1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * net/sched/sch_generic.c Generic packet scheduler routines. 4 * 5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 6 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601 7 * - Ingress support 8 */ 9 10 #include <linux/bitops.h> 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/sched.h> 15 #include <linux/string.h> 16 #include <linux/errno.h> 17 #include <linux/netdevice.h> 18 #include <linux/skbuff.h> 19 #include <linux/rtnetlink.h> 20 #include <linux/init.h> 21 #include <linux/rcupdate.h> 22 #include <linux/list.h> 23 #include <linux/slab.h> 24 #include <linux/if_vlan.h> 25 #include <linux/skb_array.h> 26 #include <linux/if_macvlan.h> 27 #include <net/sch_generic.h> 28 #include <net/pkt_sched.h> 29 #include <net/dst.h> 30 #include <net/hotdata.h> 31 #include <trace/events/qdisc.h> 32 #include <trace/events/net.h> 33 #include <net/xfrm.h> 34 35 /* Qdisc to use by default */ 36 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops; 37 EXPORT_SYMBOL(default_qdisc_ops); 38 39 static void qdisc_maybe_clear_missed(struct Qdisc *q, 40 const struct netdev_queue *txq) 41 { 42 clear_bit(__QDISC_STATE_MISSED, &q->state); 43 44 /* Make sure the below netif_xmit_frozen_or_stopped() 45 * checking happens after clearing STATE_MISSED. 46 */ 47 smp_mb__after_atomic(); 48 49 /* Checking netif_xmit_frozen_or_stopped() again to 50 * make sure STATE_MISSED is set if the STATE_MISSED 51 * set by netif_tx_wake_queue()'s rescheduling of 52 * net_tx_action() is cleared by the above clear_bit(). 53 */ 54 if (!netif_xmit_frozen_or_stopped(txq)) 55 set_bit(__QDISC_STATE_MISSED, &q->state); 56 else 57 set_bit(__QDISC_STATE_DRAINING, &q->state); 58 } 59 60 /* Main transmission queue. */ 61 62 /* Modifications to data participating in scheduling must be protected with 63 * qdisc_lock(qdisc) spinlock. 64 * 65 * The idea is the following: 66 * - enqueue, dequeue are serialized via qdisc root lock 67 * - ingress filtering is also serialized via qdisc root lock 68 * - updates to tree and tree walking are only done under the rtnl mutex. 69 */ 70 71 #define SKB_XOFF_MAGIC ((struct sk_buff *)1UL) 72 73 static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q) 74 { 75 const struct netdev_queue *txq = q->dev_queue; 76 spinlock_t *lock = NULL; 77 struct sk_buff *skb; 78 79 if (q->flags & TCQ_F_NOLOCK) { 80 lock = qdisc_lock(q); 81 spin_lock(lock); 82 } 83 84 skb = skb_peek(&q->skb_bad_txq); 85 if (skb) { 86 /* check the reason of requeuing without tx lock first */ 87 txq = skb_get_tx_queue(txq->dev, skb); 88 if (!netif_xmit_frozen_or_stopped(txq)) { 89 skb = __skb_dequeue(&q->skb_bad_txq); 90 if (qdisc_is_percpu_stats(q)) { 91 qdisc_qstats_cpu_backlog_dec(q, skb); 92 qdisc_qstats_cpu_qlen_dec(q); 93 } else { 94 qdisc_qstats_backlog_dec(q, skb); 95 q->q.qlen--; 96 } 97 } else { 98 skb = SKB_XOFF_MAGIC; 99 qdisc_maybe_clear_missed(q, txq); 100 } 101 } 102 103 if (lock) 104 spin_unlock(lock); 105 106 return skb; 107 } 108 109 static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q) 110 { 111 struct sk_buff *skb = skb_peek(&q->skb_bad_txq); 112 113 if (unlikely(skb)) 114 skb = __skb_dequeue_bad_txq(q); 115 116 return skb; 117 } 118 119 static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q, 120 struct sk_buff *skb) 121 { 122 spinlock_t *lock = NULL; 123 124 if (q->flags & TCQ_F_NOLOCK) { 125 lock = qdisc_lock(q); 126 spin_lock(lock); 127 } 128 129 __skb_queue_tail(&q->skb_bad_txq, skb); 130 131 if (qdisc_is_percpu_stats(q)) { 132 qdisc_qstats_cpu_backlog_inc(q, skb); 133 qdisc_qstats_cpu_qlen_inc(q); 134 } else { 135 qdisc_qstats_backlog_inc(q, skb); 136 q->q.qlen++; 137 } 138 139 if (lock) 140 spin_unlock(lock); 141 } 142 143 static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q) 144 { 145 spinlock_t *lock = NULL; 146 147 if (q->flags & TCQ_F_NOLOCK) { 148 lock = qdisc_lock(q); 149 spin_lock(lock); 150 } 151 152 while (skb) { 153 struct sk_buff *next = skb->next; 154 155 __skb_queue_tail(&q->gso_skb, skb); 156 157 /* it's still part of the queue */ 158 if (qdisc_is_percpu_stats(q)) { 159 qdisc_qstats_cpu_requeues_inc(q); 160 qdisc_qstats_cpu_backlog_inc(q, skb); 161 qdisc_qstats_cpu_qlen_inc(q); 162 } else { 163 q->qstats.requeues++; 164 qdisc_qstats_backlog_inc(q, skb); 165 q->q.qlen++; 166 } 167 168 skb = next; 169 } 170 171 if (lock) { 172 spin_unlock(lock); 173 set_bit(__QDISC_STATE_MISSED, &q->state); 174 } else { 175 __netif_schedule(q); 176 } 177 } 178 179 static void try_bulk_dequeue_skb(struct Qdisc *q, 180 struct sk_buff *skb, 181 const struct netdev_queue *txq, 182 int *packets) 183 { 184 int bytelimit = qdisc_avail_bulklimit(txq) - skb->len; 185 186 while (bytelimit > 0) { 187 struct sk_buff *nskb = q->dequeue(q); 188 189 if (!nskb) 190 break; 191 192 bytelimit -= nskb->len; /* covers GSO len */ 193 skb->next = nskb; 194 skb = nskb; 195 (*packets)++; /* GSO counts as one pkt */ 196 } 197 skb_mark_not_on_list(skb); 198 } 199 200 /* This variant of try_bulk_dequeue_skb() makes sure 201 * all skbs in the chain are for the same txq 202 */ 203 static void try_bulk_dequeue_skb_slow(struct Qdisc *q, 204 struct sk_buff *skb, 205 int *packets) 206 { 207 int mapping = skb_get_queue_mapping(skb); 208 struct sk_buff *nskb; 209 int cnt = 0; 210 211 do { 212 nskb = q->dequeue(q); 213 if (!nskb) 214 break; 215 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) { 216 qdisc_enqueue_skb_bad_txq(q, nskb); 217 break; 218 } 219 skb->next = nskb; 220 skb = nskb; 221 } while (++cnt < 8); 222 (*packets) += cnt; 223 skb_mark_not_on_list(skb); 224 } 225 226 /* Note that dequeue_skb can possibly return a SKB list (via skb->next). 