1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Fair Queue CoDel discipline 4 * 5 * Copyright (C) 2012,2015 Eric Dumazet <edumazet@google.com> 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/slab.h> 18 #include <linux/vmalloc.h> 19 #include <net/netlink.h> 20 #include <net/pkt_sched.h> 21 #include <net/pkt_cls.h> 22 #include <net/codel.h> 23 #include <net/codel_impl.h> 24 #include <net/codel_qdisc.h> 25 26 /* Fair Queue CoDel. 27 * 28 * Principles : 29 * Packets are classified (internal classifier or external) on flows. 30 * This is a Stochastic model (as we use a hash, several flows 31 * might be hashed on same slot) 32 * Each flow has a CoDel managed queue. 33 * Flows are linked onto two (Round Robin) lists, 34 * so that new flows have priority on old ones. 35 * 36 * For a given flow, packets are not reordered (CoDel uses a FIFO) 37 * head drops only. 38 * ECN capability is on by default. 39 * Low memory footprint (64 bytes per flow) 40 */ 41 42 struct fq_codel_flow { 43 struct sk_buff *head; 44 struct sk_buff *tail; 45 struct list_head flowchain; 46 int deficit; 47 struct codel_vars cvars; 48 }; /* please try to keep this structure <= 64 bytes */ 49 50 struct fq_codel_sched_data { 51 struct tcf_proto __rcu *filter_list; /* optional external classifier */ 52 struct tcf_block *block; 53 struct fq_codel_flow *flows; /* Flows table [flows_cnt] */ 54 u32 *backlogs; /* backlog table [flows_cnt] */ 55 u32 flows_cnt; /* number of flows */ 56 u32 quantum; /* psched_mtu(qdisc_dev(sch)); */ 57 u32 drop_batch_size; 58 u32 memory_limit; 59 struct codel_params cparams; 60 struct codel_stats cstats; 61 u32 memory_usage; 62 u32 drop_overmemory; 63 u32 drop_overlimit; 64 u32 new_flow_count; 65 66 struct list_head new_flows; /* list of new flows */ 67 struct list_head old_flows; /* list of old flows */ 68 }; 69 70 static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q, 71 struct sk_buff *skb) 72 { 73 return reciprocal_scale(skb_get_hash(skb), q->flows_cnt); 74 } 75 76 static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch, 77 int *qerr) 78 { 79 struct fq_codel_sched_data *q = qdisc_priv(sch); 80 struct tcf_proto *filter; 81 struct tcf_result res; 82 int result; 83 84 if (TC_H_MAJ(skb->priority) == sch->handle && 85 TC_H_MIN(skb->priority) > 0 && 86 TC_H_MIN(skb->priority) <= q->flows_cnt) 87 return TC_H_MIN(skb->priority); 88 89 filter = rcu_dereference_bh(q->filter_list); 90 if (!filter) 91 return fq_codel_hash(q, skb) + 1; 92 93 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 94 result = tcf_classify(skb, NULL, filter, &res, false); 95 if (result >= 0) { 96 #ifdef CONFIG_NET_CLS_ACT 97 switch (result) { 98 case TC_ACT_STOLEN: 99 case TC_ACT_QUEUED: 100 case TC_ACT_TRAP: 101 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 102 fallthrough; 103 case TC_ACT_SHOT: 104 return 0; 105 } 106 #endif 107 if (TC_H_MIN(res.classid) <= q->flows_cnt) 108 return TC_H_MIN(res.classid); 109 } 110 return 0; 111 } 112 113 /* helper functions : might be changed when/if skb use a standard list_head */ 114 115 /* remove one skb from head of slot queue */ 116 