net/sched/sch_generic.c

   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, <[email protected]>
   6  *              Jamal Hadi Salim, <[email protected]> 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 <trace/events/qdisc.h>
  31 #include <trace/events/net.h>
  32 #include <net/xfrm.h>
  33
  34 /* Qdisc to use by default */
  35 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
  36 EXPORT_SYMBOL(default_qdisc_ops);
  37
  38 static void qdisc_maybe_clear_missed(struct Qdisc *q,
  39                                      const struct netdev_queue *txq)
  40 {
  41         clear_bit(__QDISC_STATE_MISSED, &q->state);
  42
  43         /* Make sure the below netif_xmit_frozen_or_stopped()
  44          * checking happens after clearing STATE_MISSED.
  45          */
  46         smp_mb__after_atomic();
  47
  48         /* Checking netif_xmit_frozen_or_stopped() again to
  49          * make sure STATE_MISSED is set if the STATE_MISSED
  50          * set by netif_tx_wake_queue()'s rescheduling of
  51          * net_tx_action() is cleared by the above clear_bit().
  52          */
  53         if (!netif_xmit_frozen_or_stopped(txq))
  54                 set_bit(__QDISC_STATE_MISSED, &q->state);
  55         else
  56                 set_bit(__QDISC_STATE_DRAINING, &q->state);
  57 }
  58
  59 /* Main transmission queue. */
  60
  61 /* Modifications to data participating in scheduling must be protected with
  62  * qdisc_lock(qdisc) spinlock.
  63  *
  64  * The idea is the following:
  65  * - enqueue, dequeue are serialized via qdisc root lock
  66  * - ingress filtering is also serialized via qdisc root lock
  67  * - updates to tree and tree walking are only done under the rtnl mutex.
  68  */
  69
  70 #define SKB_XOFF_MAGIC ((struct sk_buff *)1UL)
  71
  72 static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
  73 {
  74         const struct netdev_queue *txq = q->dev_queue;
  75         spinlock_t *lock = NULL;
  76         struct sk_buff *skb;
  77
  78         if (q->flags & TCQ_F_NOLOCK) {
  79                 lock = qdisc_lock(q);
  80                 spin_lock(lock);
  81         }
  82
  83         skb = skb_peek(&q->skb_bad_txq);
  84         if (skb) {
  85                 /* check the reason of requeuing without tx lock first */
  86                 txq = skb_get_tx_queue(txq->dev, skb);
  87                 if (!netif_xmit_frozen_or_stopped(txq)) {
  88                         skb = __skb_dequeue(&q->skb_bad_txq);
  89                         if (qdisc_is_percpu_stats(q)) {
  90                                 qdisc_qstats_cpu_backlog_dec(q, skb);
  91                                 qdisc_qstats_cpu_qlen_dec(q);
  92                         } else {
  93                                 qdisc_qstats_backlog_dec(q, skb);
  94                                 q->q.qlen--;
  95                         }
  96                 } else {
  97                         skb = SKB_XOFF_MAGIC;
  98                         qdisc_maybe_clear_missed(q, txq);
  99                 }
 100         }
 101
 102         if (lock)
 103                 spin_unlock(lock);
 104
 105         return skb;
 106 }
 107
 108 static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
 109 {
 110         struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
 111
 112         if (unlikely(skb))
 113                 skb = __skb_dequeue_bad_txq(q);
 114
 115         return skb;
 116 }
 117
 118 static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
 119                                              struct sk_buff *skb)
 120 {
 121         spinlock_t *lock = NULL;
 122
 123         if (q->flags & TCQ_F_NOLOCK) {
 124                 lock = qdisc_lock(q);
 125                 spin_lock(lock);
 126         }
 127
 128         __skb_queue_tail(&q->skb_bad_txq, skb);
 129
 130         if (qdisc_is_percpu_stats(q)) {
 131                 qdisc_qstats_cpu_backlog_inc(q, skb);
 132                 qdisc_qstats_cpu_qlen_inc(q);
 133         } else {
 134                 qdisc_qstats_backlog_inc(q, skb);
 135                 q->q.qlen++;
 136         }
 137
 138         if (lock)
 139                 spin_unlock(lock);
 140 }
 141
 142 static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
 143 {
 144         spinlock_t *lock = NULL;
 145
 146         if (q->flags & TCQ_F_NOLOCK) {
 147                 lock = qdisc_lock(q);
 148                 spin_lock(lock);
 149         }
 150
 151         while (skb) {
 152                 struct sk_buff *next = skb->next;
 153
 154                 __skb_queue_tail(&q->gso_skb, skb);
 155
 156                 /* it's still part of the queue */
 157                 if (qdisc_is_percpu_stats(q)) {
 158                         qdisc_qstats_cpu_requeues_inc(q);
 159                         qdisc_qstats_cpu_backlog_inc(q, skb);
 160                         qdisc_qstats_cpu_qlen_inc(q);
 161                 } else {
 162                         q->qstats.requeues++;
 163                         qdisc_qstats_backlog_inc(q, skb);
 164                         q->q.qlen++;
 165                 }
 166
 167                 skb = next;
 168         }
 169
 170         if (lock) {
 171                 spin_unlock(lock);
 172                 set_bit(__QDISC_STATE_MISSED, &q->state);
 173         } else {
 174                 __netif_schedule(q);
 175         }
 176 }
 177
 178 static void try_bulk_dequeue_skb(struct Qdisc *q,
 179                                  struct sk_buff *skb,
 180                                  const struct netdev_queue *txq,
 181                                  int *packets)
 182 {
 183         int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
 184
 185         while (bytelimit > 0) {
 186                 struct sk_buff *nskb = q->dequeue(q);
 187
 188                 if (!nskb)
 189                         break;
 190
 191                 bytelimit -= nskb->len; /* covers GSO len */
 192                 skb->next = nskb;
 193                 skb = nskb;
 194                 (*packets)++; /* GSO counts as one pkt */
 195         }
 196         skb_mark_not_on_list(skb);
 197 }
 198
 199 /* This variant of try_bulk_dequeue_skb() makes sure
 200  * all skbs in the chain are for the same txq
 201  */
 202 static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
 203                                       struct sk_buff *skb,
 204                                       int *packets)
 205 {
 206         int mapping = skb_get_queue_mapping(skb);
 207         struct sk_buff *nskb;
 208         int cnt = 0;
 209
 210         do {
 211                 nskb = q->dequeue(q);
 212                 if (!nskb)
 213                         break;
 214                 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
 215                         qdisc_enqueue_skb_bad_txq(q, nskb);
 216                         break;
 217                 }
 218                 skb->next = nskb;
 219                 skb = nskb;
 220         } while (++cnt < 8);
 221         (*packets) += cnt;
 222         skb_mark_not_on_list(skb);
 223 }
 224
 225 /* Note that dequeue_skb can possibly return a SKB list (via skb->next).
