?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge tag 'rproc-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc...
[linux.git] / net / sched / sch_sfq.c
blob65d5b59da58303718255c4e2bd61fc34728a7d68
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/sch_sfq.c Stochastic Fairness Queueing discipline.
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 */
7
8 #include <linux/module.h>
9 #include <linux/types.h>
10 #include <linux/kernel.h>
11 #include <linux/jiffies.h>
12 #include <linux/string.h>
13 #include <linux/in.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/skbuff.h>
17 #include <linux/siphash.h>
18 #include <linux/slab.h>
19 #include <linux/vmalloc.h>
20 #include <net/netlink.h>
21 #include <net/pkt_sched.h>
22 #include <net/pkt_cls.h>
23 #include <net/red.h>
24
25
26 /* Stochastic Fairness Queuing algorithm.
27 =======================================
28
29 Source:
30 Paul E. McKenney "Stochastic Fairness Queuing",
31 IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
32
33 Paul E. McKenney "Stochastic Fairness Queuing",
34 "Interworking: Research and Experience", v.2, 1991, p.113-131.
35
36
37 See also:
38 M. Shreedhar and George Varghese "Efficient Fair
39 Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
40
41
42 This is not the thing that is usually called (W)FQ nowadays.
43 It does not use any timestamp mechanism, but instead
44 processes queues in round-robin order.
45
46 ADVANTAGE:
47
48 - It is very cheap. Both CPU and memory requirements are minimal.
49
50 DRAWBACKS:
51
52 - "Stochastic" -> It is not 100% fair.
53 When hash collisions occur, several flows are considered as one.
54
55 - "Round-robin" -> It introduces larger delays than virtual clock
56 based schemes, and should not be used for isolating interactive
57 traffic from non-interactive. It means, that this scheduler
58 should be used as leaf of CBQ or P3, which put interactive traffic
59 to higher priority band.
60
61 We still need true WFQ for top level CSZ, but using WFQ
62 for the best effort traffic is absolutely pointless:
63 SFQ is superior for this purpose.
64
65 IMPLEMENTATION:
66 This implementation limits :
67 - maximal queue length per flow to 127 packets.
68 - max mtu to 2^18-1;
69 - max 65408 flows,
70 - number of hash buckets to 65536.
71
72 It is easy to increase these values, but not in flight. */
73
74 #define SFQ_MAX_DEPTH 127 /* max number of packets per flow */
75 #define SFQ_DEFAULT_FLOWS 128
76 #define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
77 #define SFQ_EMPTY_SLOT 0xffff
78 #define SFQ_DEFAULT_HASH_DIVISOR 1024
79
80 /* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
81 typedef u16 sfq_index;
82
83 /*
84 * We dont use pointers to save space.
85 * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
86 * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
87 * are 'pointers' to dep[] array
88 */
89 struct sfq_head {
90 sfq_index next;
91 sfq_index prev;
92 };
93
94 struct sfq_slot {
95 struct sk_buff *skblist_next;
96 struct sk_buff *skblist_prev;
97 sfq_index qlen; /* number of skbs in skblist */
98 sfq_index next; /* next slot in sfq RR chain */
99 struct sfq_head dep; /* anchor in dep[] chains */
100 unsigned short hash; /* hash value (index in ht[]) */
101 int allot; /* credit for this slot */
102
103 unsigned int backlog;
104 struct red_vars vars;
105 };
106
107 struct sfq_sched_data {
108 /* frequently used fields */
109 int limit; /* limit of total number of packets in this qdisc */
110 unsigned int divisor; /* number of slots in hash table */
111 u8 headdrop;
112 u8 maxdepth; /* limit of packets per flow */
113
114 siphash_key_t perturbation;
115 u8 cur_depth; /* depth of longest slot */
116 u8 flags;
117 struct tcf_proto __rcu *filter_list;
118 struct tcf_block *block;
119 sfq_index *ht; /* Hash table ('divisor' slots) */
120 struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
121
122 struct red_parms *red_parms;
123 struct tc_sfqred_stats stats;
124 struct sfq_slot *tail; /* current slot in round */
125
126 struct sfq_head dep[SFQ_MAX_DEPTH + 1];
127 /* Linked lists of slots, indexed by depth