static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow) 117 { 118 struct sk_buff *skb = flow->head; 119 120 flow->head = skb->next; 121 skb_mark_not_on_list(skb); 122 return skb; 123 } 124 125 /* add skb to flow queue (tail add) */ 126 static inline void flow_queue_add(struct fq_codel_flow *flow, 127 struct sk_buff *skb) 128 { 129 if (flow->head == NULL) 130 flow->head = skb; 131 else 132 flow->tail->next = skb; 133 flow->tail = skb; 134 skb->next = NULL; 135 } 136 137 static unsigned int fq_codel_drop(struct Qdisc *sch, unsigned int max_packets, 138 struct sk_buff **to_free) 139 { 140 struct fq_codel_sched_data *q = qdisc_priv(sch); 141 struct sk_buff *skb; 142 unsigned int maxbacklog = 0, idx = 0, i, len; 143 struct fq_codel_flow *flow; 144 unsigned int threshold; 145 unsigned int mem = 0; 146 147 /* Queue is full! Find the fat flow and drop packet(s) from it. 148 * This might sound expensive, but with 1024 flows, we scan 149 * 4KB of memory, and we dont need to handle a complex tree 150 * in fast path (packet queue/enqueue) with many cache misses. 151 * In stress mode, we'll try to drop 64 packets from the flow, 152 * amortizing this linear lookup to one cache line per drop. 153 */ 154 for (i = 0; i < q->flows_cnt; i++) { 155 if (q->backlogs[i] > maxbacklog) { 156 maxbacklog = q->backlogs[i]; 157 idx = i; 158 } 159 } 160 161 /* Our goal is to drop half of this fat flow backlog */ 162 threshold = maxbacklog >> 1; 163 164 flow = &q->flows[idx]; 165 len = 0; 166 i = 0; 167 do { 168 skb = dequeue_head(flow); 169 len += qdisc_pkt_len(skb); 170 mem += get_codel_cb(skb)->mem_usage; 171 tcf_set_drop_reason(skb, SKB_DROP_REASON_QDISC_OVERLIMIT); 172 __qdisc_drop(skb, to_free); 173 } while (++i < max_packets && len < threshold); 174 175 /* Tell codel to increase its signal strength also */ 176 flow->cvars.count += i; 177 q->backlogs[idx] -= len; 178 q->memory_usage -= mem; 179 sch->qstats.drops += i; 180 sch->qstats.backlog -= len; 181 sch->q.qlen -= i; 182 return idx; 183 } 184 185 static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch, 186 struct sk_buff **to_free) 187 { 188 struct fq_codel_sched_data *q = qdisc_priv(sch); 189 unsigned int idx, prev_backlog, prev_qlen; 190 struct fq_codel_flow *flow; 191 int ret; 192 unsigned int pkt_len; 193 bool memory_limited; 194 195 idx = fq_codel_classify(skb, sch, &ret); 196 if (idx == 0) { 197 if (ret & __NET_XMIT_BYPASS) 198 qdisc_qstats_drop(sch); 199 __qdisc_drop(skb, to_free); 200 return ret; 201 } 202 idx--; 203 204 codel_set_enqueue_time(skb); 205 flow = &q->flows[idx]; 206 flow_queue_add(flow, skb); 207 q->backlogs[idx] += qdisc_pkt_len(skb); 208 qdisc_qstats_backlog_inc(sch, skb); 209 210 if (list_empty(&flow->flowchain)) { 211 list_add_tail(&flow->flowchain, &q->new_flows); 212 q->new_flow_count++; 213 flow->deficit = q->quantum; 214 } 215 get_codel_cb(skb)->mem_usage = skb->truesize; 216 q->memory_usage += get_codel_cb(skb)->mem_usage; 217 memory_limited = q->memory_usage > q->memory_limit; 218 if (++sch->q.qlen <= sch->limit && !memory_limited) 219 return NET_XMIT_SUCCESS; 220 221 prev_backlog = sch->qstats.backlog; 222 prev_qlen = sch->q.qlen; 223 224 /* save this packet length as it might be dropped by fq_codel_drop() */ 225 pkt_len = qdisc_pkt_len(skb); 226 /* fq_codel_drop() is quite expensive, as it performs a linear search 227 * in q->backlogs[] to find a fat flow. 228 * So instead of dropping a single packet, drop half of its backlog 229 * with a 64 packets limit to not add a too big cpu spike here. 230 */ 231 ret = fq_codel_drop(sch, q->drop_batch_size, to_free); 232 233 prev_qlen -= sch->q.qlen; 234 prev_backlog -= sch->qstats.backlog; 235 q->drop_overlimit += prev_qlen; 236 if (memory_limited) 237 q->drop_overmemory += prev_qlen; 238 239 /* As we dropped packet(s), better let upper stack know this. 240 * If we dropped a packet for this flow, return NET_XMIT_CN, 241 * but in this case, our parents wont increase their backlogs. 242 */ 243 if (ret == idx) { 244 qdisc_tree_reduce_backlog(sch, prev_qlen - 1, 245 prev_backlog - pkt_len); 246 return NET_XMIT_CN; 247 } 248 qdisc_tree_reduce_backlog(sch, prev_qlen, prev_backlog); 249 return NET_XMIT_SUCCESS; 250 } 251 252 /* This is the specific function called from codel_dequeue() 253 * to dequeue a packet from queue. Note: backlog is handled in 254 * codel, we dont need to reduce it here. 255 */ 256 static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx) 257 { 258 struct Qdisc *sch = ctx; 259 struct fq_codel_sched_data *q = qdisc_priv(sch); 260 struct fq_codel_flow *flow; 261 struct sk_buff *skb = NULL; 262 263 flow = container_of(vars, struct fq_codel_flow, cvars); 264 if (flow->head) { 265 skb = dequeue_head(flow); 266 q->backlogs[flow - q->flows] -= qdisc_pkt_len(skb); 267 q->memory_usage -= get_codel_cb(skb)->mem_usage; 268 sch->q.qlen--; 269 sch->qstats.backlog -= qdisc_pkt_len(skb); 270 } 271 return skb; 272 } 273 274 static void drop_func(struct sk_buff *skb, void *ctx) 275 { 276 struct Qdisc *sch = ctx; 277 278 qdisc_dequeue_drop(sch, skb, SKB_DROP_REASON_QDISC_CONGESTED); 279 qdisc_qstats_drop(sch); 280 } 281 282 static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch) 283 { 284 struct fq_codel_sched_data *q = qdisc_priv(sch); 285 struct sk_buff *skb; 286 struct fq_codel_flow *flow; 287 struct list_head *head; 288 289 begin: 290 head = &q->new_flows; 291 if (list_empty(head)) { 292 head = &q->old_flows; 293 if (list_empty(head)) 294 return NULL; 295 } 296 flow = list_first_entry(head, struct fq_codel_flow, flowchain); 297 298 if (flow->deficit <= 0) { 299 flow->deficit += q->quantum; 300 list_move_tail(&flow->flowchain, &q->old_flows); 301 goto begin; 302 } 303 304 skb = codel_dequeue(sch, &sch->qstats.backlog, &q->cparams, 305 &flow->cvars, &q->cstats, qdisc_pkt_len, 306 codel_get_enqueue_time, drop_func, dequeue_func); 307 308 if (!skb) { 309 /* force a pass through old_flows to prevent starvation */ 310 if ((head == &q->new_flows) && !list_empty(&q->old_flows)) 311 list_move_tail(&flow->flowchain, &q->old_flows); 312 else 313 list_del_init(&flow->flowchain); 314 goto begin; 315 } 316 qdisc_bstats_update(sch, skb); 317 flow->deficit -= qdisc_pkt_len(skb); 318 319 if (q->cstats.drop_count) { 320 qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, 321 q->cstats.drop_len); 322 q->cstats.drop_count = 0; 323 q->cstats.drop_len = 0; 324 } 325 return skb; 326 } 327 328 static void fq_codel_flow_purge(struct fq_codel_flow *flow) 329 { 330 rtnl_kfree_skbs(flow->head, flow->tail); 331 flow->head = NULL; 332 } 333 334 static void fq_codel_reset(struct Qdisc *sch) 335 { 336 struct fq_codel_sched_data *q = qdisc_priv(sch); 337 int i; 338 339 INIT_LIST_HEAD(&q->new_flows); 340 INIT_LIST_HEAD(&q->old_flows); 341 for (i = 0; i < q->flows_cnt; i++) { 342 struct fq_codel_flow *flow = q->flows + i; 343 344 fq_codel_flow_purge(flow); 345 INIT_LIST_HEAD(&flow->flowchain); 346 codel_vars_init(&flow->cvars); 347 } 348 memset(q->backlogs, 0, q->flows_cnt * sizeof(u32)); 349 q->memory_usage = 0; 350 } 351 352 static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = { 353 [TCA_FQ_CODEL_TARGET] = { .type = NLA_U32 }, 354 [TCA_FQ_CODEL_LIMIT] = { .type = NLA_U32 }, 355 [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 }, 356 [TCA_FQ_CODEL_ECN] = { .type = NLA_U32 }, 357 [TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 }, 358 [TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 }, 359 [TCA_FQ_CODEL_CE_THRESHOLD] = { .type = NLA_U32 }, 360 [TCA_FQ_CODEL_DROP_BATCH_SIZE] = { .type = NLA_U32 }, 361 [TCA_FQ_CODEL_MEMORY_LIMIT] = { .type = NLA_U32 }, 362 [TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR] = { .type = NLA_U8 }, 363 [TCA_FQ_CODEL_CE_THRESHOLD_MASK] = { .type = NLA_U8 }, 364 }; 365 366 static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt, 367 struct netlink_ext_ack *extack) 368 { 369 unsigned int dropped_pkts = 0, dropped_bytes = 0; 370 struct fq_codel_sched_data *q = qdisc_priv(sch); 371 struct nlattr *tb[TCA_FQ_CODEL_MAX + 1]; 372 u32 quantum = 0; 373 int err; 374 375 err = nla_parse_nested_deprecated(tb, TCA_FQ_CODEL_MAX, opt, 376 fq_codel_policy, NULL); 377 if (err < 0) 378 return err; 379 if (tb[TCA_FQ_CODEL_FLOWS]) { 380 if (q->flows) 381 return -EINVAL; 382 q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]); 383 if (!q->flows_cnt || 384 q->flows_cnt > 65536) 385 return -EINVAL; 386 } 387 if (tb[TCA_FQ_CODEL_QUANTUM]) { 388 quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM])); 389 if (quantum > FQ_CODEL_QUANTUM_MAX) { 390 NL_SET_ERR_MSG(extack, "Invalid quantum"); 391 return -EINVAL; 392 } 393 } 394 sch_tree_lock(sch); 395 396 if (tb[TCA_FQ_CODEL_TARGET]) { 397 u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]); 398 399 WRITE_ONCE(q->cparams.target, 400 (target * NSEC_PER_USEC) >> CODEL_SHIFT); 401 } 402 403 if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) { 404 u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]); 405 406 WRITE_ONCE(q->cparams.ce_threshold, 407 (val * NSEC_PER_USEC) >> CODEL_SHIFT); 408 } 409 410 if (tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR]) 411 WRITE_ONCE(q->cparams.ce_threshold_selector, 412 nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR])); 413 if (tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK]) 414 WRITE_ONCE(q->cparams.ce_threshold_mask, 415 nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK])); 