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rapidio/tsi721: fix bug in register offset definitions
[linux-2.6.git] / net / sched / sch_sfq.c
blob60d47180f0432e0d65c92ef5a6f6cf865b29a3c0
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/flow_keys.h>
27 #include <net/red.h>
28
29
30 /* Stochastic Fairness Queuing algorithm.
31 =======================================
32
33 Source:
34 Paul E. McKenney "Stochastic Fairness Queuing",
35 IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
36
37 Paul E. McKenney "Stochastic Fairness Queuing",
38 "Interworking: Research and Experience", v.2, 1991, p.113-131.
39
40
41 See also:
42 M. Shreedhar and George Varghese "Efficient Fair
43 Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
44
45
46 This is not the thing that is usually called (W)FQ nowadays.
47 It does not use any timestamp mechanism, but instead
48 processes queues in round-robin order.
49
50 ADVANTAGE:
51
52 - It is very cheap. Both CPU and memory requirements are minimal.
53
54 DRAWBACKS:
55
56 - "Stochastic" -> It is not 100% fair.
57 When hash collisions occur, several flows are considered as one.
58
59 - "Round-robin" -> It introduces larger delays than virtual clock
60 based schemes, and should not be used for isolating interactive
61 traffic from non-interactive. It means, that this scheduler
62 should be used as leaf of CBQ or P3, which put interactive traffic
63 to higher priority band.
64
65 We still need true WFQ for top level CSZ, but using WFQ
66 for the best effort traffic is absolutely pointless:
67 SFQ is superior for this purpose.
68
69 IMPLEMENTATION:
70 This implementation limits :
71 - maximal queue length per flow to 127 packets.
72 - max mtu to 2^18-1;
73 - max 65408 flows,
74 - number of hash buckets to 65536.
75
76 It is easy to increase these values, but not in flight. */
77
78 #define SFQ_MAX_DEPTH 127 /* max number of packets per flow */
79 #define SFQ_DEFAULT_FLOWS 128
80 #define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
81 #define SFQ_EMPTY_SLOT 0xffff
82 #define SFQ_DEFAULT_HASH_DIVISOR 1024
83
84 /* We use 16 bits to store allot, and want to handle packets up to 64K
85 * Scale allot by 8 (1<<3) so that no overflow occurs.
86 */
87 #define SFQ_ALLOT_SHIFT 3
88 #define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
89
90 /* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
91 typedef u16 sfq_index;
92
93 /*
94 * We dont use pointers to save space.
95 * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
96 * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
97 * are 'pointers' to dep[] array
98 */
99 struct sfq_head {
100 sfq_index next;
101 sfq_index prev;
102 };
103
104 struct sfq_slot {
105 struct sk_buff *skblist_next;
106 struct sk_buff *skblist_prev;
107 sfq_index qlen; /* number of skbs in skblist */
108 sfq_index next; /* next slot in sfq RR chain */
109 struct sfq_head dep; /* anchor in dep[] chains */
110 unsigned short hash; /* hash value (index in ht[]) */
111 short allot; /* credit for this slot */
112
113 unsigned int backlog;
114 struct red_vars vars;
115 };
116
117 struct sfq_sched_data {
118 /* frequently used fields */
119 int limit; /* limit of total number of packets in this qdisc */
120 unsigned int divisor; /* number of slots in hash table */
121 u8 headdrop;
122 u8 maxdepth; /* limit of packets per flow */
123
124 u32 perturbation;
125 u8 cur_depth; /* depth of longest slot */
126 u8 flags;
127 unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
128 struct tcf_proto *filter_list;
129 sfq_index *ht; /* Hash table ('divisor' slots) */