227 * A requeued skb (via q->gso_skb) can also be a SKB list. 228 */ 229 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate, 230 int *packets) 231 { 232 const struct netdev_queue *txq = q->dev_queue; 233 struct sk_buff *skb = NULL; 234 235 *packets = 1; 236 if (unlikely(!skb_queue_empty(&q->gso_skb))) { 237 spinlock_t *lock = NULL; 238 239 if (q->flags & TCQ_F_NOLOCK) { 240 lock = qdisc_lock(q); 241 spin_lock(lock); 242 } 243 244 skb = skb_peek(&q->gso_skb); 245 246 /* skb may be null if another cpu pulls gso_skb off in between 247 * empty check and lock. 248 */ 249 if (!skb) { 250 if (lock) 251 spin_unlock(lock); 252 goto validate; 253 } 254 255 /* skb in gso_skb were already validated */ 256 *validate = false; 257 if (xfrm_offload(skb)) 258 *validate = true; 259 /* check the reason of requeuing without tx lock first */ 260 txq = skb_get_tx_queue(txq->dev, skb); 261 if (!netif_xmit_frozen_or_stopped(txq)) { 262 skb = __skb_dequeue(&q->gso_skb); 263 if (qdisc_is_percpu_stats(q)) { 264 qdisc_qstats_cpu_backlog_dec(q, skb); 265 qdisc_qstats_cpu_qlen_dec(q); 266 } else { 267 qdisc_qstats_backlog_dec(q, skb); 268 q->q.qlen--; 269 } 270 } else { 271 skb = NULL; 272 qdisc_maybe_clear_missed(q, txq); 273 } 274 if (lock) 275 spin_unlock(lock); 276 goto trace; 277 } 278 validate: 279 *validate = true; 280 281 if ((q->flags & TCQ_F_ONETXQUEUE) && 282 netif_xmit_frozen_or_stopped(txq)) { 283 qdisc_maybe_clear_missed(q, txq); 284 return skb; 285 } 286 287 skb = qdisc_dequeue_skb_bad_txq(q); 288 if (unlikely(skb)) { 289 if (skb == SKB_XOFF_MAGIC) 290 return NULL; 291 goto bulk; 292 } 293 skb = q->dequeue(q); 294 if (skb) { 295 bulk: 296 if (qdisc_may_bulk(q)) 297 try_bulk_dequeue_skb(q, skb, txq, packets); 298 else 299 try_bulk_dequeue_skb_slow(q, skb, packets); 300 } 301 trace: 302 trace_qdisc_dequeue(q, txq, *packets, skb); 303 return skb; 304 } 305 306 /* 307 * Transmit possibly several skbs, and handle the return status as 308 * required. Owning qdisc running bit guarantees that only one CPU 309 * can execute this function. 310 * 311 * Returns to the caller: 312 * false - hardware queue frozen backoff 313 * true - feel free to send more pkts 314 */ 315 bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q, 316 struct net_device *dev, struct netdev_queue *txq, 317 spinlock_t *root_lock, bool validate) 318 { 319 int ret = NETDEV_TX_BUSY; 320 bool again = false; 321 322 /* And release qdisc */ 323 if (root_lock) 324 spin_unlock(root_lock); 325 326 /* Note that we validate skb (GSO, checksum, ...) outside of locks */ 327 if (validate) 328 skb = validate_xmit_skb_list(skb, dev, &again); 329 330 #ifdef CONFIG_XFRM_OFFLOAD 331 if (unlikely(again)) { 332 if (root_lock) 333 spin_lock(root_lock); 334 335 dev_requeue_skb(skb, q); 336 return false; 337 } 338 #endif 339 340 if (likely(skb)) { 341 HARD_TX_LOCK(dev, txq, smp_processor_id()); 342 if (!netif_xmit_frozen_or_stopped(txq)) 343 skb = dev_hard_start_xmit(skb, dev, txq, &ret); 344 else 345 qdisc_maybe_clear_missed(q, txq); 346 347 HARD_TX_UNLOCK(dev, txq); 348 } else { 349 if (root_lock) 350 spin_lock(root_lock); 351 return true; 352 } 353 354 if (root_lock) 355 spin_lock(root_lock); 356 357 if (!dev_xmit_complete(ret)) { 358 /* Driver returned NETDEV_TX_BUSY - requeue skb */ 359 if (unlikely(ret != NETDEV_TX_BUSY)) 360 net_warn_ratelimited("BUG %s code %d qlen %d\n", 361 dev->name, ret, q->q.qlen); 362 363 dev_requeue_skb(skb, q); 364 return false; 365 } 366 367 return true; 368 } 369 370 /* 371 * NOTE: Called under qdisc_lock(q) with locally disabled BH. 372 * 373 * running seqcount guarantees only one CPU can process 374 * this qdisc at a time. qdisc_lock(q) serializes queue accesses for 375 * this queue. 376 * 377 * netif_tx_lock serializes accesses to device driver. 378 * 379 * qdisc_lock(q) and netif_tx_lock are mutually exclusive, 380 * if one is grabbed, another must be free. 381 * 382 * Note, that this procedure can be called by a watchdog timer 383 * 384 * Returns to the caller: 385 * 0 - queue is empty or throttled. 386 * >0 - queue is not empty. 387 * 388 */ 389 static inline bool qdisc_restart(struct Qdisc *q, int *packets) 390 { 391 spinlock_t *root_lock = NULL; 392 struct netdev_queue *txq; 393 struct net_device *dev; 394 struct sk_buff *skb; 395 bool validate; 396 397 /* Dequeue packet */ 398 skb = dequeue_skb(q, &validate, packets); 399 if (unlikely(!skb)) 400 return false; 401 402 if (!(q->flags & TCQ_F_NOLOCK)) 403 root_lock = qdisc_lock(q); 404 405 dev = qdisc_dev(q); 406 txq = skb_get_tx_queue(dev, skb); 407 408 return sch_direct_xmit(skb, q, dev, txq, root_lock, validate); 409 } 410 411 void __qdisc_run(struct Qdisc *q) 412 { 413 int quota = READ_ONCE(net_hotdata.dev_tx_weight); 414 int packets; 415 416 while (qdisc_restart(q, &packets)) { 417 quota -= packets; 418 if (quota <= 0) { 419 if (q->flags & TCQ_F_NOLOCK) 420 set_bit(__QDISC_STATE_MISSED, &q->state); 421 else 422 __netif_schedule(q); 423 424 break; 425 } 426 } 427 } 428 429 unsigned long dev_trans_start(struct net_device *dev) 430 { 431 unsigned long res = READ_ONCE(netdev_get_tx_queue(dev, 0)->trans_start); 432 unsigned long val; 433 unsigned int i; 434 435 for (i = 1; i < dev->num_tx_queues; i++) { 436 val = READ_ONCE(netdev_get_tx_queue(dev, i)->trans_start); 437 if (val && time_after(val, res)) 438 res = val; 439 } 440 441 return res; 442 } 443 