 226  * A requeued skb (via q->gso_skb) can also be a SKB list.
 227  */
 228 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
 229                                    int *packets)
 230 {
 231         const struct netdev_queue *txq = q->dev_queue;
 232         struct sk_buff *skb = NULL;
 233
 234         *packets = 1;
 235         if (unlikely(!skb_queue_empty(&q->gso_skb))) {
 236                 spinlock_t *lock = NULL;
 237
 238                 if (q->flags & TCQ_F_NOLOCK) {
 239                         lock = qdisc_lock(q);
 240                         spin_lock(lock);
 241                 }
 242
 243                 skb = skb_peek(&q->gso_skb);
 244
 245                 /* skb may be null if another cpu pulls gso_skb off in between
 246                  * empty check and lock.
 247                  */
 248                 if (!skb) {
 249                         if (lock)
 250                                 spin_unlock(lock);
 251                         goto validate;
 252                 }
 253
 254                 /* skb in gso_skb were already validated */
 255                 *validate = false;
 256                 if (xfrm_offload(skb))
 257                         *validate = true;
 258                 /* check the reason of requeuing without tx lock first */
 259                 txq = skb_get_tx_queue(txq->dev, skb);
 260                 if (!netif_xmit_frozen_or_stopped(txq)) {
 261                         skb = __skb_dequeue(&q->gso_skb);
 262                         if (qdisc_is_percpu_stats(q)) {
 263                                 qdisc_qstats_cpu_backlog_dec(q, skb);
 264                                 qdisc_qstats_cpu_qlen_dec(q);
 265                         } else {
 266                                 qdisc_qstats_backlog_dec(q, skb);
 267                                 q->q.qlen--;
 268                         }
 269                 } else {
 270                         skb = NULL;
 271                         qdisc_maybe_clear_missed(q, txq);
 272                 }
 273                 if (lock)
 274                         spin_unlock(lock);
 275                 goto trace;
 276         }
 277 validate:
 278         *validate = true;
 279
 280         if ((q->flags & TCQ_F_ONETXQUEUE) &&
 281             netif_xmit_frozen_or_stopped(txq)) {
 282                 qdisc_maybe_clear_missed(q, txq);
 283                 return skb;
 284         }
 285
 286         skb = qdisc_dequeue_skb_bad_txq(q);
 287         if (unlikely(skb)) {
 288                 if (skb == SKB_XOFF_MAGIC)
 289                         return NULL;
 290                 goto bulk;
 291         }
 292         skb = q->dequeue(q);
 293         if (skb) {
 294 bulk:
 295                 if (qdisc_may_bulk(q))
 296                         try_bulk_dequeue_skb(q, skb, txq, packets);
 297                 else
 298                         try_bulk_dequeue_skb_slow(q, skb, packets);
 299         }
 300 trace:
 301         trace_qdisc_dequeue(q, txq, *packets, skb);
 302         return skb;
 303 }
 304
 305 /*
 306  * Transmit possibly several skbs, and handle the return status as
 307  * required. Owning qdisc running bit guarantees that only one CPU
 308  * can execute this function.
 309  *
 310  * Returns to the caller:
 311  *                              false  - hardware queue frozen backoff
 312  *                              true   - feel free to send more pkts
 313  */
 314 bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 315                      struct net_device *dev, struct netdev_queue *txq,
 316                      spinlock_t *root_lock, bool validate)
 317 {
 318         int ret = NETDEV_TX_BUSY;
 319         bool again = false;
 320
 321         /* And release qdisc */
 322         if (root_lock)
 323                 spin_unlock(root_lock);
 324
 325         /* Note that we validate skb (GSO, checksum, ...) outside of locks */
 326         if (validate)
 327                 skb = validate_xmit_skb_list(skb, dev, &again);
 328
 329 #ifdef CONFIG_XFRM_OFFLOAD
 330         if (unlikely(again)) {
 331                 if (root_lock)
 332                         spin_lock(root_lock);
 333
 334                 dev_requeue_skb(skb, q);
 335                 return false;
 336         }
 337 #endif
 338
 339         if (likely(skb)) {
 340                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 341                 if (!netif_xmit_frozen_or_stopped(txq))
 342                         skb = dev_hard_start_xmit(skb, dev, txq, &ret);
 343                 else
 344                         qdisc_maybe_clear_missed(q, txq);
 345
 346                 HARD_TX_UNLOCK(dev, txq);
 347         } else {
 348                 if (root_lock)
 349                         spin_lock(root_lock);
 350                 return true;
 351         }
 352
 353         if (root_lock)
 354                 spin_lock(root_lock);
 355
 356         if (!dev_xmit_complete(ret)) {
 357                 /* Driver returned NETDEV_TX_BUSY - requeue skb */
 358                 if (unlikely(ret != NETDEV_TX_BUSY))
 359                         net_warn_ratelimited("BUG %s code %d qlen %d\n",
 360                                              dev->name, ret, q->q.qlen);
 361
 362                 dev_requeue_skb(skb, q);
 363                 return false;
 364         }
 365
 366         return true;
 367 }
 368
 369 /*
 370  * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 371  *
 372  * running seqcount guarantees only one CPU can process
 373  * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 374  * this queue.
 375  *
 376  *  netif_tx_lock serializes accesses to device driver.
 377  *
 378  *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 379  *  if one is grabbed, another must be free.
 380  *
 381  * Note, that this procedure can be called by a watchdog timer
 382  *
 383  * Returns to the caller:
 384  *                              0  - queue is empty or throttled.
 385  *                              >0 - queue is not empty.