130 struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
131
132 struct red_parms *red_parms;
133 struct tc_sfqred_stats stats;
134 struct sfq_slot *tail; /* current slot in round */
135
136 struct sfq_head dep[SFQ_MAX_DEPTH + 1];
137 /* Linked lists of slots, indexed by depth
138 * dep[0] : list of unused flows
139 * dep[1] : list of flows with 1 packet
140 * dep[X] : list of flows with X packets
141 */
142
143 unsigned int maxflows; /* number of flows in flows array */
144 int perturb_period;
145 unsigned int quantum; /* Allotment per round: MUST BE >= MTU */
146 struct timer_list perturb_timer;
147 };
148
149 /*
150 * sfq_head are either in a sfq_slot or in dep[] array
151 */
152 static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
153 {
154 if (val < SFQ_MAX_FLOWS)
155 return &q->slots[val].dep;
156 return &q->dep[val - SFQ_MAX_FLOWS];
157 }
158
159 /*
160 * In order to be able to quickly rehash our queue when timer changes
161 * q->perturbation, we store flow_keys in skb->cb[]
162 */
163 struct sfq_skb_cb {
164 struct flow_keys keys;
165 };
166
167 static inline struct sfq_skb_cb *sfq_skb_cb(const struct sk_buff *skb)
168 {
169 qdisc_cb_private_validate(skb, sizeof(struct sfq_skb_cb));
170 return (struct sfq_skb_cb *)qdisc_skb_cb(skb)->data;
171 }
172
173 static unsigned int sfq_hash(const struct sfq_sched_data *q,
174 const struct sk_buff *skb)
175 {
176 const struct flow_keys *keys = &sfq_skb_cb(skb)->keys;
177 unsigned int hash;
178
179 hash = jhash_3words((__force u32)keys->dst,
180 (__force u32)keys->src ^ keys->ip_proto,
181 (__force u32)keys->ports, q->perturbation);
182 return hash & (q->divisor - 1);
183 }
184
185 static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
186 int *qerr)
187 {
188 struct sfq_sched_data *q = qdisc_priv(sch);
189 struct tcf_result res;
190 int result;
191
192 if (TC_H_MAJ(skb->priority) == sch->handle &&
193 TC_H_MIN(skb->priority) > 0 &&
194 TC_H_MIN(skb->priority) <= q->divisor)
195 return TC_H_MIN(skb->priority);
196
197 if (!q->filter_list) {
198 skb_flow_dissect(skb, &sfq_skb_cb(skb)->keys);
199 return sfq_hash(q, skb) + 1;
200 }
201
202 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
203 result = tc_classify(skb, q->filter_list, &res);
204 if (result >= 0) {
205 #ifdef CONFIG_NET_CLS_ACT
206 switch (result) {
207 case TC_ACT_STOLEN:
208 case TC_ACT_QUEUED:
209 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
210 case TC_ACT_SHOT:
211 return 0;
212 }
213 #endif
214 if (TC_H_MIN(res.classid) <= q->divisor)
215 return TC_H_MIN(res.classid);
216 }
217 return 0;
218 }
219
220 /*
221 * x : slot number [0 .. SFQ_MAX_FLOWS - 1]
222 */
223 static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
224 {
225 sfq_index p, n;
226 struct sfq_slot *slot = &q->slots[x];
227 int qlen = slot->qlen;
228
229 p = qlen + SFQ_MAX_FLOWS;
230 n = q->dep[qlen].next;
231
232 slot->dep.next = n;
233 slot->dep.prev = p;
234
235 q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */
236 sfq_dep_head(q, n)->prev = x;
237 }
238
239 #define sfq_unlink(q, x, n, p) \
240 n = q->slots[x].dep.next; \
241 p = q->slots[x].dep.prev; \
242 sfq_dep_head(q, p)->next = n; \
243 sfq_dep_head(q, n)->prev = p
244
245
246 static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
247 {
248 sfq_index p, n;
249 int d;
250
251 sfq_unlink(q, x, n, p);
252
253 d = q->slots[x].qlen--;
254 if (n == p && q->cur_depth == d)
255 q->cur_depth--;
256 sfq_link(q, x);
257 }
258
259 static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
260 {
261 sfq_index p, n;
262 int d;
263
264 sfq_unlink(q, x, n, p);