128 * dep[0] : list of unused flows
129 * dep[1] : list of flows with 1 packet
130 * dep[X] : list of flows with X packets
131 */
132
133 unsigned int maxflows; /* number of flows in flows array */
134 int perturb_period;
135 unsigned int quantum; /* Allotment per round: MUST BE >= MTU */
136 struct timer_list perturb_timer;
137 struct Qdisc *sch;
138 };
139
140 /*
141 * sfq_head are either in a sfq_slot or in dep[] array
142 */
143 static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
144 {
145 if (val < SFQ_MAX_FLOWS)
146 return &q->slots[val].dep;
147 return &q->dep[val - SFQ_MAX_FLOWS];
148 }
149
150 static unsigned int sfq_hash(const struct sfq_sched_data *q,
151 const struct sk_buff *skb)
152 {
153 return skb_get_hash_perturb(skb, &q->perturbation) & (q->divisor - 1);
154 }
155
156 static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
157 int *qerr)
158 {
159 struct sfq_sched_data *q = qdisc_priv(sch);
160 struct tcf_result res;
161 struct tcf_proto *fl;
162 int result;
163
164 if (TC_H_MAJ(skb->priority) == sch->handle &&
165 TC_H_MIN(skb->priority) > 0 &&
166 TC_H_MIN(skb->priority) <= q->divisor)
167 return TC_H_MIN(skb->priority);
168
169 fl = rcu_dereference_bh(q->filter_list);
170 if (!fl)
171 return sfq_hash(q, skb) + 1;
172
173 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
174 result = tcf_classify(skb, NULL, fl, &res, false);
175 if (result >= 0) {
176 #ifdef CONFIG_NET_CLS_ACT
177 switch (result) {
178 case TC_ACT_STOLEN:
179 case TC_ACT_QUEUED:
180 case TC_ACT_TRAP:
181 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
182 fallthrough;
183 case TC_ACT_SHOT:
184 return 0;
185 }
186 #endif
187 if (TC_H_MIN(res.classid) <= q->divisor)
188 return TC_H_MIN(res.classid);
189 }
190 return 0;
191 }
192
193 /*
194 * x : slot number [0 .. SFQ_MAX_FLOWS - 1]
195 */
196 static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
197 {
198 sfq_index p, n;
199 struct sfq_slot *slot = &q->slots[x];
200 int qlen = slot->qlen;
201
202 p = qlen + SFQ_MAX_FLOWS;
203 n = q->dep[qlen].next;
204
205 slot->dep.next = n;
206 slot->dep.prev = p;
207
208 q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */
209 sfq_dep_head(q, n)->prev = x;
210 }
211
212 #define sfq_unlink(q, x, n, p) \
213 do { \
214 n = q->slots[x].dep.next; \
215 p = q->slots[x].dep.prev; \
216 sfq_dep_head(q, p)->next = n; \
217 sfq_dep_head(q, n)->prev = p; \
218 } while (0)
219
220
221 static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
222 {
223 sfq_index p, n;
224 int d;
225
226 sfq_unlink(q, x, n, p);
227
228 d = q->slots[x].qlen--;
229 if (n == p && q->cur_depth == d)
230 q->cur_depth--;
231 sfq_link(q, x);
232 }
233
234 static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
235 {
236 sfq_index p, n;
237 int d;
238
239 sfq_unlink(q, x, n, p);
240
241 d = ++q->slots[x].qlen;
242 if (q->cur_depth < d)
243 q->cur_depth = d;
244 sfq_link(q, x);
245 }
246
247 /* helper functions : might be changed when/if skb use a standard list_head */
248
249 /* remove one skb from tail of slot queue */
250 static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
251 {
252 struct sk_buff *skb = slot->skblist_prev;
253
254 slot->skblist_prev = skb->prev;
255 skb->prev->next = (struct sk_buff *)slot;
256 skb->next = skb->prev = NULL;
257 return skb;
258 }
259
260 /* remove one skb from head of slot queue */
261 static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
262 {
263 struct sk_buff *skb = slot->skblist_next;
264
265 slot->skblist_next = skb->next;
266 skb->next->prev = (struct sk_buff *)slot;
267 skb->next = skb->prev = NULL;
268 return skb;
269 }
270
271 static inline void slot_queue_init(struct sfq_slot *slot)
272 {
273 memset(slot, 0, sizeof(*slot));
274 slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
275 }
276
277 /* add skb to slot queue (tail add) */
278 static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
279 {
280 skb->prev = slot->skblist_prev;
281 skb->next = (struct sk_buff *)slot;
282 slot->skblist_prev->next = skb;
283 slot->skblist_prev = skb;
284 }
285
