dropped = sfq_drop(sch);
465 /* Return Congestion Notification only if we dropped a packet
466 * from this flow.
467 */
468 if (qlen != slot->qlen)
469 return NET_XMIT_CN;
470
471 /* As we dropped a packet, better let upper stack know this */
472 qdisc_tree_reduce_backlog(sch, 1, dropped);
473 return NET_XMIT_SUCCESS;
474}
475
476static struct sk_buff *
477sfq_dequeue(struct Qdisc *sch)
478{
479 struct sfq_sched_data *q = qdisc_priv(sch);
480 struct sk_buff *skb;
481 sfq_index a, next_a;
482 struct sfq_slot *slot;
483
484 /* No active slots */
485 if (q->tail == NULL)
486 return NULL;
487
488next_slot:
489 a = q->tail->next;
490 slot = &q->slots[a];
491 if (slot->allot <= 0) {
492 q->tail = slot;
493 slot->allot += q->scaled_quantum;
494 goto next_slot;
495 }
496 skb = slot_dequeue_head(slot);
497 sfq_dec(q, a);
498 qdisc_bstats_update(sch, skb);
499 sch->q.qlen--;
500 qdisc_qstats_backlog_dec(sch, skb);
501 slot->backlog -= qdisc_pkt_len(skb);
502 /* Is the slot empty? */
503 if (slot->qlen == 0) {
504 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
505 next_a = slot->next;
506 if (a == next_a) {
507 q->tail = NULL; /* no more active slots */
508 return skb;
509 }
510 q->tail->next = next_a;
511 } else {
512 slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
513 }
514 return skb;
515}
516
517static void
518sfq_reset(struct Qdisc *sch)
519{
520 struct sk_buff *skb;
521
522 while ((skb = sfq_dequeue(sch)) != NULL)
523 rtnl_kfree_skbs(skb, skb);
524}
525
526/*
527 * When q->perturbation is changed, we rehash all queued skbs
528 * to avoid OOO (Out Of Order) effects.
529 * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
530 * counters.
531 */
532static void sfq_rehash(struct Qdisc *sch)
533{
534 struct sfq_sched_data *q = qdisc_priv(sch);
535 struct sk_buff *skb;
536 int i;
537 struct sfq_slot *slot;
538 struct sk_buff_head list;
539 int dropped = 0;
540 unsigned int drop_len = 0;
541
542 __skb_queue_head_init(&list);
543
544 for (i = 0; i < q->maxflows; i++) {
545 slot = &q->slots[i];
546 if (!slot->qlen)
547 continue;
548 while (slot->qlen) {
549 skb = slot_dequeue_head(slot);
550 sfq_dec(q, i);
551 __skb_queue_tail(&list, skb);
552 }
553 slot->backlog = 0;
554 red_set_vars(&slot->vars);
555 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
556 }
557 q->tail = NULL;
558
559 while ((skb = __skb_dequeue(&list)) != NULL) {
560 unsigned int hash = sfq_hash(q, skb);
561 sfq_index x = q->ht[hash];
562
563 slot = &q->slots[x];
564 if (x == SFQ_EMPTY_SLOT) {
565 x = q->dep[0].next; /* get a free slot */
566 if (x >= SFQ_MAX_FLOWS) {
567drop:
568 qdisc_qstats_backlog_dec(sch, skb);
569 drop_len += qdisc_pkt_len(skb);
570 kfree_skb(skb);
571 dropped++;
572 continue;
573 }
574 q->ht[hash] = x;
575 slot = &q->slots[x];
576 slot->hash = hash;
577 }
578 if (slot->qlen >= q->maxdepth)
579 goto drop;
580 slot_queue_add(slot, skb);
581 if (q->red_parms)
582 slot->vars.qavg = red_calc_qavg(q->red_parms,
583 &slot->vars,
584 slot->backlog);
585 slot->backlog += qdisc_pkt_len(skb);
586 sfq_inc(q, x);
587 if (slot->qlen == 1) { /* The flow is new */
588 if (q->tail == NULL) { /* It is the first flow */
589 slot->next = x;
590 } else {
591 slot->next = q->tail->next;
592 q->tail->next = x;
593 }
594 q->tail = slot;
595 slot->allot = q->scaled_quantum;
596 }
597 }
598 sch->q.qlen -= dropped;
599 qdisc_tree_reduce_backlog(sch, dropped, drop_len);
600}
601
602static void sfq_perturbation(unsigned long arg)
603{
604 struct Qdisc *sch = (struct Qdisc *)arg;
605 struct sfq_sched_data *q = qdisc_priv(sch);
606 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
607
608 spin_lock(root_lock);
609 q->perturbation = prandom_u32();
610 if (!q->filter_list && q->tail)
611 sfq_rehash(sch);
612 spin_unlock(root_lock);
613
614 if (q->perturb_period)
615 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
616}
617
