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act_mirred: fix a race condition on mirred_list
[deliverable/linux.git] / net / sched / sch_sfq.c
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 */
90 typedef 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 */
98 struct sfq_head {
99 sfq_index next;
100 sfq_index prev;
101 };
102
103 struct 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
116 struct 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 */
151 static 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
158 static 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
164 static 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 */
202 static 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
227 static 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
240 static 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 */
256 static 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 */
267 static 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
277 static 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) */
284 static 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
292 static 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];
304 drop:
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 */
329 static 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 */
335 static 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
340 static int sfq_headdrop(const struct sfq_sched_data *q)
341 {
342 return q->headdrop;
343 }
344
345 static int
346 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
347 {
348 struct sfq_sched_data *q = qdisc_priv(sch);
349 unsigned int hash;
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);
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) {
425 congestion_drop:
426 if (!sfq_headdrop(q))
427 return qdisc_drop(skb, sch);
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);
435
436 slot_queue_add(slot, skb);
437 return NET_XMIT_CN;
438 }
439
440 enqueue:
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 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_decrease_qlen(sch, 1);
473 return NET_XMIT_SUCCESS;
474 }
475
476 static struct sk_buff *
477 sfq_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
488 next_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
517 static void
518 sfq_reset(struct Qdisc *sch)
519 {
520 struct sk_buff *skb;
521
522 while ((skb = sfq_dequeue(sch)) != NULL)
523 kfree_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 */
532 static 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
541 __skb_queue_head_init(&list);
542
543 for (i = 0; i < q->maxflows; i++) {
544 slot = &q->slots[i];
545 if (!slot->qlen)
546 continue;
547 while (slot->qlen) {
548 skb = slot_dequeue_head(slot);
549 sfq_dec(q, i);
550 __skb_queue_tail(&list, skb);
551 }
552 slot->backlog = 0;
553 red_set_vars(&slot->vars);
554 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
555 }
556 q->tail = NULL;
557
558 while ((skb = __skb_dequeue(&list)) != NULL) {
559 unsigned int hash = sfq_hash(q, skb);
560 sfq_index x = q->ht[hash];
561
562 slot = &q->slots[x];
563 if (x == SFQ_EMPTY_SLOT) {
564 x = q->dep[0].next; /* get a free slot */
565 if (x >= SFQ_MAX_FLOWS) {
566 drop:
567 qdisc_qstats_backlog_dec(sch, skb);
568 kfree_skb(skb);
569 dropped++;
570 continue;
571 }
572 q->ht[hash] = x;
573 slot = &q->slots[x];
574 slot->hash = hash;
575 }
576 if (slot->qlen >= q->maxdepth)
577 goto drop;
578 slot_queue_add(slot, skb);
579 if (q->red_parms)
580 slot->vars.qavg = red_calc_qavg(q->red_parms,
581 &slot->vars,
582 slot->backlog);
583 slot->backlog += qdisc_pkt_len(skb);
584 sfq_inc(q, x);
585 if (slot->qlen == 1) { /* The flow is new */
586 if (q->tail == NULL) { /* It is the first flow */
587 slot->next = x;
588 } else {
589 slot->next = q->tail->next;
590 q->tail->next = x;
591 }
592 q->tail = slot;
593 slot->allot = q->scaled_quantum;
594 }
595 }
596 sch->q.qlen -= dropped;
597 qdisc_tree_decrease_qlen(sch, dropped);
598 }
599
600 static void sfq_perturbation(unsigned long arg)
601 {
602 struct Qdisc *sch = (struct Qdisc *)arg;