265
266 d = ++q->slots[x].qlen;
267 if (q->cur_depth < d)
268 q->cur_depth = d;
269 sfq_link(q, x);
270 }
271
272 /* helper functions : might be changed when/if skb use a standard list_head */
273
274 /* remove one skb from tail of slot queue */
275 static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
276 {
277 struct sk_buff *skb = slot->skblist_prev;
278
279 slot->skblist_prev = skb->prev;
280 skb->prev->next = (struct sk_buff *)slot;
281 skb->next = skb->prev = NULL;
282 return skb;
283 }
284
285 /* remove one skb from head of slot queue */
286 static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
287 {
288 struct sk_buff *skb = slot->skblist_next;
289
290 slot->skblist_next = skb->next;
291 skb->next->prev = (struct sk_buff *)slot;
292 skb->next = skb->prev = NULL;
293 return skb;
294 }
295
296 static inline void slot_queue_init(struct sfq_slot *slot)
297 {
298 memset(slot, 0, sizeof(*slot));
299 slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
300 }
301
302 /* add skb to slot queue (tail add) */
303 static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
304 {
305 skb->prev = slot->skblist_prev;
306 skb->next = (struct sk_buff *)slot;
307 slot->skblist_prev->next = skb;
308 slot->skblist_prev = skb;
309 }
310
311 #define slot_queue_walk(slot, skb) \
312 for (skb = slot->skblist_next; \
313 skb != (struct sk_buff *)slot; \
314 skb = skb->next)
315
316 static unsigned int sfq_drop(struct Qdisc *sch)
317 {
318 struct sfq_sched_data *q = qdisc_priv(sch);
319 sfq_index x, d = q->cur_depth;
320 struct sk_buff *skb;
321 unsigned int len;
322 struct sfq_slot *slot;
323
324 /* Queue is full! Find the longest slot and drop tail packet from it */
325 if (d > 1) {
326 x = q->dep[d].next;
327 slot = &q->slots[x];
328 drop:
329 skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
330 len = qdisc_pkt_len(skb);
331 slot->backlog -= len;
332 sfq_dec(q, x);
333 kfree_skb(skb);
334 sch->q.qlen--;
335 sch->qstats.drops++;
336 sch->qstats.backlog -= len;
337 return len;
338 }
339
340 if (d == 1) {
341 /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
342 x = q->tail->next;
343 slot = &q->slots[x];
344 q->tail->next = slot->next;
345 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
346 goto drop;
347 }
348
349 return 0;
350 }
351
352 /* Is ECN parameter configured */
353 static int sfq_prob_mark(const struct sfq_sched_data *q)
354 {
355 return q->flags & TC_RED_ECN;
356 }
357
358 /* Should packets over max threshold just be marked */
359 static int sfq_hard_mark(const struct sfq_sched_data *q)
360 {
361 return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
362 }
363
364 static int sfq_headdrop(const struct sfq_sched_data *q)
365 {
366 return q->headdrop;
367 }
368
369 static int
370 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
371 {
372 struct sfq_sched_data *q = qdisc_priv(sch);
373 unsigned int hash;
374 sfq_index x, qlen;
375 struct sfq_slot *slot;
376 int uninitialized_var(ret);
377 struct sk_buff *head;
378 int delta;
379
380 hash = sfq_classify(skb, sch, &ret);
381 if (hash == 0) {
382 if (ret & __NET_XMIT_BYPASS)
383 sch->qstats.drops++;
384 kfree_skb(skb);
385 return ret;
386 }
387 hash--;
388
389 x = q->ht[hash];
390 slot = &q->slots[x];
391 if (x == SFQ_EMPTY_SLOT) {
392 x = q->dep[0].next; /* get a free slot */
393 if (x >= SFQ_MAX_FLOWS)
394 return qdisc_drop(skb, sch);
395 q->ht[hash] = x;
396 slot = &q->slots[x];
397 slot->hash = hash;
398 slot->backlog = 0; /* should already be 0 anyway... */
399 red_set_vars(&slot->vars);
400 goto enqueue;
401 }
402 if (q->red_parms) {