EXPORT_SYMBOL(dev_trans_start); 444 445 static void netif_freeze_queues(struct net_device *dev) 446 { 447 unsigned int i; 448 int cpu; 449 450 cpu = smp_processor_id(); 451 for (i = 0; i < dev->num_tx_queues; i++) { 452 struct netdev_queue *txq = netdev_get_tx_queue(dev, i); 453 454 /* We are the only thread of execution doing a 455 * freeze, but we have to grab the _xmit_lock in 456 * order to synchronize with threads which are in 457 * the ->hard_start_xmit() handler and already 458 * checked the frozen bit. 459 */ 460 __netif_tx_lock(txq, cpu); 461 set_bit(__QUEUE_STATE_FROZEN, &txq->state); 462 __netif_tx_unlock(txq); 463 } 464 } 465 466 void netif_tx_lock(struct net_device *dev) 467 { 468 spin_lock(&dev->tx_global_lock); 469 netif_freeze_queues(dev); 470 } 471 EXPORT_SYMBOL(netif_tx_lock); 472 473 static void netif_unfreeze_queues(struct net_device *dev) 474 { 475 unsigned int i; 476 477 for (i = 0; i < dev->num_tx_queues; i++) { 478 struct netdev_queue *txq = netdev_get_tx_queue(dev, i); 479 480 /* No need to grab the _xmit_lock here. If the 481 * queue is not stopped for another reason, we 482 * force a schedule. 483 */ 484 clear_bit(__QUEUE_STATE_FROZEN, &txq->state); 485 netif_schedule_queue(txq); 486 } 487 } 488 489 void netif_tx_unlock(struct net_device *dev) 490 { 491 netif_unfreeze_queues(dev); 492 spin_unlock(&dev->tx_global_lock); 493 } 494 EXPORT_SYMBOL(netif_tx_unlock); 495 496 static void dev_watchdog(struct timer_list *t) 497 { 498 struct net_device *dev = from_timer(dev, t, watchdog_timer); 499 bool release = true; 500 501 spin_lock(&dev->tx_global_lock); 502 if (!qdisc_tx_is_noop(dev)) { 503 if (netif_device_present(dev) && 504 netif_running(dev) && 505 netif_carrier_ok(dev)) { 506 unsigned int timedout_ms = 0; 507 unsigned int i; 508 unsigned long trans_start; 509 510 for (i = 0; i < dev->num_tx_queues; i++) { 511 struct netdev_queue *txq; 512 513 txq = netdev_get_tx_queue(dev, i); 514 trans_start = READ_ONCE(txq->trans_start); 515 if (netif_xmit_stopped(txq) && 516 time_after(jiffies, (trans_start + 517 dev->watchdog_timeo))) { 518 timedout_ms = jiffies_to_msecs(jiffies - trans_start); 519 atomic_long_inc(&txq->trans_timeout); 520 break; 521 } 522 } 523 524 if (unlikely(timedout_ms)) { 525 trace_net_dev_xmit_timeout(dev, i); 526 netdev_crit(dev, "NETDEV WATCHDOG: CPU: %d: transmit queue %u timed out %u ms\n", 527 raw_smp_processor_id(), 528 i, timedout_ms); 529 netif_freeze_queues(dev); 530 dev->netdev_ops->ndo_tx_timeout(dev, i); 531 netif_unfreeze_queues(dev); 532 } 533 if (!mod_timer(&dev->watchdog_timer, 534 round_jiffies(jiffies + 535 dev->watchdog_timeo))) 536 release = false; 537 } 538 } 539 spin_unlock(&dev->tx_global_lock); 540 541 if (release) 542 netdev_put(dev, &dev->watchdog_dev_tracker); 543 } 544 545 void __netdev_watchdog_up(struct net_device *dev) 546 { 547 if (dev->netdev_ops->ndo_tx_timeout) { 548 if (dev->watchdog_timeo <= 0) 549 dev->watchdog_timeo = 5*HZ; 550 if (!mod_timer(&dev->watchdog_timer, 551 round_jiffies(jiffies + dev->watchdog_timeo))) 552 netdev_hold(dev, &dev->watchdog_dev_tracker, 553 GFP_ATOMIC); 554 } 555 } 556 EXPORT_SYMBOL_GPL(__netdev_watchdog_up); 557 558 static void dev_watchdog_up(struct net_device *dev) 559 { 560 __netdev_watchdog_up(dev); 561 } 562 563 static void dev_watchdog_down(struct net_device *dev) 564 { 565 netif_tx_lock_bh(dev); 566 if (del_timer(&dev->watchdog_timer)) 567 netdev_put(dev, &dev->watchdog_dev_tracker); 568 netif_tx_unlock_bh(dev); 569 } 570 571 /** 572 * netif_carrier_on - set carrier 573 * @dev: network device 574 * 575 * Device has detected acquisition of carrier. 576 */ 577 void netif_carrier_on(struct net_device *dev) 578 { 579 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) { 580 if (dev->reg_state == NETREG_UNINITIALIZED) 581 return; 582 atomic_inc(&dev->carrier_up_count); 583 linkwatch_fire_event(dev); 584 if (netif_running(dev)) 585 __netdev_watchdog_up(dev); 586 } 587 } 588 EXPORT_SYMBOL(netif_carrier_on); 589 590 /** 591 * netif_carrier_off - clear carrier 592 * @dev: network device 593 * 594 * Device has detected loss of carrier. 595 */ 596 void netif_carrier_off(struct net_device *dev) 597 { 598 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) { 599 if (dev->reg_state == NETREG_UNINITIALIZED) 600 return; 601 atomic_inc(&dev->carrier_down_count); 602 linkwatch_fire_event(dev); 603 } 604 } 605 EXPORT_SYMBOL(netif_carrier_off); 606 607 /** 608 * netif_carrier_event - report carrier state event 609 * @dev: network device 610 * 611 * Device has detected a carrier event but the carrier state wasn't changed. 612 * Use in drivers when querying carrier state asynchronously, to avoid missing 613 * events (link flaps) if link recovers before it's queried. 614 */ 615 void netif_carrier_event(struct net_device *dev) 616 { 617 if (dev->reg_state == NETREG_UNINITIALIZED) 618 return; 619 atomic_inc(&dev->carrier_up_count); 620 atomic_inc(&dev->carrier_down_count); 621 linkwatch_fire_event(dev); 622 } 623 EXPORT_SYMBOL_GPL(netif_carrier_event); 624 625 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces 626 under all circumstances. It is difficult to invent anything faster or 627 cheaper. 