603 struct sfq_sched_data *q = qdisc_priv(sch);
604 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
605
606 spin_lock(root_lock);
607 q->perturbation = prandom_u32();
608 if (!q->filter_list && q->tail)
609 sfq_rehash(sch);
610 spin_unlock(root_lock);
611
612 if (q->perturb_period)
613 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
614 }
615
616 static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
617 {
618 struct sfq_sched_data *q = qdisc_priv(sch);
619 struct tc_sfq_qopt *ctl = nla_data(opt);
620 struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
621 unsigned int qlen;
622 struct red_parms *p = NULL;
623
624 if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
625 return -EINVAL;
626 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
627 ctl_v1 = nla_data(opt);
628 if (ctl->divisor &&
629 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
630 return -EINVAL;
631 if (ctl_v1 && ctl_v1->qth_min) {
632 p = kmalloc(sizeof(*p), GFP_KERNEL);
633 if (!p)
634 return -ENOMEM;
635 }
636 sch_tree_lock(sch);
637 if (ctl->quantum) {
638 q->quantum = ctl->quantum;
639 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
640 }
641 q->perturb_period = ctl->perturb_period * HZ;
642 if (ctl->flows)
643 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
644 if (ctl->divisor) {
645 q->divisor = ctl->divisor;
646 q->maxflows = min_t(u32, q->maxflows, q->divisor);
647 }
648 if (ctl_v1) {
649 if (ctl_v1->depth)
650 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
651 if (p) {
652 swap(q->red_parms, p);
653 red_set_parms(q->red_parms,
654 ctl_v1->qth_min, ctl_v1->qth_max,
655 ctl_v1->Wlog,
656 ctl_v1->Plog, ctl_v1->Scell_log,
657 NULL,
658 ctl_v1->max_P);
659 }
660 q->flags = ctl_v1->flags;
661 q->headdrop = ctl_v1->headdrop;
662 }
663 if (ctl->limit) {
664 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
665 q->maxflows = min_t(u32, q->maxflows, q->limit);
666 }
667
668 qlen = sch->q.qlen;
669 while (sch->q.qlen > q->limit)
670 sfq_drop(sch);
671 qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
672
673 del_timer(&q->perturb_timer);
674 if (q->perturb_period) {
675 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
676 q->perturbation = prandom_u32();
677 }
678 sch_tree_unlock(sch);
679 kfree(p);
680 return 0;
681 }
682
683 static void *sfq_alloc(size_t sz)
684 {
685 void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN);
686
687 if (!ptr)
688 ptr = vmalloc(sz);
689 return ptr;
690 }
691
692 static void sfq_free(void *addr)
693 {
694 kvfree(addr);
695 }
696
697 static void sfq_destroy(struct Qdisc *sch)
698 {
699 struct sfq_sched_data *q = qdisc_priv(sch);
700
701 tcf_destroy_chain(&q->filter_list);
702 q->perturb_period = 0;
703 del_timer_sync(&q->perturb_timer);
704 sfq_free(q->ht);
705 sfq_free(q->slots);
706 kfree(q->red_parms);
707 }
708
709 static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
710 {
711 struct sfq_sched_data *q = qdisc_priv(sch);
712 int i;
713
714 q->perturb_timer.function = sfq_perturbation;
715 q->perturb_timer.data = (unsigned long)sch;
716 init_timer_deferrable(&q->perturb_timer);
717
718 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
719 q->dep[i].next = i + SFQ_MAX_FLOWS;
720 q->dep[i].prev = i + SFQ_MAX_FLOWS;
721 }
722
723 q->limit = SFQ_MAX_DEPTH;
724 q->maxdepth = SFQ_MAX_DEPTH;
725 q->cur_depth = 0;
726 q->tail = NULL;
727 q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
728 q->maxflows = SFQ_DEFAULT_FLOWS;
729 q->quantum = psched_mtu(qdisc_dev(sch));
730 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
731 q->perturb_period = 0;
732 q->perturbation = prandom_u32();
733
734 if (opt) {
735 int err = sfq_change(sch, opt);
736 if (err)
737 return err;
738 }
739
740 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
741 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
742 if (!q->ht || !q->slots) {
743 sfq_destroy(sch);
744 return -ENOMEM;
745 }
746 for (i = 0; i < q->divisor; i++)
747 q->ht[i] = SFQ_EMPTY_SLOT;
748
749 for (i = 0; i < q->maxflows; i++) {
750 slot_queue_init(&q->slots[i]);
751 sfq_link(q, i);
752 }
753 if (q->limit >= 1)