 386  *
 387  */
 388 static inline bool qdisc_restart(struct Qdisc *q, int *packets)
 389 {
 390         spinlock_t *root_lock = NULL;
 391         struct netdev_queue *txq;
 392         struct net_device *dev;
 393         struct sk_buff *skb;
 394         bool validate;
 395
 396         /* Dequeue packet */
 397         skb = dequeue_skb(q, &validate, packets);
 398         if (unlikely(!skb))
 399                 return false;
 400
 401         if (!(q->flags & TCQ_F_NOLOCK))
 402                 root_lock = qdisc_lock(q);
 403
 404         dev = qdisc_dev(q);
 405         txq = skb_get_tx_queue(dev, skb);
 406
 407         return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
 408 }
 409
 410 void __qdisc_run(struct Qdisc *q)
 411 {
 412         int quota = dev_tx_weight;
 413         int packets;
 414
 415         while (qdisc_restart(q, &packets)) {
 416                 quota -= packets;
 417                 if (quota <= 0) {
 418                         if (q->flags & TCQ_F_NOLOCK)
 419                                 set_bit(__QDISC_STATE_MISSED, &q->state);
 420                         else
 421                                 __netif_schedule(q);
 422
 423                         break;
 424                 }
 425         }
 426 }
 427
 428 unsigned long dev_trans_start(struct net_device *dev)
 429 {
 430         unsigned long val, res;
 431         unsigned int i;
 432
 433         if (is_vlan_dev(dev))
 434                 dev = vlan_dev_real_dev(dev);
 435         else if (netif_is_macvlan(dev))
 436                 dev = macvlan_dev_real_dev(dev);
 437         res = netdev_get_tx_queue(dev, 0)->trans_start;
 438         for (i = 1; i < dev->num_tx_queues; i++) {
 439                 val = netdev_get_tx_queue(dev, i)->trans_start;
 440                 if (val && time_after(val, res))
 441                         res = val;
 442         }
 443
 444         return res;
 445 }
 446 EXPORT_SYMBOL(dev_trans_start);
 447
 448 static void dev_watchdog(struct timer_list *t)
 449 {
 450         struct net_device *dev = from_timer(dev, t, watchdog_timer);
 451
 452         netif_tx_lock(dev);
 453         if (!qdisc_tx_is_noop(dev)) {
 454                 if (netif_device_present(dev) &&
 455                     netif_running(dev) &&
 456                     netif_carrier_ok(dev)) {
 457                         int some_queue_timedout = 0;
 458                         unsigned int i;
 459                         unsigned long trans_start;
 460
 461                         for (i = 0; i < dev->num_tx_queues; i++) {
 462                                 struct netdev_queue *txq;
 463
 464                                 txq = netdev_get_tx_queue(dev, i);
 465                                 trans_start = txq->trans_start;
 466                                 if (netif_xmit_stopped(txq) &&
 467                                     time_after(jiffies, (trans_start +
 468                                                          dev->watchdog_timeo))) {
 469                                         some_queue_timedout = 1;
 470                                         txq->trans_timeout++;
 471                                         break;
 472                                 }
 473                         }
 474
 475                         if (some_queue_timedout) {
 476                                 trace_net_dev_xmit_timeout(dev, i);
 477                                 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
 478                                        dev->name, netdev_drivername(dev), i);
 479                                 dev->netdev_ops->ndo_tx_timeout(dev, i);
 480                         }
 481                         if (!mod_timer(&dev->watchdog_timer,
 482                                        round_jiffies(jiffies +
 483                                                      dev->watchdog_timeo)))
 484                                 dev_hold(dev);
 485                 }
 486         }
 487         netif_tx_unlock(dev);
 488
 489         dev_put(dev);
 490 }
 491
 492 void __netdev_watchdog_up(struct net_device *dev)
 493 {
 494         if (dev->netdev_ops->ndo_tx_timeout) {
 495                 if (dev->watchdog_timeo <= 0)
 496                         dev->watchdog_timeo = 5*HZ;
 497                 if (!mod_timer(&dev->watchdog_timer,
 498                                round_jiffies(jiffies + dev->watchdog_timeo)))
 499                         dev_hold(dev);
 500         }
 501 }
 502 EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
 503
 504 static void dev_watchdog_up(struct net_device *dev)
 505 {
 506         __netdev_watchdog_up(dev);
 507 }
 508
 509 static void dev_watchdog_down(struct net_device *dev)
 510 {
 511         netif_tx_lock_bh(dev);
 512         if (del_timer(&dev->watchdog_timer))
 513                 dev_put(dev);
 514         netif_tx_unlock_bh(dev);
 515 }
 516
 517 /**
 518  *      netif_carrier_on - set carrier
 519  *      @dev: network device
 520  *
 521  * Device has detected acquisition of carrier.
 522  */
 523 void netif_carrier_on(struct net_device *dev)
 524 {
 525         if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
 526                 if (dev->reg_state == NETREG_UNINITIALIZED)
 527                         return;
 528                 atomic_inc(&dev->carrier_up_count);
 529                 linkwatch_fire_event(dev);
 530                 if (netif_running(dev))
 531                         __netdev_watchdog_up(dev);
 532         }
 533 }
 534 EXPORT_SYMBOL(netif_carrier_on);
 535
 536 /**
 537  *      netif_carrier_off - clear carrier
 538  *      @dev: network device
 539  *
 540  * Device has detected loss of carrier.
 541  */
 542 void netif_carrier_off(struct net_device *dev)
 543 {
 544         if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
 545                 if (dev->reg_state == NETREG_UNINITIALIZED)
 546                         return;
 547                 atomic_inc(&dev->carrier_down_count);
 548                 linkwatch_fire_event(dev);
 549         }
 550 }
 551 EXPORT_SYMBOL(netif_carrier_off);
 552
 553 /**
 554  *      netif_carrier_event - report carrier state event
 555  *      @dev: network device
 556  *
 557  * Device has detected a carrier event but the carrier state wasn't changed.
 558  * Use in drivers when querying carrier state asynchronously, to avoid missing
 559  * events (link flaps) if link recovers before it's queried.
 560  */
 561 void netif_carrier_event(struct net_device *dev)
 562 {
 563         if (dev->reg_state == NETREG_UNINITIALIZED)
 564                 return;
 565         atomic_inc(&dev->carrier_up_count);
 566         atomic_inc(&dev->carrier_down_count);
 567         linkwatch_fire_event(dev);
 568 }
 569 EXPORT_SYMBOL_GPL(netif_carrier_event);
 570
 571 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
 572    under all circumstances. It is difficult to invent anything faster or
 573    cheaper.