628 */ 629 630 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc, 631 struct sk_buff **to_free) 632 { 633 __qdisc_drop(skb, to_free); 634 return NET_XMIT_CN; 635 } 636 637 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc) 638 { 639 return NULL; 640 } 641 642 struct Qdisc_ops noop_qdisc_ops __read_mostly = { 643 .id = "noop", 644 .priv_size = 0, 645 .enqueue = noop_enqueue, 646 .dequeue = noop_dequeue, 647 .peek = noop_dequeue, 648 .owner = THIS_MODULE, 649 }; 650 651 static struct netdev_queue noop_netdev_queue = { 652 RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc), 653 RCU_POINTER_INITIALIZER(qdisc_sleeping, &noop_qdisc), 654 }; 655 656 struct Qdisc noop_qdisc = { 657 .enqueue = noop_enqueue, 658 .dequeue = noop_dequeue, 659 .flags = TCQ_F_BUILTIN, 660 .ops = &noop_qdisc_ops, 661 .q.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock), 662 .dev_queue = &noop_netdev_queue, 663 .busylock = __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock), 664 .gso_skb = { 665 .next = (struct sk_buff *)&noop_qdisc.gso_skb, 666 .prev = (struct sk_buff *)&noop_qdisc.gso_skb, 667 .qlen = 0, 668 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock), 669 }, 670 .skb_bad_txq = { 671 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq, 672 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq, 673 .qlen = 0, 674 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock), 675 }, 676 }; 677 EXPORT_SYMBOL(noop_qdisc); 678 679 static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt, 680 struct netlink_ext_ack *extack) 681 { 682 /* register_qdisc() assigns a default of noop_enqueue if unset, 683 * but __dev_queue_xmit() treats noqueue only as such 684 * if this is NULL - so clear it here. */ 685 qdisc->enqueue = NULL; 686 return 0; 687 } 688 689 struct Qdisc_ops noqueue_qdisc_ops __read_mostly = { 690 .id = "noqueue", 691 .priv_size = 0, 692 .init = noqueue_init, 693 .enqueue = noop_enqueue, 694 .dequeue = noop_dequeue, 695 .peek = noop_dequeue, 696 .owner = THIS_MODULE, 697 }; 698 699 const u8 sch_default_prio2band[TC_PRIO_MAX + 1] = { 700 1, 2, 2, 2, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1 701 }; 702 EXPORT_SYMBOL(sch_default_prio2band); 703 704 /* 3-band FIFO queue: old style, but should be a bit faster than 705 generic prio+fifo combination. 706 */ 707 708 #define PFIFO_FAST_BANDS 3 709 710 /* 711 * Private data for a pfifo_fast scheduler containing: 712 * - rings for priority bands 713 */ 714 struct pfifo_fast_priv { 715 struct skb_array q[PFIFO_FAST_BANDS]; 716 }; 717 718 static inline struct skb_array *band2list(struct pfifo_fast_priv *priv, 719 int band) 720 { 721 return &priv->q[band]; 722 } 723 724 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc, 725 struct sk_buff **to_free) 726 { 727 int band = sch_default_prio2band[skb->priority & TC_PRIO_MAX]; 728 struct pfifo_fast_priv *priv = qdisc_priv(qdisc); 729 struct skb_array *q = band2list(priv, band); 730 unsigned int pkt_len = qdisc_pkt_len(skb); 731 int err; 732 733 err = skb_array_produce(q, skb); 734 735 if (unlikely(err)) { 736 if (qdisc_is_percpu_stats(qdisc)) 737 return qdisc_drop_cpu(skb, qdisc, to_free); 738 else 739 return qdisc_drop(skb, qdisc, to_free); 740 } 741 742 qdisc_update_stats_at_enqueue(qdisc, pkt_len); 743 return NET_XMIT_SUCCESS; 744 } 745 746 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc) 747 { 748 struct pfifo_fast_priv *priv = qdisc_priv(qdisc); 749 struct sk_buff *skb = NULL; 750 bool need_retry = true; 751 int band; 752 753 retry: 754 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) { 755 struct skb_array *q = band2list(priv, band); 756 757 if (__skb_array_empty(q)) 758 continue; 759 760 skb = __skb_array_consume(q); 761 } 762 if (likely(skb)) { 763 qdisc_update_stats_at_dequeue(qdisc, skb); 764 } else if (need_retry && 765 READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY) { 766 /* Delay clearing the STATE_MISSED here to reduce 767 * the overhead of the second spin_trylock() in 768 * qdisc_run_begin() and __netif_schedule() calling 769 * in qdisc_run_end(). 770 */ 771 clear_bit(__QDISC_STATE_MISSED, &qdisc->state); 772 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state); 773 774 /* Make sure dequeuing happens after clearing 775 * STATE_MISSED. 776 */ 777 smp_mb__after_atomic(); 778 779 need_retry = false; 780 781 goto retry; 782 } 783 784 return skb; 785 } 786 787 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc) 788 { 789 struct pfifo_fast_priv *priv = qdisc_priv(qdisc); 790 struct sk_buff *skb = NULL; 791 int band; 792 793 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) { 794 struct skb_array *q = band2list(priv, band); 795 796 skb = __skb_array_peek(q); 797 } 798 799 return skb; 800 } 801 802 static void pfifo_fast_reset(struct Qdisc *qdisc) 803 { 804 int i, band; 805 struct pfifo_fast_priv *priv = qdisc_priv(qdisc); 806 807 for (band = 0; band < PFIFO_FAST_BANDS; band++) { 808 struct skb_array *q = band2list(priv, band); 809 struct sk_buff *skb; 810 811 /* NULL ring is possible if destroy path is due to a failed 812 * skb_array_init() in pfifo_fast_init() case. 813 */ 814 if (!q->ring.queue) 815 continue; 816 817 while ((skb = __skb_array_consume(q)) != NULL) 818 kfree_skb(skb); 819 } 820 821 if (qdisc_is_percpu_stats(qdisc)) { 822 for_each_possible_cpu(i) { 823 struct gnet_stats_queue *q; 824 825 q = per_cpu_ptr(qdisc->cpu_qstats, i); 826 q->backlog = 0; 827 q->qlen = 0; 828 } 829 } 830 } 831 832 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb) 833 { 834 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS }; 835 836 memcpy(&opt.priomap, sch_default_prio2band, TC_PRIO_MAX + 1); 837 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt)) 838 goto nla_put_failure; 839 return skb->len; 840 841 nla_put_failure: 842 return -1; 843 } 844 845 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt, 