618static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
619{
620 struct sfq_sched_data *q = qdisc_priv(sch);
621 struct tc_sfq_qopt *ctl = nla_data(opt);
622 struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
623 unsigned int qlen, dropped = 0;
624 struct red_parms *p = NULL;
625
626 if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
627 return -EINVAL;
628 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
629 ctl_v1 = nla_data(opt);
630 if (ctl->divisor &&
631 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
632 return -EINVAL;
633 if (ctl_v1 && ctl_v1->qth_min) {
634 p = kmalloc(sizeof(*p), GFP_KERNEL);
635 if (!p)
636 return -ENOMEM;
637 }
638 sch_tree_lock(sch);
639 if (ctl->quantum) {
640 q->quantum = ctl->quantum;
641 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
642 }
643 q->perturb_period = ctl->perturb_period * HZ;
644 if (ctl->flows)
645 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
646 if (ctl->divisor) {
647 q->divisor = ctl->divisor;
648 q->maxflows = min_t(u32, q->maxflows, q->divisor);
649 }
650 if (ctl_v1) {
651 if (ctl_v1->depth)
652 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
653 if (p) {
654 swap(q->red_parms, p);
655 red_set_parms(q->red_parms,
656 ctl_v1->qth_min, ctl_v1->qth_max,
657 ctl_v1->Wlog,
658 ctl_v1->Plog, ctl_v1->Scell_log,
659 NULL,
660 ctl_v1->max_P);
661 }
662 q->flags = ctl_v1->flags;
663 q->headdrop = ctl_v1->headdrop;
664 }
665 if (ctl->limit) {
666 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
667 q->maxflows = min_t(u32, q->maxflows, q->limit);
668 }
669
670 qlen = sch->q.qlen;
671 while (sch->q.qlen > q->limit)
672 dropped += sfq_drop(sch);
673 qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);
674
675 del_timer(&q->perturb_timer);
676 if (q->perturb_period) {
677 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
678 q->perturbation = prandom_u32();
679 }
680 sch_tree_unlock(sch);
681 kfree(p);
682 return 0;
683}
684
685static void *sfq_alloc(size_t sz)
686{
687 void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN);
688
689 if (!ptr)
690 ptr = vmalloc(sz);
691 return ptr;
692}
693
694static void sfq_free(void *addr)
695{
696 kvfree(addr);
697}
698
699static void sfq_destroy(struct Qdisc *sch)
700{
701 struct sfq_sched_data *q = qdisc_priv(sch);
702
703 tcf_destroy_chain(&q->filter_list);
704 q->perturb_period = 0;
705 del_timer_sync(&q->perturb_timer);
706 sfq_free(q->ht);
707 sfq_free(q->slots);
708 kfree(q->red_parms);
709}
710
711static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
712{
713 struct sfq_sched_data *q = qdisc_priv(sch);
714 int i;
715
716 q->perturb_timer.function = sfq_perturbation;
717 q->perturb_timer.data = (unsigned long)sch;
718 init_timer_deferrable(&q->perturb_timer);
719
720 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
721 q->dep[i].next = i + SFQ_MAX_FLOWS;
722 q->dep[i].prev = i + SFQ_MAX_FLOWS;
723 }
724
725 q->limit = SFQ_MAX_DEPTH;
726 q->maxdepth = SFQ_MAX_DEPTH;
727 q->cur_depth = 0;
728 q->tail = NULL;
729 q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
730 q->maxflows = SFQ_DEFAULT_FLOWS;
731 q->quantum = psched_mtu(qdisc_dev(sch));
732 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
733 q->perturb_period = 0;
734 q->perturbation = prandom_u32();
735
736 if (opt) {
737 int err = sfq_change(sch, opt);
738 if (err)
739 return err;
740 }
741
742 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
743 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
744 if (!q->ht || !q->slots) {
745 sfq_destroy(sch);
746 return -ENOMEM;
747 }
748 for (i = 0; i < q->divisor; i++)
749 q->ht[i] = SFQ_EMPTY_SLOT;
750
751 for (i = 0; i < q->maxflows; i++) {
752 slot_queue_init(&q->slots[i]);
753 sfq_link(q, i);
754 }
755 if (q->limit >= 1)
756 sch->flags |= TCQ_F_CAN_BYPASS;
757 else
758 sch->flags &= ~TCQ_F_CAN_BYPASS;
759 return 0;
760}
761