286 static unsigned int sfq_drop(struct Qdisc *sch, struct sk_buff **to_free)
287 {
288 struct sfq_sched_data *q = qdisc_priv(sch);
289 sfq_index x, d = q->cur_depth;
290 struct sk_buff *skb;
291 unsigned int len;
292 struct sfq_slot *slot;
293
294 /* Queue is full! Find the longest slot and drop tail packet from it */
295 if (d > 1) {
296 x = q->dep[d].next;
297 slot = &q->slots[x];
298 drop:
299 skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
300 len = qdisc_pkt_len(skb);
301 slot->backlog -= len;
302 sfq_dec(q, x);
303 sch->q.qlen--;
304 qdisc_qstats_backlog_dec(sch, skb);
305 qdisc_drop(skb, sch, to_free);
306 return len;
307 }
308
309 if (d == 1) {
310 /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
311 x = q->tail->next;
312 slot = &q->slots[x];
313 q->tail->next = slot->next;
314 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
315 goto drop;
316 }
317
318 return 0;
319 }
320
321 /* Is ECN parameter configured */
322 static int sfq_prob_mark(const struct sfq_sched_data *q)
323 {
324 return q->flags & TC_RED_ECN;
325 }
326
327 /* Should packets over max threshold just be marked */
328 static int sfq_hard_mark(const struct sfq_sched_data *q)
329 {
330 return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
331 }
332
333 static int sfq_headdrop(const struct sfq_sched_data *q)
334 {
335 return q->headdrop;
336 }
337
338 static int
339 sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
340 {
341 struct sfq_sched_data *q = qdisc_priv(sch);
342 unsigned int hash, dropped;
343 sfq_index x, qlen;
344 struct sfq_slot *slot;
345 int ret;
346 struct sk_buff *head;
347 int delta;
348
349 hash = sfq_classify(skb, sch, &ret);
350 if (hash == 0) {
351 if (ret & __NET_XMIT_BYPASS)
352 qdisc_qstats_drop(sch);
353 __qdisc_drop(skb, to_free);
354 return ret;
355 }
356 hash--;
357
358 x = q->ht[hash];
359 slot = &q->slots[x];
360 if (x == SFQ_EMPTY_SLOT) {
361 x = q->dep[0].next; /* get a free slot */
362 if (x >= SFQ_MAX_FLOWS)
363 return qdisc_drop(skb, sch, to_free);
364 q->ht[hash] = x;
365 slot = &q->slots[x];
366 slot->hash = hash;
367 slot->backlog = 0; /* should already be 0 anyway... */
368 red_set_vars(&slot->vars);
369 goto enqueue;
370 }
371 if (q->red_parms) {
372 slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
373 &slot->vars,
374 slot->backlog);
375 switch (red_action(q->red_parms,
376 &slot->vars,
377 slot->vars.qavg)) {
378 case RED_DONT_MARK:
379 break;
380
381 case RED_PROB_MARK:
382 qdisc_qstats_overlimit(sch);
383 if (sfq_prob_mark(q)) {
384 /* We know we have at least one packet in queue */
385 if (sfq_headdrop(q) &&
386 INET_ECN_set_ce(slot->skblist_next)) {
387 q->stats.prob_mark_head++;
388 break;
389 }
390 if (INET_ECN_set_ce(skb)) {
391 q->stats.prob_mark++;
392 break;
393 }
394 }
395 q->stats.prob_drop++;
396 goto congestion_drop;
397
398 case RED_HARD_MARK:
399 qdisc_qstats_overlimit(sch);
400 if (sfq_hard_mark(q)) {
401 /* We know we have at least one packet in queue */
402 if (sfq_headdrop(q) &&
403 INET_ECN_set_ce(slot->skblist_next)) {
404 q->stats.forced_mark_head++;
405 break;
406 }
407 if (INET_ECN_set_ce(skb)) {
408 q->stats.forced_mark++;
409 break;
410 }
411 }
412 q->stats.forced_drop++;
413 goto congestion_drop;
414 }
415 }
416
417 if (slot->qlen >= q->maxdepth) {
418 congestion_drop:
419 if (!sfq_headdrop(q))
420 return qdisc_drop(skb, sch, to_free);
421
422 /* We know we have at least one packet in queue */
423 head = slot_dequeue_head(slot);
424 delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
425 sch->qstats.backlog -= delta;
426 slot->backlog -= delta;
427 qdisc_drop(head, sch, to_free);
428
429 slot_queue_add(slot, skb);
430 qdisc_tree_reduce_backlog(sch, 0, delta);
431 return NET_XMIT_CN;
432 }
433
434 enqueue:
435 qdisc_qstats_backlog_inc(sch, skb);
436 slot->backlog += qdisc_pkt_len(skb);
437 slot_queue_add(slot, skb);
438 sfq_inc(q, x);
439 if (slot->qlen == 1) { /* The flow is new */
440 if (q->tail == NULL) { /* It is the first flow */
441 slot->next = x;
442 } else {
443 slot->next = q->tail->next;
444 q->tail->next = x;
445 }
446 /* We put this flow at the end of our flow list.
