net/sched: act_ife: Staticfy find_decode_metaid()
[sfrench/cifs-2.6.git] / net / sched / sch_fq_codel.c
1 /*
2  * Fair Queue CoDel 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  *  Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com>
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/pkt_cls.h>
27 #include <net/codel.h>
28 #include <net/codel_impl.h>
29 #include <net/codel_qdisc.h>
30
31 /*      Fair Queue CoDel.
32  *
33  * Principles :
34  * Packets are classified (internal classifier or external) on flows.
35  * This is a Stochastic model (as we use a hash, several flows
36  *                             might be hashed on same slot)
37  * Each flow has a CoDel managed queue.
38  * Flows are linked onto two (Round Robin) lists,
39  * so that new flows have priority on old ones.
40  *
41  * For a given flow, packets are not reordered (CoDel uses a FIFO)
42  * head drops only.
43  * ECN capability is on by default.
44  * Low memory footprint (64 bytes per flow)
45  */
46
47 struct fq_codel_flow {
48         struct sk_buff    *head;
49         struct sk_buff    *tail;
50         struct list_head  flowchain;
51         int               deficit;
52         u32               dropped; /* number of drops (or ECN marks) on this flow */
53         struct codel_vars cvars;
54 }; /* please try to keep this structure <= 64 bytes */
55
56 struct fq_codel_sched_data {
57         struct tcf_proto __rcu *filter_list; /* optional external classifier */
58         struct fq_codel_flow *flows;    /* Flows table [flows_cnt] */
59         u32             *backlogs;      /* backlog table [flows_cnt] */
60         u32             flows_cnt;      /* number of flows */
61         u32             quantum;        /* psched_mtu(qdisc_dev(sch)); */
62         u32             drop_batch_size;
63         u32             memory_limit;
64         struct codel_params cparams;
65         struct codel_stats cstats;
66         u32             memory_usage;
67         u32             drop_overmemory;
68         u32             drop_overlimit;
69         u32             new_flow_count;
70
71         struct list_head new_flows;     /* list of new flows */
72         struct list_head old_flows;     /* list of old flows */
73 };
74
75 static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q,
76                                   struct sk_buff *skb)
77 {
78         return reciprocal_scale(skb_get_hash(skb), q->flows_cnt);
79 }
80
81 static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
82                                       int *qerr)
83 {
84         struct fq_codel_sched_data *q = qdisc_priv(sch);
85         struct tcf_proto *filter;
86         struct tcf_result res;
87         int result;
88
89         if (TC_H_MAJ(skb->priority) == sch->handle &&
90             TC_H_MIN(skb->priority) > 0 &&
91             TC_H_MIN(skb->priority) <= q->flows_cnt)
92                 return TC_H_MIN(skb->priority);
93
94         filter = rcu_dereference_bh(q->filter_list);
95         if (!filter)
96                 return fq_codel_hash(q, skb) + 1;
97
98         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
99         result = tc_classify(skb, filter, &res, false);
100         if (result >= 0) {
101 #ifdef CONFIG_NET_CLS_ACT
102                 switch (result) {
103                 case TC_ACT_STOLEN:
104                 case TC_ACT_QUEUED:
105                         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
106                 case TC_ACT_SHOT:
107                         return 0;
108                 }
109 #endif
110                 if (TC_H_MIN(res.classid) <= q->flows_cnt)
111                         return TC_H_MIN(res.classid);
112         }
113         return 0;
114 }
115
116 /* helper functions : might be changed when/if skb use a standard list_head */
117
118 /* remove one skb from head of slot queue */
119 static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow)
120 {
121         struct sk_buff *skb = flow->head;
122
123         flow->head = skb->next;
124         skb->next = NULL;
125         return skb;
126 }
127
128 /* add skb to flow queue (tail add) */
129 static inline void flow_queue_add(struct fq_codel_flow *flow,
130                                   struct sk_buff *skb)
131 {
132         if (flow->head == NULL)
133                 flow->head = skb;
134         else
135                 flow->tail->next = skb;
136         flow->tail = skb;
137         skb->next = NULL;
138 }
139
140 static unsigned int fq_codel_drop(struct Qdisc *sch, unsigned int max_packets,
141                                   struct sk_buff **to_free)
142 {
143         struct fq_codel_sched_data *q = qdisc_priv(sch);
144         struct sk_buff *skb;
145         unsigned int maxbacklog = 0, idx = 0, i, len;
146         struct fq_codel_flow *flow;
147         unsigned int threshold;
148         unsigned int mem = 0;
149
150         /* Queue is full! Find the fat flow and drop packet(s) from it.