762static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
763{
764 struct sfq_sched_data *q = qdisc_priv(sch);
765 unsigned char *b = skb_tail_pointer(skb);
766 struct tc_sfq_qopt_v1 opt;
767 struct red_parms *p = q->red_parms;
768
769 memset(&opt, 0, sizeof(opt));
770 opt.v0.quantum = q->quantum;
771 opt.v0.perturb_period = q->perturb_period / HZ;
772 opt.v0.limit = q->limit;
773 opt.v0.divisor = q->divisor;
774 opt.v0.flows = q->maxflows;
775 opt.depth = q->maxdepth;
776 opt.headdrop = q->headdrop;
777
778 if (p) {
779 opt.qth_min = p->qth_min >> p->Wlog;
780 opt.qth_max = p->qth_max >> p->Wlog;
781 opt.Wlog = p->Wlog;
782 opt.Plog = p->Plog;
783 opt.Scell_log = p->Scell_log;
784 opt.max_P = p->max_P;
785 }
786 memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
787 opt.flags = q->flags;
788
789 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
790 goto nla_put_failure;
791
792 return skb->len;
793
794nla_put_failure:
795 nlmsg_trim(skb, b);
796 return -1;
797}
798
799static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
800{
801 return NULL;
802}
803
804static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
805{
806 return 0;
807}
808
809static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
810 u32 classid)
811{
812 /* we cannot bypass queue discipline anymore */
813 sch->flags &= ~TCQ_F_CAN_BYPASS;
814 return 0;
815}
816
817static void sfq_put(struct Qdisc *q, unsigned long cl)
818{
819}
820
821static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch,
822 unsigned long cl)
823{
824 struct sfq_sched_data *q = qdisc_priv(sch);
825
826 if (cl)
827 return NULL;
828 return &q->filter_list;
829}
830
831static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
832 struct sk_buff *skb, struct tcmsg *tcm)
833{
834 tcm->tcm_handle |= TC_H_MIN(cl);
835 return 0;
836}
837
838static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
839 struct gnet_dump *d)
840{
841 struct sfq_sched_data *q = qdisc_priv(sch);
842 sfq_index idx = q->ht[cl - 1];
843 struct gnet_stats_queue qs = { 0 };
844 struct tc_sfq_xstats xstats = { 0 };
845
846 if (idx != SFQ_EMPTY_SLOT) {
847 const struct sfq_slot *slot = &q->slots[idx];
848
849 xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
850 qs.qlen = slot->qlen;
851 qs.backlog = slot->backlog;
852 }
853 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
854 return -1;
855 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
856}
857
858static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
859{
860 struct sfq_sched_data *q = qdisc_priv(sch);
861 unsigned int i;
862
863 if (arg->stop)
864 return;
865
866 for (i = 0; i < q->divisor; i++) {
867 if (q->ht[i] == SFQ_EMPTY_SLOT ||
868 arg->count < arg->skip) {
869 arg->count++;
870 continue;
871 }
872 if (arg->fn(sch, i + 1, arg) < 0) {
873 arg->stop = 1;
874 break;
875 }
876 arg->count++;
877 }
878}
879
880static const struct Qdisc_class_ops sfq_class_ops = {
881 .leaf = sfq_leaf,
882 .get = sfq_get,
883 .put = sfq_put,
884 .tcf_chain = sfq_find_tcf,
885 .bind_tcf = sfq_bind,
886 .unbind_tcf = sfq_put,
887 .dump = sfq_dump_class,
888 .dump_stats = sfq_dump_class_stats,
889 .walk = sfq_walk,
890};
891
892static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
893 .cl_ops = &sfq_class_ops,
894 .id = "sfq",
895 .priv_size = sizeof(struct sfq_sched_data),
896 .enqueue = sfq_enqueue,
897 .dequeue = sfq_dequeue,
898 .peek = qdisc_peek_dequeued,
899 .init = sfq_init,
900 .reset = sfq_reset,
901 .destroy = sfq_destroy,
902 .change = NULL,
903 .dump = sfq_dump,
904 .owner = THIS_MODULE,
905};
906
907static int __init sfq_module_init(void)
908{
909 return register_qdisc(&sfq_qdisc_ops);
910}
911static void __exit sfq_module_exit(void)
912{
913 unregister_qdisc(&sfq_qdisc_ops);
914}
915module_init(sfq_module_init)
916module_exit(sfq_module_exit)
917MODULE_LICENSE("GPL");
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