 574  */
 575
 576 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
 577                         struct sk_buff **to_free)
 578 {
 579         __qdisc_drop(skb, to_free);
 580         return NET_XMIT_CN;
 581 }
 582
 583 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
 584 {
 585         return NULL;
 586 }
 587
 588 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
 589         .id             =       "noop",
 590         .priv_size      =       0,
 591         .enqueue        =       noop_enqueue,
 592         .dequeue        =       noop_dequeue,
 593         .peek           =       noop_dequeue,
 594         .owner          =       THIS_MODULE,
 595 };
 596
 597 static struct netdev_queue noop_netdev_queue = {
 598         RCU_POINTER_INITIALIZER(qdisc, &noop_qdisc),
 599         .qdisc_sleeping =       &noop_qdisc,
 600 };
 601
 602 struct Qdisc noop_qdisc = {
 603         .enqueue        =       noop_enqueue,
 604         .dequeue        =       noop_dequeue,
 605         .flags          =       TCQ_F_BUILTIN,
 606         .ops            =       &noop_qdisc_ops,
 607         .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
 608         .dev_queue      =       &noop_netdev_queue,
 609         .busylock       =       __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
 610         .gso_skb = {
 611                 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
 612                 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
 613                 .qlen = 0,
 614                 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
 615         },
 616         .skb_bad_txq = {
 617                 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
 618                 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
 619                 .qlen = 0,
 620                 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
 621         },
 622 };
 623 EXPORT_SYMBOL(noop_qdisc);
 624
 625 static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
 626                         struct netlink_ext_ack *extack)
 627 {
 628         /* register_qdisc() assigns a default of noop_enqueue if unset,
 629          * but __dev_queue_xmit() treats noqueue only as such
 630          * if this is NULL - so clear it here. */
 631         qdisc->enqueue = NULL;
 632         return 0;
 633 }
 634
 635 struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
 636         .id             =       "noqueue",
 637         .priv_size      =       0,
 638         .init           =       noqueue_init,
 639         .enqueue        =       noop_enqueue,
 640         .dequeue        =       noop_dequeue,
 641         .peek           =       noop_dequeue,
 642         .owner          =       THIS_MODULE,
 643 };
 644
 645 static const u8 prio2band[TC_PRIO_MAX + 1] = {
 646         1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
 647 };
 648
 649 /* 3-band FIFO queue: old style, but should be a bit faster than
 650    generic prio+fifo combination.
 651  */
 652
 653 #define PFIFO_FAST_BANDS 3
 654
 655 /*
 656  * Private data for a pfifo_fast scheduler containing:
 657  *      - rings for priority bands
 658  */
 659 struct pfifo_fast_priv {
 660         struct skb_array q[PFIFO_FAST_BANDS];
 661 };
 662
 663 static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
 664                                           int band)
 665 {
 666         return &priv->q[band];
 667 }
 668
 669 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
 670                               struct sk_buff **to_free)
 671 {
 672         int band = prio2band[skb->priority & TC_PRIO_MAX];
 673         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 674         struct skb_array *q = band2list(priv, band);
 675         unsigned int pkt_len = qdisc_pkt_len(skb);
 676         int err;
 677
 678         err = skb_array_produce(q, skb);
 679
 680         if (unlikely(err)) {
 681                 if (qdisc_is_percpu_stats(qdisc))
 682                         return qdisc_drop_cpu(skb, qdisc, to_free);
 683                 else
 684                         return qdisc_drop(skb, qdisc, to_free);
 685         }
 686
 687         qdisc_update_stats_at_enqueue(qdisc, pkt_len);
 688         return NET_XMIT_SUCCESS;
 689 }
 690
 691 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
 692 {
 693         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 694         struct sk_buff *skb = NULL;
 695         bool need_retry = true;
 696         int band;
 697
 698 retry:
 699         for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
 700                 struct skb_array *q = band2list(priv, band);
 701
 702                 if (__skb_array_empty(q))
 703                         continue;
 704
 705                 skb = __skb_array_consume(q);
 706         }
 707         if (likely(skb)) {
 708                 qdisc_update_stats_at_dequeue(qdisc, skb);
 709         } else if (need_retry &&
 710                    READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY) {
 711                 /* Delay clearing the STATE_MISSED here to reduce
 712                  * the overhead of the second spin_trylock() in
 713                  * qdisc_run_begin() and __netif_schedule() calling
 714                  * in qdisc_run_end().
 715                  */
 716                 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
 717                 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
 718
 719                 /* Make sure dequeuing happens after clearing
 720                  * STATE_MISSED.
 721                  */
 722                 smp_mb__after_atomic();
 723
 724                 need_retry = false;
 725
 726                 goto retry;
 727         }
 728
 729         return skb;
 730 }
 731
 732 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
 733 {
 734         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 735         struct sk_buff *skb = NULL;
 736         int band;
 737
 738         for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
 739                 struct skb_array *q = band2list(priv, band);
 740
 741                 skb = __skb_array_peek(q);
 742         }
 743
 744         return skb;
 745 }
 746
 747 static void pfifo_fast_reset(struct Qdisc *qdisc)
 748 {
 749         int i, band;
 750         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 751
 752         for (band = 0; band < PFIFO_FAST_BANDS; band++) {
 753                 struct skb_array *q = band2list(priv, band);
 754                 struct sk_buff *skb;
 755
 756                 /* NULL ring is possible if destroy path is due to a failed
 757                  * skb_array_init() in pfifo_fast_init() case.
 758                  */
 759                 if (!q->ring.queue)
 760                         continue;
 761
 762                 while ((skb = __skb_array_consume(q)) != NULL)
 763                         kfree_skb(skb);
 764         }
 765
 766         if (qdisc_is_percpu_stats(qdisc)) {
 767                 for_each_possible_cpu(i) {
 768                         struct gnet_stats_queue *q;
 769
 770                         q = per_cpu_ptr(qdisc->cpu_qstats, i);
 771                         q->backlog = 0;
 772                         q->qlen = 0;
 773                 }
 774         }
 775 }
 776
 777 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
 778 {
 779         struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
 780
 781         memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
 782         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 783                 goto nla_put_failure;
 784         return skb->len;
 785
 786 nla_put_failure:
 787         return -1;
 788 }
 789
 790 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
 791                            struct netlink_ext_ack *extack)
 792 {
 793         unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
 794         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 795         int prio;
 796
 797         /* guard against zero length rings */
 798         if (!qlen)
 799                 return -EINVAL;
 800
 801         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 802                 struct skb_array *q = band2list(priv, prio);
 803                 int err;
 804
 805                 err = skb_array_init(q, qlen, GFP_KERNEL);
 806                 if (err)
 807                         return -ENOMEM;
 808         }
 809
 810         /* Can by-pass the queue discipline */
 811         qdisc->flags |= TCQ_F_CAN_BYPASS;
 812         return 0;
 813 }
 814
 815 static void pfifo_fast_destroy(struct Qdisc *sch)
 816 {
 817         struct pfifo_fast_priv *priv = qdisc_priv(sch);
 818         int prio;
 819
 820         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 821                 struct skb_array *q = band2list(priv, prio);
 822
 823                 /* NULL ring is possible if destroy path is due to a failed
 824                  * skb_array_init() in pfifo_fast_init() case.