403 slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
404 &slot->vars,
405 slot->backlog);
406 switch (red_action(q->red_parms,
407 &slot->vars,
408 slot->vars.qavg)) {
409 case RED_DONT_MARK:
410 break;
411
412 case RED_PROB_MARK:
413 sch->qstats.overlimits++;
414 if (sfq_prob_mark(q)) {
415 /* We know we have at least one packet in queue */
416 if (sfq_headdrop(q) &&
417 INET_ECN_set_ce(slot->skblist_next)) {
418 q->stats.prob_mark_head++;
419 break;
420 }
421 if (INET_ECN_set_ce(skb)) {
422 q->stats.prob_mark++;
423 break;
424 }
425 }
426 q->stats.prob_drop++;
427 goto congestion_drop;
428
429 case RED_HARD_MARK:
430 sch->qstats.overlimits++;
431 if (sfq_hard_mark(q)) {
432 /* We know we have at least one packet in queue */
433 if (sfq_headdrop(q) &&
434 INET_ECN_set_ce(slot->skblist_next)) {
435 q->stats.forced_mark_head++;
436 break;
437 }
438 if (INET_ECN_set_ce(skb)) {
439 q->stats.forced_mark++;
440 break;
441 }
442 }
443 q->stats.forced_drop++;
444 goto congestion_drop;
445 }
446 }
447
448 if (slot->qlen >= q->maxdepth) {
449 congestion_drop:
450 if (!sfq_headdrop(q))
451 return qdisc_drop(skb, sch);
452
453 /* We know we have at least one packet in queue */
454 head = slot_dequeue_head(slot);
455 delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
456 sch->qstats.backlog -= delta;
457 slot->backlog -= delta;
458 qdisc_drop(head, sch);
459
460 slot_queue_add(slot, skb);
461 return NET_XMIT_CN;
462 }
463
464 enqueue:
465 sch->qstats.backlog += qdisc_pkt_len(skb);
466 slot->backlog += qdisc_pkt_len(skb);
467 slot_queue_add(slot, skb);
468 sfq_inc(q, x);
469 if (slot->qlen == 1) { /* The flow is new */
470 if (q->tail == NULL) { /* It is the first flow */
471 slot->next = x;
472 q->tail = slot;
473 } else {
474 slot->next = q->tail->next;
475 q->tail->next = x;
476 }
477 /* We could use a bigger initial quantum for new flows */
478 slot->allot = q->scaled_quantum;
479 }
480 if (++sch->q.qlen <= q->limit)
481 return NET_XMIT_SUCCESS;
482
483 qlen = slot->qlen;
484 sfq_drop(sch);
485 /* Return Congestion Notification only if we dropped a packet
486 * from this flow.
487 */
488 if (qlen != slot->qlen)
489 return NET_XMIT_CN;
490
491 /* As we dropped a packet, better let upper stack know this */
492 qdisc_tree_decrease_qlen(sch, 1);
493 return NET_XMIT_SUCCESS;
494 }
495
496 static struct sk_buff *
497 sfq_dequeue(struct Qdisc *sch)
498 {
499 struct sfq_sched_data *q = qdisc_priv(sch);
500 struct sk_buff *skb;
501 sfq_index a, next_a;
502 struct sfq_slot *slot;
503
504 /* No active slots */
505 if (q->tail == NULL)
506 return NULL;
507
508 next_slot:
509 a = q->tail->next;
510 slot = &q->slots[a];
511 if (slot->allot <= 0) {
512 q->tail = slot;
513 slot->allot += q->scaled_quantum;
514 goto next_slot;
515 }
516 skb = slot_dequeue_head(slot);
517 sfq_dec(q, a);
518 qdisc_bstats_update(sch, skb);
519 sch->q.qlen--;
520 sch->qstats.backlog -= qdisc_pkt_len(skb);
521 slot->backlog -= qdisc_pkt_len(skb);
522 /* Is the slot empty? */
523 if (slot->qlen == 0) {
524 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
525 next_a = slot->next;
526 if (a == next_a) {
527 q->tail = NULL; /* no more active slots */
528 return skb;
529 }
530 q->tail->next = next_a;
531 } else {
532 slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
533 }
534 return skb;
535 }
536
537 static void
538 sfq_reset(struct Qdisc *sch)
539 {
540 struct sk_buff *skb;
541
542 while ((skb = sfq_dequeue(sch)) != NULL)
543 kfree_skb(skb);
544 }
545
546 /*
547 * When q->perturbation is changed, we rehash all queued skbs
548 * to avoid OOO (Out Of Order) effects.