151          * This might sound expensive, but with 1024 flows, we scan
152          * 4KB of memory, and we dont need to handle a complex tree
153          * in fast path (packet queue/enqueue) with many cache misses.
154          * In stress mode, we'll try to drop 64 packets from the flow,
155          * amortizing this linear lookup to one cache line per drop.
156          */
157         for (i = 0; i < q->flows_cnt; i++) {
158                 if (q->backlogs[i] > maxbacklog) {
159                         maxbacklog = q->backlogs[i];
160                         idx = i;
161                 }
162         }
163
164         /* Our goal is to drop half of this fat flow backlog */
165         threshold = maxbacklog >> 1;
166
167         flow = &q->flows[idx];
168         len = 0;
169         i = 0;
170         do {
171                 skb = dequeue_head(flow);
172                 len += qdisc_pkt_len(skb);
173                 mem += get_codel_cb(skb)->mem_usage;
174                 __qdisc_drop(skb, to_free);
175         } while (++i < max_packets && len < threshold);
176
177         flow->dropped += i;
178         q->backlogs[idx] -= len;
179         q->memory_usage -= mem;
180         sch->qstats.drops += i;
181         sch->qstats.backlog -= len;
182         sch->q.qlen -= i;
183         return idx;
184 }
185
186 static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch,
187                             struct sk_buff **to_free)
188 {
189         struct fq_codel_sched_data *q = qdisc_priv(sch);
190         unsigned int idx, prev_backlog, prev_qlen;
191         struct fq_codel_flow *flow;
192         int uninitialized_var(ret);
193         unsigned int pkt_len;
194         bool memory_limited;
195
196         idx = fq_codel_classify(skb, sch, &ret);
197         if (idx == 0) {
198                 if (ret & __NET_XMIT_BYPASS)
199                         qdisc_qstats_drop(sch);
200                 __qdisc_drop(skb, to_free);
201                 return ret;
202         }
203         idx--;
204
205         codel_set_enqueue_time(skb);
206         flow = &q->flows[idx];
207         flow_queue_add(flow, skb);
208         q->backlogs[idx] += qdisc_pkt_len(skb);
209         qdisc_qstats_backlog_inc(sch, skb);
210
211         if (list_empty(&flow->flowchain)) {
212                 list_add_tail(&flow->flowchain, &q->new_flows);
213                 q->new_flow_count++;
214                 flow->deficit = q->quantum;
215                 flow->dropped = 0;
216         }
217         get_codel_cb(skb)->mem_usage = skb->truesize;
218         q->memory_usage += get_codel_cb(skb)->mem_usage;
219         memory_limited = q->memory_usage > q->memory_limit;
220         if (++sch->q.qlen <= sch->limit && !memory_limited)
221                 return NET_XMIT_SUCCESS;
222
223         prev_backlog = sch->qstats.backlog;
224         prev_qlen = sch->q.qlen;
225
226         /* save this packet length as it might be dropped by fq_codel_drop() */
227         pkt_len = qdisc_pkt_len(skb);
228         /* fq_codel_drop() is quite expensive, as it performs a linear search
229          * in q->backlogs[] to find a fat flow.
230          * So instead of dropping a single packet, drop half of its backlog
231          * with a 64 packets limit to not add a too big cpu spike here.
232          */
233         ret = fq_codel_drop(sch, q->drop_batch_size, to_free);
234
235         prev_qlen -= sch->q.qlen;
236         prev_backlog -= sch->qstats.backlog;
237         q->drop_overlimit += prev_qlen;
238         if (memory_limited)
239                 q->drop_overmemory += prev_qlen;
240
241         /* As we dropped packet(s), better let upper stack know this.
242          * If we dropped a packet for this flow, return NET_XMIT_CN,
243          * but in this case, our parents wont increase their backlogs.