447 * This might sound unfair for a new flow to wait after old ones,
448 * but we could endup servicing new flows only, and freeze old ones.
449 */
450 q->tail = slot;
451 /* We could use a bigger initial quantum for new flows */
452 slot->allot = q->quantum;
453 }
454 if (++sch->q.qlen <= q->limit)
455 return NET_XMIT_SUCCESS;
456
457 qlen = slot->qlen;
458 dropped = sfq_drop(sch, to_free);
459 /* Return Congestion Notification only if we dropped a packet
460 * from this flow.
461 */
462 if (qlen != slot->qlen) {
463 qdisc_tree_reduce_backlog(sch, 0, dropped - qdisc_pkt_len(skb));
464 return NET_XMIT_CN;
465 }
466
467 /* As we dropped a packet, better let upper stack know this */
468 qdisc_tree_reduce_backlog(sch, 1, dropped);
469 return NET_XMIT_SUCCESS;
470 }
471
472 static struct sk_buff *
473 sfq_dequeue(struct Qdisc *sch)
474 {
475 struct sfq_sched_data *q = qdisc_priv(sch);
476 struct sk_buff *skb;
477 sfq_index a, next_a;
478 struct sfq_slot *slot;
479
480 /* No active slots */
481 if (q->tail == NULL)
482 return NULL;
483
484 next_slot:
485 a = q->tail->next;
486 slot = &q->slots[a];
487 if (slot->allot <= 0) {
488 q->tail = slot;
489 slot->allot += q->quantum;
490 goto next_slot;
491 }
492 skb = slot_dequeue_head(slot);
493 sfq_dec(q, a);
494 qdisc_bstats_update(sch, skb);
495 sch->q.qlen--;
496 qdisc_qstats_backlog_dec(sch, skb);
497 slot->backlog -= qdisc_pkt_len(skb);
498 /* Is the slot empty? */
499 if (slot->qlen == 0) {
500 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
501 next_a = slot->next;
502 if (a == next_a) {
503 q->tail = NULL; /* no more active slots */
504 return skb;
505 }
506 q->tail->next = next_a;
507 } else {
508 slot->allot -= qdisc_pkt_len(skb);
509 }
510 return skb;
511 }
512
513 static void
514 sfq_reset(struct Qdisc *sch)
515 {
516 struct sk_buff *skb;
517
518 while ((skb = sfq_dequeue(sch)) != NULL)
519 rtnl_kfree_skbs(skb, skb);
520 }
521
522 /*
523 * When q->perturbation is changed, we rehash all queued skbs
524 * to avoid OOO (Out Of Order) effects.
525 * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
526 * counters.