549 * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
550 * counters.
551 */
552 static void sfq_rehash(struct Qdisc *sch)
553 {
554 struct sfq_sched_data *q = qdisc_priv(sch);
555 struct sk_buff *skb;
556 int i;
557 struct sfq_slot *slot;
558 struct sk_buff_head list;
559 int dropped = 0;
560
561 __skb_queue_head_init(&list);
562
563 for (i = 0; i < q->maxflows; i++) {
564 slot = &q->slots[i];
565 if (!slot->qlen)
566 continue;
567 while (slot->qlen) {
568 skb = slot_dequeue_head(slot);
569 sfq_dec(q, i);
570 __skb_queue_tail(&list, skb);
571 }
572 slot->backlog = 0;
573 red_set_vars(&slot->vars);
574 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
575 }
576 q->tail = NULL;
577
578 while ((skb = __skb_dequeue(&list)) != NULL) {
579 unsigned int hash = sfq_hash(q, skb);
580 sfq_index x = q->ht[hash];
581
582 slot = &q->slots[x];
583 if (x == SFQ_EMPTY_SLOT) {
584 x = q->dep[0].next; /* get a free slot */
585 if (x >= SFQ_MAX_FLOWS) {
586 drop: sch->qstats.backlog -= qdisc_pkt_len(skb);
587 kfree_skb(skb);
588 dropped++;
589 continue;
590 }
591 q->ht[hash] = x;
592 slot = &q->slots[x];
593 slot->hash = hash;
594 }
595 if (slot->qlen >= q->maxdepth)
596 goto drop;
597 slot_queue_add(slot, skb);
598 if (q->red_parms)
599 slot->vars.qavg = red_calc_qavg(q->red_parms,
600 &slot->vars,
601 slot->backlog);
602 slot->backlog += qdisc_pkt_len(skb);
603 sfq_inc(q, x);
604 if (slot->qlen == 1) { /* The flow is new */
605 if (q->tail == NULL) { /* It is the first flow */
606 slot->next = x;
607 } else {
608 slot->next = q->tail->next;
609 q->tail->next = x;
610 }
611 q->tail = slot;
612 slot->allot = q->scaled_quantum;
613 }
614 }
615 sch->q.qlen -= dropped;
616 qdisc_tree_decrease_qlen(sch, dropped);
617 }
618
619 static void sfq_perturbation(unsigned long arg)
620 {
621 struct Qdisc *sch = (struct Qdisc *)arg;
622 struct sfq_sched_data *q = qdisc_priv(sch);
623 spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
624
625 spin_lock(root_lock);
626 q->perturbation = net_random();
627 if (!q->filter_list && q->tail)
628 sfq_rehash(sch);
629 spin_unlock(root_lock);
630
631 if (q->perturb_period)
632 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
633 }
634
635 static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
636 {
637 struct sfq_sched_data *q = qdisc_priv(sch);
638 struct tc_sfq_qopt *ctl = nla_data(opt);
639 struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
640 unsigned int qlen;
641 struct red_parms *p = NULL;
642
643 if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
644 return -EINVAL;
645 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
646 ctl_v1 = nla_data(opt);
647 if (ctl->divisor &&
648 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
649 return -EINVAL;
650 if (ctl_v1 && ctl_v1->qth_min) {
651 p = kmalloc(sizeof(*p), GFP_KERNEL);
652 if (!p)
653 return -ENOMEM;
654 }
655 sch_tree_lock(sch);
656 if (ctl->quantum) {
657 q->quantum = ctl->quantum;
658 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
659 }
660 q->perturb_period = ctl->perturb_period * HZ;
661 if (ctl->flows)
662 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
663 if (ctl->divisor) {
664 q->divisor = ctl->divisor;
665 q->maxflows = min_t(u32, q->maxflows, q->divisor);
666 }
667 if (ctl_v1) {
668 if (ctl_v1->depth)
669 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