244          */
245         if (ret == idx) {
246                 qdisc_tree_reduce_backlog(sch, prev_qlen - 1,
247                                           prev_backlog - pkt_len);
248                 return NET_XMIT_CN;
249         }
250         qdisc_tree_reduce_backlog(sch, prev_qlen, prev_backlog);
251         return NET_XMIT_SUCCESS;
252 }
253
254 /* This is the specific function called from codel_dequeue()
255  * to dequeue a packet from queue. Note: backlog is handled in
256  * codel, we dont need to reduce it here.
257  */
258 static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx)
259 {
260         struct Qdisc *sch = ctx;
261         struct fq_codel_sched_data *q = qdisc_priv(sch);
262         struct fq_codel_flow *flow;
263         struct sk_buff *skb = NULL;
264
265         flow = container_of(vars, struct fq_codel_flow, cvars);
266         if (flow->head) {
267                 skb = dequeue_head(flow);
268                 q->backlogs[flow - q->flows] -= qdisc_pkt_len(skb);
269                 q->memory_usage -= get_codel_cb(skb)->mem_usage;
270                 sch->q.qlen--;
271                 sch->qstats.backlog -= qdisc_pkt_len(skb);
272         }
273         return skb;
274 }
275
276 static void drop_func(struct sk_buff *skb, void *ctx)
277 {
278         struct Qdisc *sch = ctx;
279
280         kfree_skb(skb);
281         qdisc_qstats_drop(sch);
282 }
283
284 static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
285 {
286         struct fq_codel_sched_data *q = qdisc_priv(sch);
287         struct sk_buff *skb;
288         struct fq_codel_flow *flow;
289         struct list_head *head;
290         u32 prev_drop_count, prev_ecn_mark;
291         unsigned int prev_backlog;
292
293 begin:
294         head = &q->new_flows;
295         if (list_empty(head)) {
296                 head = &q->old_flows;
297                 if (list_empty(head))
298                         return NULL;
299         }
300         flow = list_first_entry(head, struct fq_codel_flow, flowchain);
301
302         if (flow->deficit <= 0) {
303                 flow->deficit += q->quantum;
304                 list_move_tail(&flow->flowchain, &q->old_flows);
305                 goto begin;
306         }
307
308         prev_drop_count = q->cstats.drop_count;
309         prev_ecn_mark = q->cstats.ecn_mark;
310         prev_backlog = sch->qstats.backlog;
311
312         skb = codel_dequeue(sch, &sch->qstats.backlog, &q->cparams,
313                             &flow->cvars, &q->cstats, qdisc_pkt_len,
314                             codel_get_enqueue_time, drop_func, dequeue_func);
315
316         flow->dropped += q->cstats.drop_count - prev_drop_count;
317         flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
318
319         if (!skb) {
320                 /* force a pass through old_flows to prevent starvation */
321                 if ((head == &q->new_flows) && !list_empty(&q->old_flows))
322                         list_move_tail(&flow->flowchain, &q->old_flows);
323                 else
324                         list_del_init(&flow->flowchain);
325                 goto begin;
326         }
327         qdisc_bstats_update(sch, skb);
328         flow->deficit -= qdisc_pkt_len(skb);
329         /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0,
330          * or HTB crashes. Defer it for next round.