527 */
528 static void sfq_rehash(struct Qdisc *sch)
529 {
530 struct sfq_sched_data *q = qdisc_priv(sch);
531 struct sk_buff *skb;
532 int i;
533 struct sfq_slot *slot;
534 struct sk_buff_head list;
535 int dropped = 0;
536 unsigned int drop_len = 0;
537
538 __skb_queue_head_init(&list);
539
540 for (i = 0; i < q->maxflows; i++) {
541 slot = &q->slots[i];
542 if (!slot->qlen)
543 continue;
544 while (slot->qlen) {
545 skb = slot_dequeue_head(slot);
546 sfq_dec(q, i);
547 __skb_queue_tail(&list, skb);
548 }
549 slot->backlog = 0;
550 red_set_vars(&slot->vars);
551 q->ht[slot->hash] = SFQ_EMPTY_SLOT;
552 }
553 q->tail = NULL;
554
555 while ((skb = __skb_dequeue(&list)) != NULL) {
556 unsigned int hash = sfq_hash(q, skb);
557 sfq_index x = q->ht[hash];
558
559 slot = &q->slots[x];
560 if (x == SFQ_EMPTY_SLOT) {
561 x = q->dep[0].next; /* get a free slot */
562 if (x >= SFQ_MAX_FLOWS) {
563 drop:
564 qdisc_qstats_backlog_dec(sch, skb);
565 drop_len += qdisc_pkt_len(skb);
566 kfree_skb(skb);
567 dropped++;
568 continue;
569 }
570 q->ht[hash] = x;
571 slot = &q->slots[x];
572 slot->hash = hash;
573 }
574 if (slot->qlen >= q->maxdepth)
575 goto drop;
576 slot_queue_add(slot, skb);
577 if (q->red_parms)
578 slot->vars.qavg = red_calc_qavg(q->red_parms,
579 &slot->vars,
580 slot->backlog);
581 slot->backlog += qdisc_pkt_len(skb);
582 sfq_inc(q, x);
583 if (slot->qlen == 1) { /* The flow is new */
584 if (q->tail == NULL) { /* It is the first flow */
585 slot->next = x;
586 } else {
587 slot->next = q->tail->next;
588 q->tail->next = x;
589 }
590 q->tail = slot;
591 slot->allot = q->quantum;
592 }
593 }
594 sch->q.qlen -= dropped;
595 qdisc_tree_reduce_backlog(sch, dropped, drop_len);
596 }
597
598 static void sfq_perturbation(struct timer_list *t)
599 {
600 struct sfq_sched_data *q = from_timer(q, t, perturb_timer);
601 struct Qdisc *sch = q->sch;
602 spinlock_t *root_lock;
603 siphash_key_t nkey;
604 int period;
605
606 get_random_bytes(&nkey, sizeof(nkey));
607 rcu_read_lock();
608 root_lock = qdisc_lock(qdisc_root_sleeping(sch));
609 spin_lock(root_lock);
610 q->perturbation = nkey;
611 if (!q->filter_list && q->tail)
612 sfq_rehash(sch);
613 spin_unlock(root_lock);
614
615 /* q->perturb_period can change under us from
616 * sfq_change() and sfq_destroy().
617 */
618 period = READ_ONCE(q->perturb_period);
619 if (period)
620 mod_timer(&q->perturb_timer, jiffies + period);
621 rcu_read_unlock();
622 }
623
624 static int sfq_change(struct Qdisc *sch, struct nlattr *opt,
625 struct netlink_ext_ack *extack)
626 {
627 struct sfq_sched_data *q = qdisc_priv(sch);
628 struct tc_sfq_qopt *ctl = nla_data(opt);
629 struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
630 unsigned int qlen, dropped = 0;
631 struct red_parms *p = NULL;
632 struct sk_buff *to_free = NULL;
633 struct sk_buff *tail = NULL;
634
635 if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
636 return -EINVAL;
637 if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
638 ctl_v1 = nla_data(opt);
639 if (ctl->divisor &&
640 (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
641 return -EINVAL;
642
643 if ((int)ctl->quantum < 0) {
644 NL_SET_ERR_MSG_MOD(extack, "invalid quantum");
645 return -EINVAL;
646 }
647 if (ctl_v1 && !red_check_params(ctl_v1->qth_min, ctl_v1->qth_max,
648 ctl_v1->Wlog, ctl_v1->Scell_log, NULL))
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 if (ctl->limit == 1) {
656 NL_SET_ERR_MSG_MOD(extack, "invalid limit");
657 return -EINVAL;
658 }
659 sch_tree_lock(sch);
660 if (ctl->quantum)