 825                  */
 826                 if (!q->ring.queue)
 827                         continue;
 828                 /* Destroy ring but no need to kfree_skb because a call to
 829                  * pfifo_fast_reset() has already done that work.
 830                  */
 831                 ptr_ring_cleanup(&q->ring, NULL);
 832         }
 833 }
 834
 835 static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
 836                                           unsigned int new_len)
 837 {
 838         struct pfifo_fast_priv *priv = qdisc_priv(sch);
 839         struct skb_array *bands[PFIFO_FAST_BANDS];
 840         int prio;
 841
 842         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 843                 struct skb_array *q = band2list(priv, prio);
 844
 845                 bands[prio] = q;
 846         }
 847
 848         return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
 849                                          GFP_KERNEL);
 850 }
 851
 852 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
 853         .id             =       "pfifo_fast",
 854         .priv_size      =       sizeof(struct pfifo_fast_priv),
 855         .enqueue        =       pfifo_fast_enqueue,
 856         .dequeue        =       pfifo_fast_dequeue,
 857         .peek           =       pfifo_fast_peek,
 858         .init           =       pfifo_fast_init,
 859         .destroy        =       pfifo_fast_destroy,
 860         .reset          =       pfifo_fast_reset,
 861         .dump           =       pfifo_fast_dump,
 862         .change_tx_queue_len =  pfifo_fast_change_tx_queue_len,
 863         .owner          =       THIS_MODULE,
 864         .static_flags   =       TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
 865 };
 866 EXPORT_SYMBOL(pfifo_fast_ops);
 867
 868 static struct lock_class_key qdisc_tx_busylock;
 869
 870 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 871                           const struct Qdisc_ops *ops,
 872                           struct netlink_ext_ack *extack)
 873 {
 874         struct Qdisc *sch;
 875         unsigned int size = sizeof(*sch) + ops->priv_size;
 876         int err = -ENOBUFS;
 877         struct net_device *dev;
 878
 879         if (!dev_queue) {
 880                 NL_SET_ERR_MSG(extack, "No device queue given");
 881                 err = -EINVAL;
 882                 goto errout;
 883         }
 884
 885         dev = dev_queue->dev;
 886         sch = kzalloc_node(size, GFP_KERNEL, netdev_queue_numa_node_read(dev_queue));
 887
 888         if (!sch)
 889                 goto errout;
 890         __skb_queue_head_init(&sch->gso_skb);
 891         __skb_queue_head_init(&sch->skb_bad_txq);
 892         qdisc_skb_head_init(&sch->q);
 893         gnet_stats_basic_sync_init(&sch->bstats);
 894         spin_lock_init(&sch->q.lock);
 895
 896         if (ops->static_flags & TCQ_F_CPUSTATS) {
 897                 sch->cpu_bstats =
 898                         netdev_alloc_pcpu_stats(struct gnet_stats_basic_sync);
 899                 if (!sch->cpu_bstats)
 900                         goto errout1;
 901
 902                 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
 903                 if (!sch->cpu_qstats) {
 904                         free_percpu(sch->cpu_bstats);
 905                         goto errout1;
 906                 }
 907         }
 908
 909         spin_lock_init(&sch->busylock);
 910         lockdep_set_class(&sch->busylock,
 911                           dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
 912
 913         /* seqlock has the same scope of busylock, for NOLOCK qdisc */
 914         spin_lock_init(&sch->seqlock);
 915         lockdep_set_class(&sch->seqlock,
 916                           dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
 917
 918         sch->ops = ops;
 919         sch->flags = ops->static_flags;
 920         sch->enqueue = ops->enqueue;
 921         sch->dequeue = ops->dequeue;
 922         sch->dev_queue = dev_queue;
 923         dev_hold(dev);
 924         refcount_set(&sch->refcnt, 1);
 925
 926         return sch;
 927 errout1:
 928         kfree(sch);
 929 errout:
 930         return ERR_PTR(err);
 931 }
 932
 933 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 934                                 const struct Qdisc_ops *ops,
 935                                 unsigned int parentid,
 936                                 struct netlink_ext_ack *extack)
 937 {
 938         struct Qdisc *sch;
 939
 940         if (!try_module_get(ops->owner)) {
 941                 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
 942                 return NULL;
 943         }
 944
 945         sch = qdisc_alloc(dev_queue, ops, extack);
 946         if (IS_ERR(sch)) {
 947                 module_put(ops->owner);
 948                 return NULL;
 949         }
 950         sch->parent = parentid;
 951
 952         if (!ops->init || ops->init(sch, NULL, extack) == 0) {
 953                 trace_qdisc_create(ops, dev_queue->dev, parentid);
 954                 return sch;
 955         }
 956
 957         qdisc_put(sch);
 958         return NULL;
 959 }
 960 EXPORT_SYMBOL(qdisc_create_dflt);
 961
 962 /* Under qdisc_lock(qdisc) and BH! */
 963
 964 void qdisc_reset(struct Qdisc *qdisc)
 965 {
 966         const struct Qdisc_ops *ops = qdisc->ops;
 967         struct sk_buff *skb, *tmp;
 968
 969         trace_qdisc_reset(qdisc);
 970
 971         if (ops->reset)
 972                 ops->reset(qdisc);
 973
 974         skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
 975                 __skb_unlink(skb, &qdisc->gso_skb);
 976                 kfree_skb_list(skb);
 977         }
 978
 979         skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
 980                 __skb_unlink(skb, &qdisc->skb_bad_txq);
 981                 kfree_skb_list(skb);
 982         }
 983
 984         qdisc->q.qlen = 0;
 985         qdisc->qstats.backlog = 0;
 986 }
 987 EXPORT_SYMBOL(qdisc_reset);
 988
 989 void qdisc_free(struct Qdisc *qdisc)
 990 {
 991         if (qdisc_is_percpu_stats(qdisc)) {
 992                 free_percpu(qdisc->cpu_bstats);