331          */
332         if (q->cstats.drop_count && sch->q.qlen) {
333                 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
334                                           q->cstats.drop_len);
335                 q->cstats.drop_count = 0;
336                 q->cstats.drop_len = 0;
337         }
338         return skb;
339 }
340
341 static void fq_codel_flow_purge(struct fq_codel_flow *flow)
342 {
343         rtnl_kfree_skbs(flow->head, flow->tail);
344         flow->head = NULL;
345 }
346
347 static void fq_codel_reset(struct Qdisc *sch)
348 {
349         struct fq_codel_sched_data *q = qdisc_priv(sch);
350         int i;
351
352         INIT_LIST_HEAD(&q->new_flows);
353         INIT_LIST_HEAD(&q->old_flows);
354         for (i = 0; i < q->flows_cnt; i++) {
355                 struct fq_codel_flow *flow = q->flows + i;
356
357                 fq_codel_flow_purge(flow);
358                 INIT_LIST_HEAD(&flow->flowchain);
359                 codel_vars_init(&flow->cvars);
360         }
361         memset(q->backlogs, 0, q->flows_cnt * sizeof(u32));
362         sch->q.qlen = 0;
363         sch->qstats.backlog = 0;
364         q->memory_usage = 0;
365 }
366
367 static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
368         [TCA_FQ_CODEL_TARGET]   = { .type = NLA_U32 },
369         [TCA_FQ_CODEL_LIMIT]    = { .type = NLA_U32 },
370         [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 },
371         [TCA_FQ_CODEL_ECN]      = { .type = NLA_U32 },
372         [TCA_FQ_CODEL_FLOWS]    = { .type = NLA_U32 },
373         [TCA_FQ_CODEL_QUANTUM]  = { .type = NLA_U32 },
374         [TCA_FQ_CODEL_CE_THRESHOLD] = { .type = NLA_U32 },
375         [TCA_FQ_CODEL_DROP_BATCH_SIZE] = { .type = NLA_U32 },
376         [TCA_FQ_CODEL_MEMORY_LIMIT] = { .type = NLA_U32 },
377 };
378
379 static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt)
380 {
381         struct fq_codel_sched_data *q = qdisc_priv(sch);
382         struct nlattr *tb[TCA_FQ_CODEL_MAX + 1];
383         int err;
384
385         if (!opt)
386                 return -EINVAL;
387
388         err = nla_parse_nested(tb, TCA_FQ_CODEL_MAX, opt, fq_codel_policy);
389         if (err < 0)
390                 return err;
391         if (tb[TCA_FQ_CODEL_FLOWS]) {
392                 if (q->flows)
393                         return -EINVAL;
394                 q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]);
395                 if (!q->flows_cnt ||
396                     q->flows_cnt > 65536)
397                         return -EINVAL;
398         }
399         sch_tree_lock(sch);
400
401         if (tb[TCA_FQ_CODEL_TARGET]) {
402                 u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
403
404                 q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT;
405         }
406
407         if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) {
408                 u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]);
409
410                 q->cparams.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT;
411         }
412
413         if (tb[TCA_FQ_CODEL_INTERVAL]) {
414                 u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
415
416                 q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT;
417         }
418
419         if (tb[TCA_FQ_CODEL_LIMIT])
420                 sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]);
421
422         if (tb[TCA_FQ_CODEL_ECN])
423                 q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]);
424
425         if (tb[TCA_FQ_CODEL_QUANTUM])
426                 q->quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM]));
427
428         if (tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])
429                 q->drop_batch_size = min(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE]));
430
431         if (tb[TCA_FQ_CODEL_MEMORY_LIMIT])
432                 q->memory_limit = min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT]));
433
434         while (sch->q.qlen > sch->limit ||
435                q->memory_usage > q->memory_limit) {
436                 struct sk_buff *skb = fq_codel_dequeue(sch);
437
438                 q->cstats.drop_len += qdisc_pkt_len(skb);
439                 rtnl_kfree_skbs(skb, skb);
440                 q->cstats.drop_count++;
441         }
442         qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, q->cstats.drop_len);
443         q->cstats.drop_count = 0;
444         q->cstats.drop_len = 0;
445
446         sch_tree_unlock(sch);
447         return 0;
448 }
449
450 static void *fq_codel_zalloc(size_t sz)
451 {
452         void *ptr = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN);
453
454         if (!ptr)
455                 ptr = vzalloc(sz);
456         return ptr;
457 }
458
459 static void fq_codel_free(void *addr)
460 {
461         kvfree(addr);
462 }
463
464 static void fq_codel_destroy(struct Qdisc *sch)
465 {
466         struct fq_codel_sched_data *q = qdisc_priv(sch);
467
468         tcf_destroy_chain(&q->filter_list);
469         fq_codel_free(q->backlogs);