661 q->quantum = ctl->quantum;
662 WRITE_ONCE(q->perturb_period, ctl->perturb_period * HZ);
663 if (ctl->flows)
664 q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
665 if (ctl->divisor) {
666 q->divisor = ctl->divisor;
667 q->maxflows = min_t(u32, q->maxflows, q->divisor);
668 }
669 if (ctl_v1) {
670 if (ctl_v1->depth)
671 q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
672 if (p) {
673 swap(q->red_parms, p);
674 red_set_parms(q->red_parms,
675 ctl_v1->qth_min, ctl_v1->qth_max,
676 ctl_v1->Wlog,
677 ctl_v1->Plog, ctl_v1->Scell_log,
678 NULL,
679 ctl_v1->max_P);
680 }
681 q->flags = ctl_v1->flags;
682 q->headdrop = ctl_v1->headdrop;
683 }
684 if (ctl->limit) {
685 q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
686 q->maxflows = min_t(u32, q->maxflows, q->limit);
687 }
688
689 qlen = sch->q.qlen;
690 while (sch->q.qlen > q->limit) {
691 dropped += sfq_drop(sch, &to_free);
692 if (!tail)
693 tail = to_free;
694 }
695
696 rtnl_kfree_skbs(to_free, tail);
697 qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);
698
699 del_timer(&q->perturb_timer);
700 if (q->perturb_period) {
701 mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
702 get_random_bytes(&q->perturbation, sizeof(q->perturbation));
703 }
704 sch_tree_unlock(sch);
705 kfree(p);
706 return 0;
707 }
708
709 static void *sfq_alloc(size_t sz)
710 {
711 return kvmalloc(sz, GFP_KERNEL);
712 }
713
714 static void sfq_free(void *addr)
715 {
716 kvfree(addr);
717 }
718
719 static void sfq_destroy(struct Qdisc *sch)
720 {
721 struct sfq_sched_data *q = qdisc_priv(sch);
722
723 tcf_block_put(q->block);
724 WRITE_ONCE(q->perturb_period, 0);
725 del_timer_sync(&q->perturb_timer);
726 sfq_free(q->ht);
727 sfq_free(q->slots);
728 kfree(q->red_parms);
729 }
730
731 static int sfq_init(struct Qdisc *sch, struct nlattr *opt,
732 struct netlink_ext_ack *extack)
733 {
734 struct sfq_sched_data *q = qdisc_priv(sch);
735 int i;
736 int err;
737
738 q->sch = sch;
739 timer_setup(&q->perturb_timer, sfq_perturbation, TIMER_DEFERRABLE);
740
741 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
742 if (err)
743 return err;
744
745 for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
746 q->dep[i].next = i + SFQ_MAX_FLOWS;
747 q->dep[i].prev = i + SFQ_MAX_FLOWS;
748 }
749
750 q->limit = SFQ_MAX_DEPTH;
751 q->maxdepth = SFQ_MAX_DEPTH;
752 q->cur_depth = 0;
753 q->tail = NULL;
754 q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
755 q->maxflows = SFQ_DEFAULT_FLOWS;
756 q->quantum = psched_mtu(qdisc_dev(sch));
757 q->perturb_period = 0;
758 get_random_bytes(&q->perturbation, sizeof(q->perturbation));
759
760 if (opt) {
761 int err = sfq_change(sch, opt, extack);
762 if (err)
763 return err;
764 }
765
766 q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
767 q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
768 if (!q->ht || !q->slots) {
769 /* Note: sfq_destroy() will be called by our caller */
770 return -ENOMEM;
771 }
772
773 for (i = 0; i < q->divisor; i++)
774 q->ht[i] = SFQ_EMPTY_SLOT;
775
776 for (i = 0; i < q->maxflows; i++) {
777 slot_queue_init(&q->slots[i]);
778 sfq_link(q, i);
779 }
780 if (q->limit >= 1)
781 sch->flags |= TCQ_F_CAN_BYPASS;
782 else
783 sch->flags &= ~TCQ_F_CAN_BYPASS;
784 return 0;
785 }
786
787 static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
788 {
789 struct sfq_sched_data *q = qdisc_priv(sch);
790 unsigned char *b = skb_tail_pointer(skb);
791 struct tc_sfq_qopt_v1 opt;
792 struct red_parms *p = q->red_parms;
793
794 memset(&opt, 0, sizeof(opt));