846 struct netlink_ext_ack *extack) 847 { 848 unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len; 849 struct pfifo_fast_priv *priv = qdisc_priv(qdisc); 850 int prio; 851 852 /* guard against zero length rings */ 853 if (!qlen) 854 return -EINVAL; 855 856 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { 857 struct skb_array *q = band2list(priv, prio); 858 int err; 859 860 err = skb_array_init(q, qlen, GFP_KERNEL); 861 if (err) 862 return -ENOMEM; 863 } 864 865 /* Can by-pass the queue discipline */ 866 qdisc->flags |= TCQ_F_CAN_BYPASS; 867 return 0; 868 } 869 870 static void pfifo_fast_destroy(struct Qdisc *sch) 871 { 872 struct pfifo_fast_priv *priv = qdisc_priv(sch); 873 int prio; 874 875 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { 876 struct skb_array *q = band2list(priv, prio); 877 878 /* NULL ring is possible if destroy path is due to a failed 879 * skb_array_init() in pfifo_fast_init() case. 880 */ 881 if (!q->ring.queue) 882 continue; 883 /* Destroy ring but no need to kfree_skb because a call to 884 * pfifo_fast_reset() has already done that work. 885 */ 886 ptr_ring_cleanup(&q->ring, NULL); 887 } 888 } 889 890 static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch, 891 unsigned int new_len) 892 { 893 struct pfifo_fast_priv *priv = qdisc_priv(sch); 894 struct skb_array *bands[PFIFO_FAST_BANDS]; 895 int prio; 896 897 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { 898 struct skb_array *q = band2list(priv, prio); 899 900 bands[prio] = q; 901 } 902 903 return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len, 904 GFP_KERNEL); 905 } 906 907 struct Qdisc_ops pfifo_fast_ops __read_mostly = { 908 .id = "pfifo_fast", 909 .priv_size = sizeof(struct pfifo_fast_priv), 910 .enqueue = pfifo_fast_enqueue, 911 .dequeue = pfifo_fast_dequeue, 912 .peek = pfifo_fast_peek, 913 .init = pfifo_fast_init, 914 .destroy = pfifo_fast_destroy, 915 .reset = pfifo_fast_reset, 916 .dump = pfifo_fast_dump, 917 .change_tx_queue_len = pfifo_fast_change_tx_queue_len, 918 .owner = THIS_MODULE, 919 .static_flags = TCQ_F_NOLOCK | TCQ_F_CPUSTATS, 920 }; 921 EXPORT_SYMBOL(pfifo_fast_ops); 922 923 static struct lock_class_key qdisc_tx_busylock; 924 925 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, 926 const struct Qdisc_ops *ops, 927 struct netlink_ext_ack *extack) 928 { 929 struct Qdisc *sch; 930 unsigned int size = sizeof(*sch) + ops->priv_size; 931 int err = -ENOBUFS; 932 struct net_device *dev; 933 934 if (!dev_queue) { 935 NL_SET_ERR_MSG(extack, "No device queue given"); 936 err = -EINVAL; 937 goto errout; 938 } 939 940 dev = dev_queue->dev; 941 sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue)); 942 943 if (!sch) 944 goto errout; 945 __skb_queue_head_init(&sch->gso_skb); 946 __skb_queue_head_init(&sch->skb_bad_txq); 947 gnet_stats_basic_sync_init(&sch->bstats); 948 lockdep_register_key(&sch->root_lock_key); 949 spin_lock_init(&sch->q.lock); 950 lockdep_set_class(&sch->q.lock, &sch->root_lock_key); 951 952 if (ops->static_flags & TCQ_F_CPUSTATS) { 953 sch->cpu_bstats = 954 netdev_alloc_pcpu_stats(struct gnet_stats_basic_sync); 955 if (!sch->cpu_bstats) 956 goto errout1; 957 958 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue); 959 if (!sch->cpu_qstats) { 960 free_percpu(sch->cpu_bstats); 961 goto errout1; 962 } 963 } 964 965 spin_lock_init(&sch->busylock); 966 lockdep_set_class(&sch->busylock, 967 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); 968 969 /* seqlock has the same scope of busylock, for NOLOCK qdisc */ 970 spin_lock_init(&sch->seqlock); 971 lockdep_set_class(&sch->seqlock, 972 dev->qdisc_tx_busylock ?: &qdisc_tx_busylock); 973 974 sch->ops = ops; 975 sch->flags = ops->static_flags; 976 sch->enqueue = ops->enqueue; 977 sch->dequeue = ops->dequeue; 978 sch->dev_queue = dev_queue; 979 sch->owner = -1; 980 netdev_hold(dev, &sch->dev_tracker, GFP_KERNEL); 981 refcount_set(&sch->refcnt, 1); 982 983 return sch; 984 errout1: 985 lockdep_unregister_key(&sch->root_lock_key); 986 kfree(sch); 987 errout: 988 return ERR_PTR(err); 989 } 990 991 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue, 992 const struct Qdisc_ops *ops, 993 unsigned int parentid, 994 struct netlink_ext_ack *extack) 995 { 996 struct Qdisc *sch; 997 998 if (!try_module_get(ops->owner)) { 999 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter"); 1000 return NULL; 1001 } 1002 1003 sch = qdisc_alloc(dev_queue, ops, extack); 1004 if (IS_ERR(sch)) { 1005 module_put(ops->owner); 1006 return NULL; 1007 } 1008 sch->parent = parentid; 1009 1010 if (!ops->init || ops->init(sch, NULL, extack) == 0) { 1011 trace_qdisc_create(ops, dev_queue->dev, parentid); 1012 return sch; 1013 } 1014 1015 qdisc_put(sch); 1016 return NULL; 1017 } 1018 EXPORT_SYMBOL(qdisc_create_dflt); 1019 1020 /* Under qdisc_lock(qdisc) and BH! */ 1021 1022 void qdisc_reset(struct Qdisc *qdisc) 1023 { 1024 const struct Qdisc_ops *ops = qdisc->ops; 1025 1026 trace_qdisc_reset(qdisc); 1027 1028 if (ops->reset) 1029 ops->reset(qdisc); 1030 1031 __skb_queue_purge(&qdisc->gso_skb); 1032 __skb_queue_purge(&qdisc->skb_bad_txq); 1033 1034 qdisc->q.qlen = 0; 1035 qdisc->qstats.backlog = 0; 1036 } 1037 EXPORT_SYMBOL(qdisc_reset); 1038 1039 void qdisc_free(struct Qdisc *qdisc) 1040 { 1041 if (qdisc_is_percpu_stats(qdisc)) { 1042 free_percpu(qdisc->cpu_bstats); 1043 free_percpu(qdisc->cpu_qstats); 1044 } 1045 1046 kfree(qdisc); 1047 } 1048 1049 static void qdisc_free_cb(struct rcu_head *head) 1050 { 1051 struct Qdisc *q = container_of(head, struct