470         fq_codel_free(q->flows);
471 }
472
473 static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt)
474 {
475         struct fq_codel_sched_data *q = qdisc_priv(sch);
476         int i;
477
478         sch->limit = 10*1024;
479         q->flows_cnt = 1024;
480         q->memory_limit = 32 << 20; /* 32 MBytes */
481         q->drop_batch_size = 64;
482         q->quantum = psched_mtu(qdisc_dev(sch));
483         INIT_LIST_HEAD(&q->new_flows);
484         INIT_LIST_HEAD(&q->old_flows);
485         codel_params_init(&q->cparams);
486         codel_stats_init(&q->cstats);
487         q->cparams.ecn = true;
488         q->cparams.mtu = psched_mtu(qdisc_dev(sch));
489
490         if (opt) {
491                 int err = fq_codel_change(sch, opt);
492                 if (err)
493                         return err;
494         }
495
496         if (!q->flows) {
497                 q->flows = fq_codel_zalloc(q->flows_cnt *
498                                            sizeof(struct fq_codel_flow));
499                 if (!q->flows)
500                         return -ENOMEM;
501                 q->backlogs = fq_codel_zalloc(q->flows_cnt * sizeof(u32));
502                 if (!q->backlogs) {
503                         fq_codel_free(q->flows);
504                         return -ENOMEM;
505                 }
506                 for (i = 0; i < q->flows_cnt; i++) {
507                         struct fq_codel_flow *flow = q->flows + i;
508
509                         INIT_LIST_HEAD(&flow->flowchain);
510                         codel_vars_init(&flow->cvars);
511                 }
512         }
513         if (sch->limit >= 1)
514                 sch->flags |= TCQ_F_CAN_BYPASS;
515         else
516                 sch->flags &= ~TCQ_F_CAN_BYPASS;
517         return 0;
518 }
519
520 static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
521 {
522         struct fq_codel_sched_data *q = qdisc_priv(sch);
523         struct nlattr *opts;
524
525         opts = nla_nest_start(skb, TCA_OPTIONS);
526         if (opts == NULL)
527                 goto nla_put_failure;
528
529         if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET,
530                         codel_time_to_us(q->cparams.target)) ||
531             nla_put_u32(skb, TCA_FQ_CODEL_LIMIT,
532                         sch->limit) ||
533             nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL,
534                         codel_time_to_us(q->cparams.interval)) ||
535             nla_put_u32(skb, TCA_FQ_CODEL_ECN,
536                         q->cparams.ecn) ||
537             nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
538                         q->quantum) ||
539             nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE,
540                         q->drop_batch_size) ||
541             nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT,
542                         q->memory_limit) ||
543             nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
544                         q->flows_cnt))
545                 goto nla_put_failure;
546
547         if (q->cparams.ce_threshold != CODEL_DISABLED_THRESHOLD &&
548             nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD,
549                         codel_time_to_us(q->cparams.ce_threshold)))
550                 goto nla_put_failure;
551
552         return nla_nest_end(skb, opts);
553
554 nla_put_failure:
555         return -1;
556 }
557
558 static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
559 {
560         struct fq_codel_sched_data *q = qdisc_priv(sch);
561         struct tc_fq_codel_xstats st = {
562                 .type                           = TCA_FQ_CODEL_XSTATS_QDISC,
563         };
564         struct list_head *pos;
565
566         st.qdisc_stats.maxpacket = q->cstats.maxpacket;
567         st.qdisc_stats.drop_overlimit = q->drop_overlimit;
568         st.qdisc_stats.ecn_mark = q->cstats.ecn_mark;
569         st.qdisc_stats.new_flow_count = q->new_flow_count;
570         st.qdisc_stats.ce_mark = q->cstats.ce_mark;
571         st.qdisc_stats.memory_usage  = q->memory_usage;
572         st.qdisc_stats.drop_overmemory = q->drop_overmemory;
573
574         sch_tree_lock(sch);
575         list_for_each(pos, &q->new_flows)
576                 st.qdisc_stats.new_flows_len++;
577
578         list_for_each(pos, &q->old_flows)
579                 st.qdisc_stats.old_flows_len++;
580         sch_tree_unlock(sch);
581
582         return gnet_stats_copy_app(d, &st, sizeof(st));
583 }
584
585 static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg)
586 {
587         return NULL;
588 }
589
590 static unsigned long fq_codel_get(struct Qdisc *sch, u32 classid)
591 {
592         return 0;
593 }
594
595 static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent,
596                               u32 classid)
597 {
598         /* we cannot bypass queue discipline anymore */
599         sch->flags &= ~TCQ_F_CAN_BYPASS;
600         return 0;
601 }
602
603 static void fq_codel_put(struct Qdisc *q, unsigned long cl)