 993                 free_percpu(qdisc->cpu_qstats);
 994         }
 995
 996         kfree(qdisc);
 997 }
 998
 999 static void qdisc_free_cb(struct rcu_head *head)
1000 {
1001         struct Qdisc *q = container_of(head, struct Qdisc, rcu);
1002
1003         qdisc_free(q);
1004 }
1005
1006 static void qdisc_destroy(struct Qdisc *qdisc)
1007 {
1008         const struct Qdisc_ops  *ops = qdisc->ops;
1009
1010 #ifdef CONFIG_NET_SCHED
1011         qdisc_hash_del(qdisc);
1012
1013         qdisc_put_stab(rtnl_dereference(qdisc->stab));
1014 #endif
1015         gen_kill_estimator(&qdisc->rate_est);
1016
1017         qdisc_reset(qdisc);
1018
1019         if (ops->destroy)
1020                 ops->destroy(qdisc);
1021
1022         module_put(ops->owner);
1023         dev_put(qdisc_dev(qdisc));
1024
1025         trace_qdisc_destroy(qdisc);
1026
1027         call_rcu(&qdisc->rcu, qdisc_free_cb);
1028 }
1029
1030 void qdisc_put(struct Qdisc *qdisc)
1031 {
1032         if (!qdisc)
1033                 return;
1034
1035         if (qdisc->flags & TCQ_F_BUILTIN ||
1036             !refcount_dec_and_test(&qdisc->refcnt))
1037                 return;
1038
1039         qdisc_destroy(qdisc);
1040 }
1041 EXPORT_SYMBOL(qdisc_put);
1042
1043 /* Version of qdisc_put() that is called with rtnl mutex unlocked.
1044  * Intended to be used as optimization, this function only takes rtnl lock if
1045  * qdisc reference counter reached zero.
1046  */
1047
1048 void qdisc_put_unlocked(struct Qdisc *qdisc)
1049 {
1050         if (qdisc->flags & TCQ_F_BUILTIN ||
1051             !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1052                 return;
1053
1054         qdisc_destroy(qdisc);
1055         rtnl_unlock();
1056 }
1057 EXPORT_SYMBOL(qdisc_put_unlocked);
1058
1059 /* Attach toplevel qdisc to device queue. */
1060 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1061                               struct Qdisc *qdisc)
1062 {
1063         struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1064         spinlock_t *root_lock;
1065
1066         root_lock = qdisc_lock(oqdisc);
1067         spin_lock_bh(root_lock);
1068
1069         /* ... and graft new one */
1070         if (qdisc == NULL)
1071                 qdisc = &noop_qdisc;
1072         dev_queue->qdisc_sleeping = qdisc;
1073         rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1074
1075         spin_unlock_bh(root_lock);
1076
1077         return oqdisc;
1078 }
1079 EXPORT_SYMBOL(dev_graft_qdisc);
1080
1081 static void attach_one_default_qdisc(struct net_device *dev,
1082                                      struct netdev_queue *dev_queue,
1083                                      void *_unused)
1084 {
1085         struct Qdisc *qdisc;
1086         const struct Qdisc_ops *ops = default_qdisc_ops;
1087
1088         if (dev->priv_flags & IFF_NO_QUEUE)
1089                 ops = &noqueue_qdisc_ops;
1090         else if(dev->type == ARPHRD_CAN)
1091                 ops = &pfifo_fast_ops;
1092
1093         qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1094         if (!qdisc)
1095                 return;
1096
1097         if (!netif_is_multiqueue(dev))
1098                 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1099         dev_queue->qdisc_sleeping = qdisc;
1100 }
1101
1102 static void attach_default_qdiscs(struct net_device *dev)
1103 {
1104         struct netdev_queue *txq;
1105         struct Qdisc *qdisc;
1106
1107         txq = netdev_get_tx_queue(dev, 0);
1108
1109         if (!netif_is_multiqueue(dev) ||
1110             dev->priv_flags & IFF_NO_QUEUE) {
1111                 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1112                 dev->qdisc = txq->qdisc_sleeping;
1113                 qdisc_refcount_inc(dev->qdisc);
1114         } else {
1115                 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1116                 if (qdisc) {
1117                         dev->qdisc = qdisc;
1118                         qdisc->ops->attach(qdisc);
1119                 }
1120         }
1121
1122         /* Detect default qdisc setup/init failed and fallback to "noqueue" */
1123         if (dev->qdisc == &noop_qdisc) {
1124                 netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
1125                             default_qdisc_ops->id, noqueue_qdisc_ops.id);
1126                 dev->priv_flags |= IFF_NO_QUEUE;
1127                 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1128                 dev->qdisc = txq->qdisc_sleeping;
1129                 qdisc_refcount_inc(dev->qdisc);
1130                 dev->priv_flags ^= IFF_NO_QUEUE;
1131         }
1132
1133 #ifdef CONFIG_NET_SCHED
1134         if (dev->qdisc != &noop_qdisc)
1135                 qdisc_hash_add(dev->qdisc, false);
1136 #endif
1137 }
1138
1139 static void transition_one_qdisc(struct net_device *dev,
1140                                  struct netdev_queue *dev_queue,
1141                                  void *_need_watchdog)
1142 {
1143         struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1144         int *need_watchdog_p = _need_watchdog;
1145
1146         if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1147                 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1148
1149         rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1150         if (need_watchdog_p) {
1151                 dev_queue->trans_start = 0;
1152                 *need_watchdog_p = 1;
1153         }
1154 }
1155
1156 void dev_activate(struct net_device *dev)
1157 {
1158         int need_watchdog;
1159
1160         /* No queueing discipline is attached to device;
1161          * create default one for devices, which need queueing
1162          * and noqueue_qdisc for virtual interfaces
1163          */
1164
1165         if (dev->qdisc == &noop_qdisc)
1166                 attach_default_qdiscs(dev);
1167
1168         if (!netif_carrier_ok(dev))
1169                 /* Delay activation until next carrier-on event */
1170                 return;
1171
1172         need_watchdog = 0;
1173         netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1174         if (dev_ingress_queue(dev))