795 opt.v0.quantum = q->quantum;
796 opt.v0.perturb_period = q->perturb_period / HZ;
797 opt.v0.limit = q->limit;
798 opt.v0.divisor = q->divisor;
799 opt.v0.flows = q->maxflows;
800 opt.depth = q->maxdepth;
801 opt.headdrop = q->headdrop;
802
803 if (p) {
804 opt.qth_min = p->qth_min >> p->Wlog;
805 opt.qth_max = p->qth_max >> p->Wlog;
806 opt.Wlog = p->Wlog;
807 opt.Plog = p->Plog;
808 opt.Scell_log = p->Scell_log;
809 opt.max_P = p->max_P;
810 }
811 memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
812 opt.flags = q->flags;
813
814 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
815 goto nla_put_failure;
816
817 return skb->len;
818
819 nla_put_failure:
820 nlmsg_trim(skb, b);
821 return -1;
822 }
823
824 static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
825 {
826 return NULL;
827 }
828
829 static unsigned long sfq_find(struct Qdisc *sch, u32 classid)
830 {
831 return 0;
832 }
833
834 static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
835 u32 classid)
836 {
837 return 0;
838 }
839
840 static void sfq_unbind(struct Qdisc *q, unsigned long cl)
841 {
842 }
843
844 static struct tcf_block *sfq_tcf_block(struct Qdisc *sch, unsigned long cl,
845 struct netlink_ext_ack *extack)
846 {
847 struct sfq_sched_data *q = qdisc_priv(sch);
848
849 if (cl)
850 return NULL;
851 return q->block;
852 }
853
854 static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
855 struct sk_buff *skb, struct tcmsg *tcm)
856 {
857 tcm->tcm_handle |= TC_H_MIN(cl);
858 return 0;
859 }
860
861 static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
862 struct gnet_dump *d)
863 {
864 struct sfq_sched_data *q = qdisc_priv(sch);
865 sfq_index idx = q->ht[cl - 1];
866 struct gnet_stats_queue qs = { 0 };
867 struct tc_sfq_xstats xstats = { 0 };
868
869 if (idx != SFQ_EMPTY_SLOT) {
870 const struct sfq_slot *slot = &q->slots[idx];
871
872 xstats.allot = slot->allot;
873 qs.qlen = slot->qlen;
874 qs.backlog = slot->backlog;
875 }
876 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
877 return -1;
878 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
879 }
880
881 static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
882 {
883 struct sfq_sched_data *q = qdisc_priv(sch);
884 unsigned int i;
885
886 if (arg->stop)
887 return;
888
889 for (i = 0; i < q->divisor; i++) {
890 if (q->ht[i] == SFQ_EMPTY_SLOT) {
891 arg->count++;
892 continue;
893 }
894 if (!tc_qdisc_stats_dump(sch, i + 1, arg))
895 break;
896 }
897 }
898
899 static const struct Qdisc_class_ops sfq_class_ops = {
900 .leaf = sfq_leaf,
901 .find = sfq_find,
902 .tcf_block = sfq_tcf_block,
903 .bind_tcf = sfq_bind,
904 .unbind_tcf = sfq_unbind,
905 .dump = sfq_dump_class,
906 .dump_stats = sfq_dump_class_stats,
907 .walk = sfq_walk,
908 };
909
910 static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
911 .cl_ops = &sfq_class_ops,
912 .id = "sfq",
913 .priv_size = sizeof(struct sfq_sched_data),
914 .enqueue = sfq_enqueue,
915 .dequeue = sfq_dequeue,
916 .peek = qdisc_peek_dequeued,
917 .init = sfq_init,
918 .reset = sfq_reset,
919 .destroy = sfq_destroy,
920 .change = NULL,
921 .dump = sfq_dump,
922 .owner = THIS_MODULE,
923 };
924 MODULE_ALIAS_NET_SCH("sfq");
925
926 static int __init sfq_module_init(void)
927 {
928 return register_qdisc(&sfq_qdisc_ops);
929 }
930 static void __exit sfq_module_exit(void)
931 {
932 unregister_qdisc(&sfq_qdisc_ops);
933 }
934 module_init(sfq_module_init)
935 module_exit(sfq_module_exit)
936 MODULE_LICENSE("GPL");
937 MODULE_DESCRIPTION("Stochastic Fairness qdisc");
Linux Kernel