604 {
605 }
606
607 static struct tcf_proto __rcu **fq_codel_find_tcf(struct Qdisc *sch,
608                                                   unsigned long cl)
609 {
610         struct fq_codel_sched_data *q = qdisc_priv(sch);
611
612         if (cl)
613                 return NULL;
614         return &q->filter_list;
615 }
616
617 static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl,
618                           struct sk_buff *skb, struct tcmsg *tcm)
619 {
620         tcm->tcm_handle |= TC_H_MIN(cl);
621         return 0;
622 }
623
624 static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl,
625                                      struct gnet_dump *d)
626 {
627         struct fq_codel_sched_data *q = qdisc_priv(sch);
628         u32 idx = cl - 1;
629         struct gnet_stats_queue qs = { 0 };
630         struct tc_fq_codel_xstats xstats;
631
632         if (idx < q->flows_cnt) {
633                 const struct fq_codel_flow *flow = &q->flows[idx];
634                 const struct sk_buff *skb;
635
636                 memset(&xstats, 0, sizeof(xstats));
637                 xstats.type = TCA_FQ_CODEL_XSTATS_CLASS;
638                 xstats.class_stats.deficit = flow->deficit;
639                 xstats.class_stats.ldelay =
640                         codel_time_to_us(flow->cvars.ldelay);
641                 xstats.class_stats.count = flow->cvars.count;
642                 xstats.class_stats.lastcount = flow->cvars.lastcount;
643                 xstats.class_stats.dropping = flow->cvars.dropping;
644                 if (flow->cvars.dropping) {
645                         codel_tdiff_t delta = flow->cvars.drop_next -
646                                               codel_get_time();
647
648                         xstats.class_stats.drop_next = (delta >= 0) ?
649                                 codel_time_to_us(delta) :
650                                 -codel_time_to_us(-delta);
651                 }
652                 if (flow->head) {
653                         sch_tree_lock(sch);
654                         skb = flow->head;
655                         while (skb) {
656                                 qs.qlen++;
657                                 skb = skb->next;
658                         }
659                         sch_tree_unlock(sch);
660                 }
661                 qs.backlog = q->backlogs[idx];
662                 qs.drops = flow->dropped;
663         }
664         if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
665                 return -1;
666         if (idx < q->flows_cnt)
667                 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
668         return 0;
669 }
670
671 static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg)
672 {
673         struct fq_codel_sched_data *q = qdisc_priv(sch);
674         unsigned int i;
675
676         if (arg->stop)
677                 return;
678
679         for (i = 0; i < q->flows_cnt; i++) {
680                 if (list_empty(&q->flows[i].flowchain) ||
681                     arg->count < arg->skip) {
682                         arg->count++;
683                         continue;
684                 }
685                 if (arg->fn(sch, i + 1, arg) < 0) {
686                         arg->stop = 1;
687                         break;
688                 }
689                 arg->count++;
690         }
691 }
692
693 static const struct Qdisc_class_ops fq_codel_class_ops = {
694         .leaf           =       fq_codel_leaf,
695         .get            =       fq_codel_get,
696         .put            =       fq_codel_put,
697         .tcf_chain      =       fq_codel_find_tcf,
698         .bind_tcf       =       fq_codel_bind,
699         .unbind_tcf     =       fq_codel_put,
700         .dump           =       fq_codel_dump_class,
701         .dump_stats     =       fq_codel_dump_class_stats,
702         .walk           =       fq_codel_walk,
703 };
704
705 static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = {
706         .cl_ops         =       &fq_codel_class_ops,
707         .id             =       "fq_codel",
708         .priv_size      =       sizeof(struct fq_codel_sched_data),
709         .enqueue        =       fq_codel_enqueue,
710         .dequeue        =       fq_codel_dequeue,
711         .peek           =       qdisc_peek_dequeued,
712         .init           =       fq_codel_init,
713         .reset          =       fq_codel_reset,
714         .destroy        =       fq_codel_destroy,
715         .change         =       fq_codel_change,
716         .dump           =       fq_codel_dump,
717         .dump_stats =   fq_codel_dump_stats,
718         .owner          =       THIS_MODULE,
719 };
720
721 static int __init fq_codel_module_init(void)
722 {
723         return register_qdisc(&fq_codel_qdisc_ops);
724 }
725
726 static void __exit fq_codel_module_exit(void)
727 {
728         unregister_qdisc(&fq_codel_qdisc_ops);
729 }
730
731 module_init(fq_codel_module_init)
732 module_exit(fq_codel_module_exit)
733 MODULE_AUTHOR("Eric Dumazet");
734 MODULE_LICENSE("GPL");