1175                 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1176
1177         if (need_watchdog) {
1178                 netif_trans_update(dev);
1179                 dev_watchdog_up(dev);
1180         }
1181 }
1182 EXPORT_SYMBOL(dev_activate);
1183
1184 static void qdisc_deactivate(struct Qdisc *qdisc)
1185 {
1186         if (qdisc->flags & TCQ_F_BUILTIN)
1187                 return;
1188
1189         set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1190 }
1191
1192 static void dev_deactivate_queue(struct net_device *dev,
1193                                  struct netdev_queue *dev_queue,
1194                                  void *_qdisc_default)
1195 {
1196         struct Qdisc *qdisc_default = _qdisc_default;
1197         struct Qdisc *qdisc;
1198
1199         qdisc = rtnl_dereference(dev_queue->qdisc);
1200         if (qdisc) {
1201                 qdisc_deactivate(qdisc);
1202                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1203         }
1204 }
1205
1206 static void dev_reset_queue(struct net_device *dev,
1207                             struct netdev_queue *dev_queue,
1208                             void *_unused)
1209 {
1210         struct Qdisc *qdisc;
1211         bool nolock;
1212
1213         qdisc = dev_queue->qdisc_sleeping;
1214         if (!qdisc)
1215                 return;
1216
1217         nolock = qdisc->flags & TCQ_F_NOLOCK;
1218
1219         if (nolock)
1220                 spin_lock_bh(&qdisc->seqlock);
1221         spin_lock_bh(qdisc_lock(qdisc));
1222
1223         qdisc_reset(qdisc);
1224
1225         spin_unlock_bh(qdisc_lock(qdisc));
1226         if (nolock) {
1227                 clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
1228                 clear_bit(__QDISC_STATE_DRAINING, &qdisc->state);
1229                 spin_unlock_bh(&qdisc->seqlock);
1230         }
1231 }
1232
1233 static bool some_qdisc_is_busy(struct net_device *dev)
1234 {
1235         unsigned int i;
1236
1237         for (i = 0; i < dev->num_tx_queues; i++) {
1238                 struct netdev_queue *dev_queue;
1239                 spinlock_t *root_lock;
1240                 struct Qdisc *q;
1241                 int val;
1242
1243                 dev_queue = netdev_get_tx_queue(dev, i);
1244                 q = dev_queue->qdisc_sleeping;
1245
1246                 root_lock = qdisc_lock(q);
1247                 spin_lock_bh(root_lock);
1248
1249                 val = (qdisc_is_running(q) ||
1250                        test_bit(__QDISC_STATE_SCHED, &q->state));
1251
1252                 spin_unlock_bh(root_lock);
1253
1254                 if (val)
1255                         return true;
1256         }
1257         return false;
1258 }
1259
1260 /**
1261  *      dev_deactivate_many - deactivate transmissions on several devices
1262  *      @head: list of devices to deactivate
1263  *
1264  *      This function returns only when all outstanding transmissions
1265  *      have completed, unless all devices are in dismantle phase.
1266  */
1267 void dev_deactivate_many(struct list_head *head)
1268 {
1269         struct net_device *dev;
1270
1271         list_for_each_entry(dev, head, close_list) {
1272                 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1273                                          &noop_qdisc);
1274                 if (dev_ingress_queue(dev))
1275                         dev_deactivate_queue(dev, dev_ingress_queue(dev),
1276                                              &noop_qdisc);
1277
1278                 dev_watchdog_down(dev);
1279         }
1280
1281         /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1282          * outstanding qdisc enqueuing calls.
1283          * This is avoided if all devices are in dismantle phase :
1284          * Caller will call synchronize_net() for us
1285          */
1286         synchronize_net();
1287
1288         list_for_each_entry(dev, head, close_list) {
1289                 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1290
1291                 if (dev_ingress_queue(dev))
1292                         dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1293         }
1294
1295         /* Wait for outstanding qdisc_run calls. */
1296         list_for_each_entry(dev, head, close_list) {
1297                 while (some_qdisc_is_busy(dev)) {
1298                         /* wait_event() would avoid this sleep-loop but would
1299                          * require expensive checks in the fast paths of packet
1300                          * processing which isn't worth it.
1301                          */
1302                         schedule_timeout_uninterruptible(1);
1303                 }
1304         }
1305 }
1306
1307 void dev_deactivate(struct net_device *dev)
1308 {
1309         LIST_HEAD(single);
1310
1311         list_add(&dev->close_list, &single);
1312         dev_deactivate_many(&single);
1313         list_del(&single);
1314 }
1315 EXPORT_SYMBOL(dev_deactivate);
1316
1317 static int qdisc_change_tx_queue_len(struct net_device *dev,
1318                                      struct netdev_queue *dev_queue)
1319 {
1320         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1321         const struct Qdisc_ops *ops = qdisc->ops;
1322
1323         if (ops->change_tx_queue_len)
1324                 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1325         return 0;
1326 }
1327
1328 void dev_qdisc_change_real_num_tx(struct net_device *dev,
1329                                   unsigned int new_real_tx)
1330 {
1331         struct Qdisc *qdisc = dev->qdisc;
1332
1333         if (qdisc->ops->change_real_num_tx)
1334                 qdisc->ops->change_real_num_tx(qdisc, new_real_tx);
1335 }
1336
1337 void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx)
1338 {
1339 #ifdef CONFIG_NET_SCHED
1340         struct net_device *dev = qdisc_dev(sch);
1341         struct Qdisc *qdisc;
1342         unsigned int i;
1343
1344         for (i = new_real_tx; i < dev->real_num_tx_queues; i++) {
1345                 qdisc = netdev_get_tx_queue(dev, i)->qdisc_sleeping;
1346                 /* Only update the default qdiscs we created,
1347                  * qdiscs with handles are always hashed.