Qdisc, rcu); 1052 1053 qdisc_free(q); 1054 } 1055 1056 static void __qdisc_destroy(struct Qdisc *qdisc) 1057 { 1058 const struct Qdisc_ops *ops = qdisc->ops; 1059 struct net_device *dev = qdisc_dev(qdisc); 1060 1061 #ifdef CONFIG_NET_SCHED 1062 qdisc_hash_del(qdisc); 1063 1064 qdisc_put_stab(rtnl_dereference(qdisc->stab)); 1065 #endif 1066 gen_kill_estimator(&qdisc->rate_est); 1067 1068 qdisc_reset(qdisc); 1069 1070 1071 if (ops->destroy) 1072 ops->destroy(qdisc); 1073 1074 lockdep_unregister_key(&qdisc->root_lock_key); 1075 module_put(ops->owner); 1076 netdev_put(dev, &qdisc->dev_tracker); 1077 1078 trace_qdisc_destroy(qdisc); 1079 1080 call_rcu(&qdisc->rcu, qdisc_free_cb); 1081 } 1082 1083 void qdisc_destroy(struct Qdisc *qdisc) 1084 { 1085 if (qdisc->flags & TCQ_F_BUILTIN) 1086 return; 1087 1088 __qdisc_destroy(qdisc); 1089 } 1090 1091 void qdisc_put(struct Qdisc *qdisc) 1092 { 1093 if (!qdisc) 1094 return; 1095 1096 if (qdisc->flags & TCQ_F_BUILTIN || 1097 !refcount_dec_and_test(&qdisc->refcnt)) 1098 return; 1099 1100 __qdisc_destroy(qdisc); 1101 } 1102 EXPORT_SYMBOL(qdisc_put); 1103 1104 /* Version of qdisc_put() that is called with rtnl mutex unlocked. 1105 * Intended to be used as optimization, this function only takes rtnl lock if 1106 * qdisc reference counter reached zero. 1107 */ 1108 1109 void qdisc_put_unlocked(struct Qdisc *qdisc) 1110 { 1111 if (qdisc->flags & TCQ_F_BUILTIN || 1112 !refcount_dec_and_rtnl_lock(&qdisc->refcnt)) 1113 return; 1114 1115 __qdisc_destroy(qdisc); 1116 rtnl_unlock(); 1117 } 1118 EXPORT_SYMBOL(qdisc_put_unlocked); 1119 1120 /* Attach toplevel qdisc to device queue. */ 1121 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue, 1122 struct Qdisc *qdisc) 1123 { 1124 struct Qdisc *oqdisc = rtnl_dereference(dev_queue->qdisc_sleeping); 1125 spinlock_t *root_lock; 1126 1127 root_lock = qdisc_lock(oqdisc); 1128 spin_lock_bh(root_lock); 1129 1130 /* ... and graft new one */ 1131 if (qdisc == NULL) 1132 qdisc = &noop_qdisc; 1133 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc); 1134 rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc); 1135 1136 spin_unlock_bh(root_lock); 1137 1138 return oqdisc; 1139 } 1140 EXPORT_SYMBOL(dev_graft_qdisc); 1141 1142 static void shutdown_scheduler_queue(struct net_device *dev, 1143 struct netdev_queue *dev_queue, 1144 void *_qdisc_default) 1145 { 1146 struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc_sleeping); 1147 struct Qdisc *qdisc_default = _qdisc_default; 1148 1149 if (qdisc) { 1150 rcu_assign_pointer(dev_queue->qdisc, qdisc_default); 1151 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc_default); 1152 1153 qdisc_put(qdisc); 1154 } 1155 } 1156 1157 static void attach_one_default_qdisc(struct net_device *dev, 1158 struct netdev_queue *dev_queue, 1159 void *_unused) 1160 { 1161 struct Qdisc *qdisc; 1162 const struct Qdisc_ops *ops = default_qdisc_ops; 1163 1164 if (dev->priv_flags & IFF_NO_QUEUE) 1165 ops = &noqueue_qdisc_ops; 1166 else if(dev->type == ARPHRD_CAN) 1167 ops = &pfifo_fast_ops; 1168 1169 qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL); 1170 if (!qdisc) 1171 return; 1172 1173 if (!netif_is_multiqueue(dev)) 1174 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; 1175 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc); 1176 } 1177 1178 static void attach_default_qdiscs(struct net_device *dev) 1179 { 1180 struct netdev_queue *txq; 1181 struct Qdisc *qdisc; 1182 1183 txq = netdev_get_tx_queue(dev, 0); 1184 1185 if (!netif_is_multiqueue(dev) || 1186 dev->priv_flags & IFF_NO_QUEUE) { 1187 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL); 1188 qdisc = rtnl_dereference(txq->qdisc_sleeping); 1189 rcu_assign_pointer(dev->qdisc, qdisc); 1190 qdisc_refcount_inc(qdisc); 1191 } else { 1192 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL); 1193 if (qdisc) { 1194 rcu_assign_pointer(dev->qdisc, qdisc); 1195 qdisc->ops->attach(qdisc); 1196 } 1197 } 1198 qdisc = rtnl_dereference(dev->qdisc); 1199 1200 /* Detect default qdisc setup/init failed and fallback to "noqueue" */ 1201 if (qdisc == &noop_qdisc) { 1202 netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n", 1203 default_qdisc_ops->id, noqueue_qdisc_ops.id); 1204 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc); 1205 dev->priv_flags |= IFF_NO_QUEUE; 1206 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL); 1207 qdisc = rtnl_dereference(txq->qdisc_sleeping); 1208 rcu_assign_pointer(dev->qdisc, qdisc); 1209 qdisc_refcount_inc(qdisc); 1210 dev->priv_flags ^= IFF_NO_QUEUE; 1211 } 1212 1213 #ifdef CONFIG_NET_SCHED 1214 if (qdisc != &noop_qdisc) 1215 qdisc_hash_add(qdisc, false); 1216 #endif 1217 } 1218 1219 static void transition_one_qdisc(struct net_device *dev, 1220 struct netdev_queue *dev_queue, 1221 void *_need_watchdog) 1222 { 1223 struct Qdisc *new_qdisc = rtnl_dereference(dev_queue->qdisc_sleeping); 1224 int *need_watchdog_p = _need_watchdog; 1225 1226 if (!