416 417 if (tb[TCA_FQ_CODEL_INTERVAL]) { 418 u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]); 419 420 WRITE_ONCE(q->cparams.interval, 421 (interval * NSEC_PER_USEC) >> CODEL_SHIFT); 422 } 423 424 if (tb[TCA_FQ_CODEL_LIMIT]) 425 WRITE_ONCE(sch->limit, 426 nla_get_u32(tb[TCA_FQ_CODEL_LIMIT])); 427 428 if (tb[TCA_FQ_CODEL_ECN]) 429 WRITE_ONCE(q->cparams.ecn, 430 !!nla_get_u32(tb[TCA_FQ_CODEL_ECN])); 431 432 if (quantum) 433 WRITE_ONCE(q->quantum, quantum); 434 435 if (tb[TCA_FQ_CODEL_DROP_BATCH_SIZE]) 436 WRITE_ONCE(q->drop_batch_size, 437 max(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE]))); 438 439 if (tb[TCA_FQ_CODEL_MEMORY_LIMIT]) 440 WRITE_ONCE(q->memory_limit, 441 min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT]))); 442 443 while (sch->q.qlen > sch->limit || 444 q->memory_usage > q->memory_limit) { 445 struct sk_buff *skb = qdisc_dequeue_internal(sch, false); 446 447 if (!skb) 448 break; 449 450 dropped_pkts++; 451 dropped_bytes += qdisc_pkt_len(skb); 452 rtnl_kfree_skbs(skb, skb); 453 } 454 qdisc_tree_reduce_backlog(sch, dropped_pkts, dropped_bytes); 455 456 sch_tree_unlock(sch); 457 return 0; 458 } 459 460 static void fq_codel_destroy(struct Qdisc *sch) 461 { 462 struct fq_codel_sched_data *q = qdisc_priv(sch); 463 464 tcf_block_put(q->block); 465 kvfree(q->backlogs); 466 kvfree(q->flows); 467 } 468 469 static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt, 470 struct netlink_ext_ack *extack) 471 { 472 struct fq_codel_sched_data *q = qdisc_priv(sch); 473 int i; 474 int err; 475 476 sch->limit = 10*1024; 477 q->flows_cnt = 1024; 478 q->memory_limit = 32 << 20; /* 32 MBytes */ 479 q->drop_batch_size = 64; 480 q->quantum = psched_mtu(qdisc_dev(sch)); 481 INIT_LIST_HEAD(&q->new_flows); 482 INIT_LIST_HEAD(&q->old_flows); 483 codel_params_init(&q->cparams); 484 codel_stats_init(&q->cstats); 485 q->cparams.ecn = true; 486 q->cparams.mtu = psched_mtu(qdisc_dev(sch)); 487 488 if (opt) { 489 err = fq_codel_change(sch, opt, extack); 490 if (err) 491 goto init_failure; 492 } 493 494 err = tcf_block_get(&q->block, &q->filter_list, sch, extack); 495 if (err) 496 goto init_failure; 497 498 if (!q->flows) { 499 q->flows = kvcalloc(q->flows_cnt, 500 sizeof(struct fq_codel_flow), 501 GFP_KERNEL); 502 if (!q->flows) { 503 err = -ENOMEM; 504 goto init_failure; 505 } 506 q->backlogs = kvcalloc(q->flows_cnt, sizeof(u32), GFP_KERNEL); 507 if (!q->backlogs) { 508 err = -ENOMEM; 509 goto alloc_failure; 510 } 511 for (i = 0; i < q->flows_cnt; i++) { 512 struct fq_codel_flow *flow = q->flows + i; 513 514 INIT_LIST_HEAD(&flow->flowchain); 515 codel_vars_init(&flow->cvars); 516 } 517 } 518 if (sch->limit >= 1) 519 sch->flags |= TCQ_F_CAN_BYPASS; 520 else 521 sch->flags &= ~TCQ_F_CAN_BYPASS; 522 523 sch->flags |= TCQ_F_DEQUEUE_DROPS; 524 525 return 0; 526 527 alloc_failure: 528 kvfree(q->flows); 529 q->flows = NULL; 530 init_failure: 531 q->flows_cnt = 0; 532 return err; 533 } 534 535 static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb) 536 { 537 struct fq_codel_sched_data *q = qdisc_priv(sch); 538 codel_time_t ce_threshold; 539 