754 sch->flags |= TCQ_F_CAN_BYPASS;
755 else
756 sch->flags &= ~TCQ_F_CAN_BYPASS;
757 return 0;
758 }
759
760 static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
761 {
762 struct sfq_sched_data *q = qdisc_priv(sch);
763 unsigned char *b = skb_tail_pointer(skb);
764 struct tc_sfq_qopt_v1 opt;
765 struct red_parms *p = q->red_parms;
766
767 memset(&opt, 0, sizeof(opt));
768 opt.v0.quantum = q->quantum;
769 opt.v0.perturb_period = q->perturb_period / HZ;
770 opt.v0.limit = q->limit;
771 opt.v0.divisor = q->divisor;
772 opt.v0.flows = q->maxflows;
773 opt.depth = q->maxdepth;
774 opt.headdrop = q->headdrop;
775
776 if (p) {
777 opt.qth_min = p->qth_min >> p->Wlog;
778 opt.qth_max = p->qth_max >> p->Wlog;
779 opt.Wlog = p->Wlog;
780 opt.Plog = p->Plog;
781 opt.Scell_log = p->Scell_log;
782 opt.max_P = p->max_P;
783 }
784 memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
785 opt.flags = q->flags;
786
787 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
788 goto nla_put_failure;
789
790 return skb->len;
791
792 nla_put_failure:
793 nlmsg_trim(skb, b);
794 return -1;
795 }
796
797 static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
798 {
799 return NULL;
800 }
801
802 static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
803 {
804 return 0;
805 }
806
807 static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
808 u32 classid)
809 {
810 /* we cannot bypass queue discipline anymore */
811 sch->flags &= ~TCQ_F_CAN_BYPASS;
812 return 0;
813 }
814
815 static void sfq_put(struct Qdisc *q, unsigned long cl)
816 {
817 }
818
819 static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch,
820 unsigned long cl)
821 {
822 struct sfq_sched_data *q = qdisc_priv(sch);
823
824 if (cl)
825 return NULL;
826 return &q->filter_list;
827 }
828
829 static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
830 struct sk_buff *skb, struct tcmsg *tcm)
831 {
832 tcm->tcm_handle |= TC_H_MIN(cl);
833 return 0;
834 }
835
836 static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
837 struct gnet_dump *d)
838 {
839 struct sfq_sched_data *q = qdisc_priv(sch);
840 sfq_index idx = q->ht[cl - 1];
841 struct gnet_stats_queue qs = { 0 };
842 struct tc_sfq_xstats xstats = { 0 };
843
844 if (idx != SFQ_EMPTY_SLOT) {
845 const struct sfq_slot *slot = &q->slots[idx];
846
847 xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
848 qs.qlen = slot->qlen;
849 qs.backlog = slot->backlog;
850 }
851 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
852 return -1;
853 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
854 }
855
856 static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
857 {
858 struct sfq_sched_data *q = qdisc_priv(sch);
859 unsigned int i;
860
861 if (arg->stop)
862 return;
863
864 for (i = 0; i < q->divisor; i++) {
865 if (q->ht[i] == SFQ_EMPTY_SLOT ||
866 arg->count < arg->skip) {
867 arg->count++;
868 continue;
869 }
870 if (arg->fn(sch, i + 1, arg) < 0) {
871 arg->stop = 1;
872 break;
873 }
874 arg->count++;
875 }
876 }
877
878 static const struct Qdisc_class_ops sfq_class_ops = {
879 .leaf = sfq_leaf,
880 .get = sfq_get,
881 .put = sfq_put,
882 .tcf_chain = sfq_find_tcf,
883 .bind_tcf = sfq_bind,
884 .unbind_tcf = sfq_put,
885 .dump = sfq_dump_class,
886 .dump_stats = sfq_dump_class_stats,
887 .walk = sfq_walk,
888 };
889
890 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
891 .cl_ops = &sfq_class_ops,
892 .id = "sfq",
893 .priv_size = sizeof(struct sfq_sched_data),
894 .enqueue = sfq_enqueue,
895 .dequeue = sfq_dequeue,
896 .peek = qdisc_peek_dequeued,
897 .drop = sfq_drop,
898 .init = sfq_init,
899 .reset = sfq_reset,
900 .destroy = sfq_destroy,
901 .change = NULL,
902 .dump = sfq_dump,
903 .owner = THIS_MODULE,
904 };
905
906 static int __init sfq_module_init(void)
907 {
908 return register_qdisc(&sfq_qdisc_ops);
909 }
910 static void __exit sfq_module_exit(void)
911 {
912 unregister_qdisc(&sfq_qdisc_ops);
913 }
914 module_init(sfq_module_init)
915 module_exit(sfq_module_exit)
916 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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