(new_qdisc->flags & TCQ_F_BUILTIN)) 1227 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state); 1228 1229 rcu_assign_pointer(dev_queue->qdisc, new_qdisc); 1230 if (need_watchdog_p) { 1231 WRITE_ONCE(dev_queue->trans_start, 0); 1232 *need_watchdog_p = 1; 1233 } 1234 } 1235 1236 void dev_activate(struct net_device *dev) 1237 { 1238 int need_watchdog; 1239 1240 /* No queueing discipline is attached to device; 1241 * create default one for devices, which need queueing 1242 * and noqueue_qdisc for virtual interfaces 1243 */ 1244 1245 if (rtnl_dereference(dev->qdisc) == &noop_qdisc) 1246 attach_default_qdiscs(dev); 1247 1248 if (!netif_carrier_ok(dev)) 1249 /* Delay activation until next carrier-on event */ 1250 return; 1251 1252 need_watchdog = 0; 1253 netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog); 1254 if (dev_ingress_queue(dev)) 1255 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL); 1256 1257 if (need_watchdog) { 1258 netif_trans_update(dev); 1259 dev_watchdog_up(dev); 1260 } 1261 } 1262 EXPORT_SYMBOL(dev_activate); 1263 1264 static void qdisc_deactivate(struct Qdisc *qdisc) 1265 { 1266 if (qdisc->flags & TCQ_F_BUILTIN) 1267 return; 1268 1269 set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state); 1270 } 1271 1272 static void dev_deactivate_queue(struct net_device *dev, 1273 struct netdev_queue *dev_queue, 1274 void *_qdisc_default) 1275 { 1276 struct Qdisc *qdisc_default = _qdisc_default; 1277 struct Qdisc *qdisc; 1278 1279 qdisc = rtnl_dereference(dev_queue->qdisc); 1280 if (qdisc) { 1281 qdisc_deactivate(qdisc); 1282 rcu_assign_pointer(dev_queue->qdisc, qdisc_default); 1283 } 1284 } 1285 1286 static void dev_reset_queue(struct net_device *dev, 1287 struct netdev_queue *dev_queue, 1288 void *_unused) 1289 { 1290 struct Qdisc *qdisc; 1291 bool nolock; 1292 1293 qdisc = rtnl_dereference(dev_queue->qdisc_sleeping); 1294 if (!qdisc) 1295 return; 1296 1297 nolock = qdisc->flags & TCQ_F_NOLOCK; 1298 1299 if (nolock) 1300 spin_lock_bh(&qdisc->seqlock); 1301 spin_lock_bh(qdisc_lock(qdisc)); 1302 1303 qdisc_reset(qdisc); 1304 1305 spin_unlock_bh(qdisc_lock(qdisc)); 1306 if (nolock) { 1307 clear_bit(__QDISC_STATE_MISSED, &qdisc->state); 1308 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state); 1309 spin_unlock_bh(&qdisc->seqlock); 1310 } 1311 } 1312 1313 static bool some_qdisc_is_busy(struct net_device *dev) 1314 { 1315 unsigned int i; 1316 1317 for (i = 0; i < dev->num_tx_queues; i++) { 1318 struct netdev_queue *dev_queue; 1319 spinlock_t *root_lock; 1320 struct Qdisc *q; 1321 int val; 1322 1323 dev_queue = netdev_get_tx_queue(dev, i); 1324 q = rtnl_dereference(dev_queue->qdisc_sleeping); 1325 1326 root_lock = qdisc_lock(q); 1327 spin_lock_bh(root_lock); 1328 1329 val = (qdisc_is_running(q) || 1330 test_bit(__QDISC_STATE_SCHED, &q->state)); 1331 1332 spin_unlock_bh(root_lock); 1333 1334 if (val) 1335 return true; 1336 } 1337 return false; 1338 } 1339 1340 /** 1341 * dev_deactivate_many - deactivate transmissions on several devices 1342 * @head: list of devices to deactivate 1343 * 1344 * This function returns only when all outstanding transmissions 1345 * have completed, unless all devices are in dismantle phase. 1346 */ 1347 void dev_deactivate_many(struct list_head *head) 1348 { 1349 struct net_device *dev; 1350 1351 list_for_each_entry(dev, head, close_list) { 1352 netdev_for_each_tx_queue(dev, dev_deactivate_queue, 1353 &noop_qdisc); 1354 if (dev_ingress_queue(dev)) 1355 dev_deactivate_queue(dev, dev_ingress_queue(dev), 1356 &noop_qdisc); 1357 1358 dev_watchdog_down(dev); 1359 } 1360 1361 /* Wait for outstanding qdisc-less dev_queue_xmit calls or 1362 * outstanding qdisc enqueuing calls. 1363 * This is avoided if all devices are in dismantle phase : 1364 * Caller will call synchronize_net() for us 1365 */ 1366 synchronize_net(); 1367 1368 list_for_each_entry(dev, head, close_list) { 1369 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL); 1370 1371 if (dev_ingress_queue(dev)) 1372 dev_reset_queue(dev, dev_ingress_queue(dev), NULL); 1373 } 1374 1375 /* Wait for outstanding qdisc_run calls. */ 1376 list_for_each_entry(dev, head, close_list) { 1377 while (some_qdisc_is_busy(dev)) { 1378 /* wait_event() would avoid this sleep-loop but would 1379 * require expensive checks in the fast paths of packet 1380 * processing which isn't worth it. 1381 */ 1382 schedule_timeout_uninterruptible(1); 1383 } 1384 } 1385 } 1386 1387 void dev_deactivate(struct net_device *dev) 1388 { 1389 LIST_HEAD(single); 1390 1391 list_add(&dev->close_list, &single); 1392 dev_deactivate_many(&single); 1393 list_del(&single); 1394 } 1395 EXPORT_SYMBOL(dev_deactivate); 1396 1397 static int qdisc_change_tx_queue_len(struct net_device *dev, 1398 struct netdev_queue *dev_queue) 1399 { 1400 struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc_sleeping); 1401 const struct Qdisc_ops *ops = qdisc->ops; 1402 1403 if (ops->change_tx_queue_len) 1404 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len); 1405 return 0; 1406 } 1407 1408 void dev_qdisc_change_real_num_tx(struct net_device *dev, 1409 unsigned int new_real_tx) 1410 { 1411 struct Qdisc *qdisc = rtnl_dereference(dev->qdisc); 1412 1413 if (qdisc->ops->change_real_num_tx) 1414 qdisc->ops->change_real_num_tx(qdisc, new_real_tx); 1415 } 1416 1417 void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx) 1418 { 1419 #ifdef CONFIG_NET_SCHED 1420 struct net_device *dev = qdisc_dev(sch); 1421 struct Qdisc *qdisc; 1422 unsigned int i; 1423 1424 for (i = new_real_tx; i < dev->real_num_tx_queues; i++) { 1425 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc_sleeping); 1426 /* Only update the default qdiscs we created, 1427 * qdiscs with handles are always hashed. 