670 if (p) {
671 swap(q->red_parms, p);
672 red_set_parms(q->red_parms,
673 ctl_v1->qth_min, ctl_v1->qth_max,
674 ctl_v1->Wlog,
675 ctl_v1->Plog, ctl_v1->Scell_log,
676 NULL,
677 ctl_v1->max_P);
678 }
679 q->flags = ctl_v1->flags;
680 q->headdrop = ctl_v1->headdrop;
681 }
682 if (ctl->limit) {
683 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
684 q->maxflows = min_t(u32, q->maxflows, q->limit);
685 }
686
687 qlen = sch->q.qlen;
688 while (sch->q.qlen > q->limit)
689 sfq_drop(sch);
690 qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
691
692 del_timer(&q->perturb_timer);
693 if (q->perturb_period) {
694 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
695 q->perturbation = net_random();
696 }
697 sch_tree_unlock(sch);
698 kfree(p);
699 return 0;
700 }
701
702 static void *sfq_alloc(size_t sz)
703 {
704 void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN);
705
706 if (!ptr)
707 ptr = vmalloc(sz);
708 return ptr;
709 }
710
711 static void sfq_free(void *addr)
712 {
713 if (addr) {
714 if (is_vmalloc_addr(addr))
715 vfree(addr);
716 else
717 kfree(addr);
718 }
719 }
720
721 static void sfq_destroy(struct Qdisc *sch)
722 {
723 struct sfq_sched_data *q = qdisc_priv(sch);
724
725 tcf_destroy_chain(&q->filter_list);
726 q->perturb_period = 0;
727 del_timer_sync(&q->perturb_timer);
728 sfq_free(q->ht);
729 sfq_free(q->slots);
730 kfree(q->red_parms);
731 }
732
733 static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
734 {
735 struct sfq_sched_data *q = qdisc_priv(sch);
736 int i;
737
738 q->perturb_timer.function = sfq_perturbation;
739 q->perturb_timer.data = (unsigned long)sch;
740 init_timer_deferrable(&q->perturb_timer);
741
742 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
743 q->dep[i].next = i + SFQ_MAX_FLOWS;
744 q->dep[i].prev = i + SFQ_MAX_FLOWS;
745 }
746
747 q->limit = SFQ_MAX_DEPTH;
748 q->maxdepth = SFQ_MAX_DEPTH;
749 q->cur_depth = 0;
750 q->tail = NULL;
751 q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
752 q->maxflows = SFQ_DEFAULT_FLOWS;
753 q->quantum = psched_mtu(qdisc_dev(sch));
754 q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
755 q->perturb_period = 0;
756 q->perturbation = net_random();
757
758 if (opt) {
759 int err = sfq_change(sch, opt);
760 if (err)
761 return err;
762 }
763
764 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
765 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
766 if (!q->ht || !q->slots) {
767 sfq_destroy(sch);
768 return -ENOMEM;
769 }
770 for (i = 0; i < q->divisor; i++)
771 q->ht[i] = SFQ_EMPTY_SLOT;
772
773 for (i = 0; i < q->maxflows; i++) {
774 slot_queue_init(&q->slots[i]);
775 sfq_link(q, i);
776 }
777 if (q->limit >= 1)
778 sch->flags |= TCQ_F_CAN_BYPASS;
779 else
780 sch->flags &= ~TCQ_F_CAN_BYPASS;
781 return 0;
782 }
783
784 static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
785 {
786 struct sfq_sched_data *q = qdisc_priv(sch);
787 unsigned char *b = skb_tail_pointer(skb);
788 struct tc_sfq_qopt_v1 opt;
789 struct red_parms *p = q->red_parms;
790
791 memset(&opt, 0, sizeof(opt));
792 opt.v0.quantum = q->quantum;
793 opt.v0.perturb_period = q->perturb_period / HZ;
794 opt.v0.limit = q->limit;
795 opt.v0.divisor = q->divisor;
796 opt.v0.flows = q->maxflows;
797 opt.depth = q->maxdepth;
798 opt.headdrop = q->headdrop;
799
800 if (p) {
801 opt.qth_min = p->qth_min >> p->Wlog;