1348                  */
1349                 if (qdisc != &noop_qdisc && !qdisc->handle)
1350                         qdisc_hash_del(qdisc);
1351         }
1352         for (i = dev->real_num_tx_queues; i < new_real_tx; i++) {
1353                 qdisc = netdev_get_tx_queue(dev, i)->qdisc_sleeping;
1354                 if (qdisc != &noop_qdisc && !qdisc->handle)
1355                         qdisc_hash_add(qdisc, false);
1356         }
1357 #endif
1358 }
1359 EXPORT_SYMBOL(mq_change_real_num_tx);
1360
1361 int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1362 {
1363         bool up = dev->flags & IFF_UP;
1364         unsigned int i;
1365         int ret = 0;
1366
1367         if (up)
1368                 dev_deactivate(dev);
1369
1370         for (i = 0; i < dev->num_tx_queues; i++) {
1371                 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1372
1373                 /* TODO: revert changes on a partial failure */
1374                 if (ret)
1375                         break;
1376         }
1377
1378         if (up)
1379                 dev_activate(dev);
1380         return ret;
1381 }
1382
1383 static void dev_init_scheduler_queue(struct net_device *dev,
1384                                      struct netdev_queue *dev_queue,
1385                                      void *_qdisc)
1386 {
1387         struct Qdisc *qdisc = _qdisc;
1388
1389         rcu_assign_pointer(dev_queue->qdisc, qdisc);
1390         dev_queue->qdisc_sleeping = qdisc;
1391 }
1392
1393 void dev_init_scheduler(struct net_device *dev)
1394 {
1395         dev->qdisc = &noop_qdisc;
1396         netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1397         if (dev_ingress_queue(dev))
1398                 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1399
1400         timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1401 }
1402
1403 static void shutdown_scheduler_queue(struct net_device *dev,
1404                                      struct netdev_queue *dev_queue,
1405                                      void *_qdisc_default)
1406 {
1407         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1408         struct Qdisc *qdisc_default = _qdisc_default;
1409
1410         if (qdisc) {
1411                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1412                 dev_queue->qdisc_sleeping = qdisc_default;
1413
1414                 qdisc_put(qdisc);
1415         }
1416 }
1417
1418 void dev_shutdown(struct net_device *dev)
1419 {
1420         netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1421         if (dev_ingress_queue(dev))
1422                 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1423         qdisc_put(dev->qdisc);
1424         dev->qdisc = &noop_qdisc;
1425
1426         WARN_ON(timer_pending(&dev->watchdog_timer));
1427 }
1428
1429 /**
1430  * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division
1431  * @rate:   Rate to compute reciprocal division values of
1432  * @mult:   Multiplier for reciprocal division
1433  * @shift:  Shift for reciprocal division
1434  *
1435  * The multiplier and shift for reciprocal division by rate are stored
1436  * in mult and shift.
1437  *
1438  * The deal here is to replace a divide by a reciprocal one
1439  * in fast path (a reciprocal divide is a multiply and a shift)
1440  *
1441  * Normal formula would be :
1442  *  time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1443  *
1444  * We compute mult/shift to use instead :
1445  *  time_in_ns = (len * mult) >> shift;
1446  *
1447  * We try to get the highest possible mult value for accuracy,
1448  * but have to make sure no overflows will ever happen.
1449  *
1450  * reciprocal_value() is not used here it doesn't handle 64-bit values.
1451  */
1452 static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift)
1453 {
1454         u64 factor = NSEC_PER_SEC;
1455
1456         *mult = 1;
1457         *shift = 0;
1458
1459         if (rate <= 0)
1460                 return;
1461
1462         for (;;) {
1463                 *mult = div64_u64(factor, rate);
1464                 if (*mult & (1U << 31) || factor & (1ULL << 63))
1465                         break;
1466                 factor <<= 1;
1467                 (*shift)++;
1468         }
1469 }
1470
1471 void psched_ratecfg_precompute(struct psched_ratecfg *r,
1472                                const struct tc_ratespec *conf,
1473                                u64 rate64)
1474 {
1475         memset(r, 0, sizeof(*r));
1476         r->overhead = conf->overhead;
1477         r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1478         r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1479         psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift);
1480 }
1481 EXPORT_SYMBOL(psched_ratecfg_precompute);
1482
1483 void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64)
1484 {
1485         r->rate_pkts_ps = pktrate64;
1486         psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift);
1487 }
1488 EXPORT_SYMBOL(psched_ppscfg_precompute);
1489
1490 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1491                           struct tcf_proto *tp_head)
1492 {
1493         /* Protected with chain0->filter_chain_lock.
1494          * Can't access chain directly because tp_head can be NULL.
1495          */
1496         struct mini_Qdisc *miniq_old =
1497                 rcu_dereference_protected(*miniqp->p_miniq, 1);
1498         struct mini_Qdisc *miniq;
1499
1500         if (!tp_head) {
1501                 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1502         } else {
1503                 miniq = miniq_old != &miniqp->miniq1 ?
1504                         &miniqp->miniq1 : &miniqp->miniq2;
1505
1506                 /* We need to make sure that readers won't see the miniq
1507                  * we are about to modify. So ensure that at least one RCU
1508                  * grace period has elapsed since the miniq was made
1509                  * inactive.
1510                  */
1511                 if (IS_ENABLED(CONFIG_PREEMPT_RT))
1512                         cond_synchronize_rcu(miniq->rcu_state);
1513                 else if (!poll_state_synchronize_rcu(miniq->rcu_state))
1514                         synchronize_rcu_expedited();
1515
1516                 miniq->filter_list = tp_head;
1517                 rcu_assign_pointer(*miniqp->p_miniq, miniq);
1518         }
1519
1520         if (miniq_old)
1521                 /* This is counterpart of the rcu sync above. We need to
1522                  * block potential new user of miniq_old until all readers
1523                  * are not seeing it.
1524                  */
1525                 miniq_old->rcu_state = start_poll_synchronize_rcu();
1526 }
1527 EXPORT_SYMBOL(mini_qdisc_pair_swap);
1528
1529 void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1530                                 struct tcf_block *block)
1531 {
1532         miniqp->miniq1.block = block;
1533         miniqp->miniq2.block = block;
1534 }
1535 EXPORT_SYMBOL(mini_qdisc_pair_block_init);
1536
1537 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1538                           struct mini_Qdisc __rcu **p_miniq)
1539 {
1540         miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1541         miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1542         miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1543         miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1544         miniqp->miniq1.rcu_state = get_state_synchronize_rcu();
1545         miniqp->miniq2.rcu_state = miniqp->miniq1.rcu_state;
1546         miniqp->p_miniq = p_miniq;
1547 }
1548 EXPORT_SYMBOL(mini_qdisc_pair_init);