1428 */ 1429 if (qdisc != &noop_qdisc && !qdisc->handle) 1430 qdisc_hash_del(qdisc); 1431 } 1432 for (i = dev->real_num_tx_queues; i < new_real_tx; i++) { 1433 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc_sleeping); 1434 if (qdisc != &noop_qdisc && !qdisc->handle) 1435 qdisc_hash_add(qdisc, false); 1436 } 1437 #endif 1438 } 1439 EXPORT_SYMBOL(mq_change_real_num_tx); 1440 1441 int dev_qdisc_change_tx_queue_len(struct net_device *dev) 1442 { 1443 bool up = dev->flags & IFF_UP; 1444 unsigned int i; 1445 int ret = 0; 1446 1447 if (up) 1448 dev_deactivate(dev); 1449 1450 for (i = 0; i < dev->num_tx_queues; i++) { 1451 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]); 1452 1453 /* TODO: revert changes on a partial failure */ 1454 if (ret) 1455 break; 1456 } 1457 1458 if (up) 1459 dev_activate(dev); 1460 return ret; 1461 } 1462 1463 static void dev_init_scheduler_queue(struct net_device *dev, 1464 struct netdev_queue *dev_queue, 1465 void *_qdisc) 1466 { 1467 struct Qdisc *qdisc = _qdisc; 1468 1469 rcu_assign_pointer(dev_queue->qdisc, qdisc); 1470 rcu_assign_pointer(dev_queue->qdisc_sleeping, qdisc); 1471 } 1472 1473 void dev_init_scheduler(struct net_device *dev) 1474 { 1475 rcu_assign_pointer(dev->qdisc, &noop_qdisc); 1476 netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc); 1477 if (dev_ingress_queue(dev)) 1478 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc); 1479 1480 timer_setup(&dev->watchdog_timer, dev_watchdog, 0); 1481 } 1482 1483 void dev_shutdown(struct net_device *dev) 1484 { 1485 netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc); 1486 if (dev_ingress_queue(dev)) 1487 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc); 1488 qdisc_put(rtnl_dereference(dev->qdisc)); 1489 rcu_assign_pointer(dev->qdisc, &noop_qdisc); 1490 1491 WARN_ON(timer_pending(&dev->watchdog_timer)); 1492 } 1493 1494 /** 1495 * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division 1496 * @rate: Rate to compute reciprocal division values of 1497 * @mult: Multiplier for reciprocal division 1498 * @shift: Shift for reciprocal division 1499 * 1500 * The multiplier and shift for reciprocal division by rate are stored 1501 * in mult and shift. 1502 * 1503 * The deal here is to replace a divide by a reciprocal one 1504 * in fast path (a reciprocal divide is a multiply and a shift) 1505 * 1506 * Normal formula would be : 1507 * time_in_ns = (NSEC_PER_SEC * len) / rate_bps 1508 * 1509 * We compute mult/shift to use instead : 1510 * time_in_ns = (len * mult) >> shift; 1511 * 1512 * We try to get the highest possible mult value for accuracy, 1513 * but have to make sure no overflows will ever happen. 1514 * 1515 * reciprocal_value() is not used here it doesn't handle 64-bit values. 1516 */ 1517 static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift) 1518 { 1519 u64 factor = NSEC_PER_SEC; 1520 1521 *mult = 1; 1522 *shift = 0; 1523 1524 if (rate <= 0) 1525 return; 1526 1527 for (;;) { 1528 *mult = div64_u64(factor, rate); 1529 if (*mult & (1U << 31) || factor & (1ULL << 63)) 1530 break; 1531 factor <<= 1; 1532 (*shift)++; 1533 } 1534 } 1535 1536 void psched_ratecfg_precompute(struct psched_ratecfg *r, 1537 const struct tc_ratespec *conf, 1538 u64 rate64) 1539 { 1540 memset(r, 0, sizeof(*r)); 1541 r->overhead = conf->overhead; 1542 r->mpu = conf->mpu; 1543 r->rate_bytes_ps = max_t(u64, conf->rate, rate64); 1544 r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK); 1545 psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift); 1546 } 1547 EXPORT_SYMBOL(psched_ratecfg_precompute); 1548 1549 void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64) 1550 { 1551 r->rate_pkts_ps = pktrate64; 1552 psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift); 1553 } 1554 EXPORT_SYMBOL(psched_ppscfg_precompute); 1555 1556 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp, 1557 struct tcf_proto *tp_head) 1558 { 1559 /* Protected with chain0->filter_chain_lock. 1560 * Can't access chain directly because tp_head can be NULL. 1561 */ 1562 struct mini_Qdisc *miniq_old = 1563 rcu_dereference_protected(*miniqp->p_miniq, 1); 1564 struct mini_Qdisc *miniq; 1565 1566 if (!tp_head) { 1567 RCU_INIT_POINTER(*miniqp->p_miniq, NULL); 1568 } else { 1569 miniq = miniq_old != &miniqp->miniq1 ? 1570 &miniqp->miniq1 : &miniqp->miniq2; 1571 1572 /* We need to make sure that readers won't see the miniq 1573 * we are about to modify. So ensure that at least one RCU 1574 * grace period has elapsed since the miniq was made 1575 * inactive. 1576 */ 1577 if (IS_ENABLED(CONFIG_PREEMPT_RT)) 1578 cond_synchronize_rcu(miniq->rcu_state); 1579 else if (!poll_state_synchronize_rcu(miniq->rcu_state)) 1580 synchronize_rcu_expedited(); 1581 1582 miniq->filter_list = tp_head; 1583 rcu_assign_pointer(*miniqp->p_miniq, miniq); 1584 } 1585 1586 if (miniq_old) 1587 /* This is counterpart of the rcu sync above. We need to 1588 * block potential new user of miniq_old until all readers 1589 * are not seeing it. 1590 */ 1591 miniq_old->rcu_state = start_poll_synchronize_rcu(); 1592 } 1593 EXPORT_SYMBOL(mini_qdisc_pair_swap); 1594 1595 void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp, 1596 struct tcf_block *block) 1597 { 1598 miniqp->miniq1.block = block; 1599 miniqp->miniq2.block = block; 1600 } 1601 EXPORT_SYMBOL(mini_qdisc_pair_block_init); 1602 1603 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc, 1604 struct mini_Qdisc __rcu **p_miniq) 1605 { 1606 miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats; 1607 miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats; 1608 miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats; 1609 miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats; 1610 miniqp->miniq1.rcu_state = get_state_synchronize_rcu(); 1611 miniqp->miniq2.rcu_state = miniqp->miniq1.rcu_state; 1612 miniqp->p_miniq = p_miniq; 1613 } 1614 EXPORT_SYMBOL(mini_qdisc_pair_init); 1615