802 opt.qth_max = p->qth_max >> p->Wlog;
803 opt.Wlog = p->Wlog;
804 opt.Plog = p->Plog;
805 opt.Scell_log = p->Scell_log;
806 opt.max_P = p->max_P;
807 }
808 memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
809 opt.flags = q->flags;
810
811 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
812
813 return skb->len;
814
815 nla_put_failure:
816 nlmsg_trim(skb, b);
817 return -1;
818 }
819
820 static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
821 {
822 return NULL;
823 }
824
825 static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
826 {
827 return 0;
828 }
829
830 static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
831 u32 classid)
832 {
833 /* we cannot bypass queue discipline anymore */
834 sch->flags &= ~TCQ_F_CAN_BYPASS;
835 return 0;
836 }
837
838 static void sfq_put(struct Qdisc *q, unsigned long cl)
839 {
840 }
841
842 static struct tcf_proto **sfq_find_tcf(struct Qdisc *sch, unsigned long cl)
843 {
844 struct sfq_sched_data *q = qdisc_priv(sch);
845
846 if (cl)
847 return NULL;
848 return &q->filter_list;
849 }
850
851 static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
852 struct sk_buff *skb, struct tcmsg *tcm)
853 {
854 tcm->tcm_handle |= TC_H_MIN(cl);
855 return 0;
856 }
857
858 static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
859 struct gnet_dump *d)
860 {
861 struct sfq_sched_data *q = qdisc_priv(sch);
862 sfq_index idx = q->ht[cl - 1];
863 struct gnet_stats_queue qs = { 0 };
864 struct tc_sfq_xstats xstats = { 0 };
865
866 if (idx != SFQ_EMPTY_SLOT) {
867 const struct sfq_slot *slot = &q->slots[idx];
868
869 xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
870 qs.qlen = slot->qlen;
871 qs.backlog = slot->backlog;
872 }
873 if (gnet_stats_copy_queue(d, &qs) < 0)
874 return -1;
875 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
876 }
877
878 static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
879 {
880 struct sfq_sched_data *q = qdisc_priv(sch);
881 unsigned int i;
882
883 if (arg->stop)
884 return;
885
886 for (i = 0; i < q->divisor; i++) {
887 if (q->ht[i] == SFQ_EMPTY_SLOT ||
888 arg->count < arg->skip) {
889 arg->count++;
890 continue;
891 }
892 if (arg->fn(sch, i + 1, arg) < 0) {
893 arg->stop = 1;
894 break;
895 }
896 arg->count++;
897 }
898 }
899
900 static const struct Qdisc_class_ops sfq_class_ops = {
901 .leaf = sfq_leaf,
902 .get = sfq_get,
903 .put = sfq_put,
904 .tcf_chain = sfq_find_tcf,
905 .bind_tcf = sfq_bind,
906 .unbind_tcf = sfq_put,
907 .dump = sfq_dump_class,
908 .dump_stats = sfq_dump_class_stats,
909 .walk = sfq_walk,
910 };
911
912 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
913 .cl_ops = &sfq_class_ops,
914 .id = "sfq",
915 .priv_size = sizeof(struct sfq_sched_data),
916 .enqueue = sfq_enqueue,
917 .dequeue = sfq_dequeue,
918 .peek = qdisc_peek_dequeued,
919 .drop = sfq_drop,
920 .init = sfq_init,
921 .reset = sfq_reset,
922 .destroy = sfq_destroy,
923 .change = NULL,
924 .dump = sfq_dump,
925 .owner = THIS_MODULE,
926 };
927
928 static int __init sfq_module_init(void)
929 {
930 return register_qdisc(&sfq_qdisc_ops);
931 }
932 static void __exit sfq_module_exit(void)
933 {
934 unregister_qdisc(&sfq_qdisc_ops);
935 }
936 module_init(sfq_module_init)
937 module_exit(sfq_module_exit)
938 MODULE_LICENSE("GPL");
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