struct nlattr *opts; 540 541 opts = nla_nest_start_noflag(skb, TCA_OPTIONS); 542 if (opts == NULL) 543 goto nla_put_failure; 544 545 if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET, 546 codel_time_to_us(READ_ONCE(q->cparams.target))) || 547 nla_put_u32(skb, TCA_FQ_CODEL_LIMIT, 548 READ_ONCE(sch->limit)) || 549 nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL, 550 codel_time_to_us(READ_ONCE(q->cparams.interval))) || 551 nla_put_u32(skb, TCA_FQ_CODEL_ECN, 552 READ_ONCE(q->cparams.ecn)) || 553 nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM, 554 READ_ONCE(q->quantum)) || 555 nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE, 556 READ_ONCE(q->drop_batch_size)) || 557 nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT, 558 READ_ONCE(q->memory_limit)) || 559 nla_put_u32(skb, TCA_FQ_CODEL_FLOWS, 560 READ_ONCE(q->flows_cnt))) 561 goto nla_put_failure; 562 563 ce_threshold = READ_ONCE(q->cparams.ce_threshold); 564 if (ce_threshold != CODEL_DISABLED_THRESHOLD) { 565 if (nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD, 566 codel_time_to_us(ce_threshold))) 567 goto nla_put_failure; 568 if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR, 569 READ_ONCE(q->cparams.ce_threshold_selector))) 570 goto nla_put_failure; 571 if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_MASK, 572 READ_ONCE(q->cparams.ce_threshold_mask))) 573 goto nla_put_failure; 574 } 575 576 return nla_nest_end(skb, opts); 577 578 nla_put_failure: 579 return -1; 580 } 581 582 static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d) 583 { 584 struct fq_codel_sched_data *q = qdisc_priv(sch); 585 struct tc_fq_codel_xstats st = { 586 .type = TCA_FQ_CODEL_XSTATS_QDISC, 587 }; 588 struct list_head *pos; 589 590 st.qdisc_stats.maxpacket = q->cstats.maxpacket; 591 st.qdisc_stats.drop_overlimit = q->drop_overlimit; 592 st.qdisc_stats.ecn_mark = q->cstats.ecn_mark; 593 st.qdisc_stats.new_flow_count = q->new_flow_count; 594 st.qdisc_stats.ce_mark = q->cstats.ce_mark; 595 st.qdisc_stats.memory_usage = q->memory_usage; 596 st.qdisc_stats.drop_overmemory = q->drop_overmemory; 597 598 sch_tree_lock(sch); 599 list_for_each(pos, &q->new_flows) 600 st.qdisc_stats.new_flows_len++; 601 602 list_for_each(pos, &q->old_flows) 603 st.qdisc_stats.old_flows_len++; 604 sch_tree_unlock(sch); 605 606 return gnet_stats_copy_app(d, &st, sizeof(st)); 607 } 608 609 static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg) 610 { 611 return NULL; 612 } 613 614 static unsigned long fq_codel_find(struct Qdisc *sch, u32 classid) 615 { 616 return 0; 617 } 618 619 static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent, 620 u32 classid) 621 { 622 return 0; 623 } 624 625 static void fq_codel_unbind(struct Qdisc *q, unsigned long cl) 626 { 627 } 628 629 static struct tcf_block *fq_codel_tcf_block(struct Qdisc *sch, unsigned long cl, 630 struct netlink_ext_ack *extack) 631 { 632 struct fq_codel_sched_data *q = qdisc_priv(sch); 633 634 if (cl) 635 return NULL; 636 return q->block; 637 } 638 639 static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl, 640 struct sk_buff *skb, struct tcmsg *tcm) 641 { 642 tcm->tcm_handle |= TC_H_MIN(cl); 643 return 0; 644 } 645 646 static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl, 647 struct gnet_dump *d) 648 { 649 struct fq_codel_sched_data *q = qdisc_priv(sch); 650 u32 idx = cl - 1; 651 struct gnet_stats_queue qs = { 0 }; 652 struct tc_fq_codel_xstats xstats; 653 654 if (idx < q->flows_cnt) { 655 const struct fq_codel_flow *flow = &q->flows[idx]; 656 const struct sk_buff *skb; 657 658 memset(&xstats, 0, sizeof(xstats)); 659 xstats.type = TCA_FQ_CODEL_XSTATS_CLASS; 660 xstats.class_stats.deficit = flow->deficit; 661 xstats.class_stats.ldelay = 662 codel_time_to_us(flow->cvars.ldelay); 663 xstats.class_stats.count = flow->cvars.count; 664 xstats.class_stats.lastcount = flow->cvars.lastcount; 665 xstats.class_stats.dropping = flow->cvars.dropping; 666 if (flow->cvars.dropping) { 667 codel_tdiff_t delta = flow->cvars.drop_next - 668 codel_get_time(); 669 670 xstats.class_stats.drop_next = (delta >= 0) ? 671 codel_time_to_us(delta) : 672 -codel_time_to_us(-delta); 673 } 674 if (flow->head) { 675 sch_tree_lock(sch); 676 skb = flow->head; 677 while (skb) { 678 qs.qlen++; 679 skb = skb->next; 680 } 681 sch_tree_unlock(sch); 682 } 683 qs.backlog = q->backlogs[idx]; 684 qs.drops = 0; 685 } 686 if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0) 687 return -1; 688 if (idx < q->flows_cnt) 689 return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); 690 return 0; 691 } 692 693 static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg) 694 { 695 struct fq_codel_sched_data *q = qdisc_priv(sch); 696 unsigned int i; 697 698 if (arg->stop) 699 return; 700 701 for (i = 0; i < q->flows_cnt; i++) { 702 if (list_empty(&q->flows[i].flowchain)) { 703 arg->count++; 704 continue; 705 } 706 if (!tc_qdisc_stats_dump(sch, i + 1, arg)) 707 break; 708 } 709 } 710 711 static const struct Qdisc_class_ops fq_codel_class_ops = { 712 .leaf = fq_codel_leaf, 713 .find = fq_codel_find, 714 .tcf_block = fq_codel_tcf_block, 715 .bind_tcf = fq_codel_bind, 716 .unbind_tcf = fq_codel_unbind, 717 .dump = fq_codel_dump_class, 718 .dump_stats = fq_codel_dump_class_stats, 719 .walk = fq_codel_walk, 720 }; 721 722 static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = { 723 .cl_ops = &fq_codel_class_ops, 724 .id = "fq_codel", 725 .priv_size = sizeof(struct fq_codel_sched_data), 726 .enqueue = fq_codel_enqueue, 727 .dequeue = fq_codel_dequeue, 728 .peek = qdisc_peek_dequeued, 729 .init = fq_codel_init, 730 .reset = fq_codel_reset, 731 .destroy = fq_codel_destroy, 732 .change = fq_codel_change, 733 .dump = fq_codel_dump, 734 .dump_stats = fq_codel_dump_stats, 735 .owner = THIS_MODULE, 736 }; 737 MODULE_ALIAS_NET_SCH("fq_codel"); 738 739 static int __init fq_codel_module_init(void) 740 { 741 return register_qdisc(&fq_codel_qdisc_ops); 742 } 743 744 static void __exit fq_codel_module_exit(void) 745 { 746 unregister_qdisc(&fq_codel_qdisc_ops); 747 } 748 749 module_init(fq_codel_module_init) 750 module_exit(fq_codel_module_exit) 751 MODULE_AUTHOR("Eric Dumazet"); 752 MODULE_LICENSE("GPL"); 753 MODULE_DESCRIPTION("Fair Queue CoDel discipline"); 754