net/sched/sch_generic.c

   1 /*
   2  * net/sched/sch_generic.c      Generic packet scheduler routines.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *              Jamal Hadi Salim, <hadi@cyberus.ca> 990601
  11  *              - Ingress support
  12  */
  13
  14 #include <linux/bitops.h>
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/string.h>
  20 #include <linux/errno.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/rtnetlink.h>
  24 #include <linux/init.h>
  25 #include <linux/rcupdate.h>
  26 #include <linux/list.h>
  27 #include <linux/slab.h>
  28 #include <linux/if_vlan.h>
  29 #include <linux/skb_array.h>
  30 #include <linux/if_macvlan.h>
  31 #include <net/sch_generic.h>
  32 #include <net/pkt_sched.h>
  33 #include <net/dst.h>
  34 #include <trace/events/qdisc.h>
  35 #include <net/xfrm.h>
  36
  37 /* Qdisc to use by default */
  38 const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops;
  39 EXPORT_SYMBOL(default_qdisc_ops);
  40
  41 /* Main transmission queue. */
  42
  43 /* Modifications to data participating in scheduling must be protected with
  44  * qdisc_lock(qdisc) spinlock.
  45  *
  46  * The idea is the following:
  47  * - enqueue, dequeue are serialized via qdisc root lock
  48  * - ingress filtering is also serialized via qdisc root lock
  49  * - updates to tree and tree walking are only done under the rtnl mutex.
  50  */
  51
  52 #define SKB_XOFF_MAGIC ((struct sk_buff *)1UL)
  53
  54 static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
  55 {
  56         const struct netdev_queue *txq = q->dev_queue;
  57         spinlock_t *lock = NULL;
  58         struct sk_buff *skb;
  59
  60         if (q->flags & TCQ_F_NOLOCK) {
  61                 lock = qdisc_lock(q);
  62                 spin_lock(lock);
  63         }
  64
  65         skb = skb_peek(&q->skb_bad_txq);
  66         if (skb) {
  67                 /* check the reason of requeuing without tx lock first */
  68                 txq = skb_get_tx_queue(txq->dev, skb);
  69                 if (!netif_xmit_frozen_or_stopped(txq)) {
  70                         skb = __skb_dequeue(&q->skb_bad_txq);
  71                         if (qdisc_is_percpu_stats(q)) {
  72                                 qdisc_qstats_cpu_backlog_dec(q, skb);
  73                                 qdisc_qstats_atomic_qlen_dec(q);
  74                         } else {
  75                                 qdisc_qstats_backlog_dec(q, skb);
  76                                 q->q.qlen--;
  77                         }
  78                 } else {
  79                         skb = SKB_XOFF_MAGIC;
  80                 }
  81         }
  82
  83         if (lock)
  84                 spin_unlock(lock);
  85
  86         return skb;
  87 }
  88
  89 static inline struct sk_buff *qdisc_dequeue_skb_bad_txq(struct Qdisc *q)
  90 {
  91         struct sk_buff *skb = skb_peek(&q->skb_bad_txq);
  92
  93         if (unlikely(skb))
  94                 skb = __skb_dequeue_bad_txq(q);
  95
  96         return skb;
  97 }
  98
  99 static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
 100                                              struct sk_buff *skb)
 101 {
 102         spinlock_t *lock = NULL;
 103
 104         if (q->flags & TCQ_F_NOLOCK) {
 105                 lock = qdisc_lock(q);
 106                 spin_lock(lock);
 107         }
 108
 109         __skb_queue_tail(&q->skb_bad_txq, skb);
 110
 111         if (qdisc_is_percpu_stats(q)) {
 112                 qdisc_qstats_cpu_backlog_inc(q, skb);
 113                 qdisc_qstats_atomic_qlen_inc(q);
 114         } else {
 115                 qdisc_qstats_backlog_inc(q, skb);
 116                 q->q.qlen++;
 117         }
 118
 119         if (lock)
 120                 spin_unlock(lock);
 121 }
 122
 123 static inline int __dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
 124 {
 125         while (skb) {
 126                 struct sk_buff *next = skb->next;
 127
 128                 __skb_queue_tail(&q->gso_skb, skb);
 129                 q->qstats.requeues++;
 130                 qdisc_qstats_backlog_inc(q, skb);
 131                 q->q.qlen++;    /* it's still part of the queue */
 132
 133                 skb = next;
 134         }
 135         __netif_schedule(q);
 136
 137         return 0;
 138 }
 139
 140 static inline int dev_requeue_skb_locked(struct sk_buff *skb, struct Qdisc *q)
 141 {
 142         spinlock_t *lock = qdisc_lock(q);
 143
 144         spin_lock(lock);
 145         while (skb) {
 146                 struct sk_buff *next = skb->next;
 147
 148                 __skb_queue_tail(&q->gso_skb, skb);
 149
 150                 qdisc_qstats_cpu_requeues_inc(q);
 151                 qdisc_qstats_cpu_backlog_inc(q, skb);
 152                 qdisc_qstats_atomic_qlen_inc(q);
 153
 154                 skb = next;
 155         }
 156         spin_unlock(lock);
 157
 158         __netif_schedule(q);
 159
 160         return 0;
 161 }
 162
 163 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
 164 {
 165         if (q->flags & TCQ_F_NOLOCK)
 166                 return dev_requeue_skb_locked(skb, q);
 167         else
 168                 return __dev_requeue_skb(skb, q);
 169 }
 170
 171 static void try_bulk_dequeue_skb(struct Qdisc *q,
 172                                  struct sk_buff *skb,
 173                                  const struct netdev_queue *txq,
 174                                  int *packets)
 175 {
 176         int bytelimit = qdisc_avail_bulklimit(txq) - skb->len;
 177
 178         while (bytelimit > 0) {
 179                 struct sk_buff *nskb = q->dequeue(q);
 180
 181                 if (!nskb)
 182                         break;
 183
 184                 bytelimit -= nskb->len; /* covers GSO len */
 185                 skb->next = nskb;
 186                 skb = nskb;
 187                 (*packets)++; /* GSO counts as one pkt */
 188         }
 189         skb->next = NULL;
 190 }
 191
 192 /* This variant of try_bulk_dequeue_skb() makes sure
 193  * all skbs in the chain are for the same txq
 194  */
 195 static void try_bulk_dequeue_skb_slow(struct Qdisc *q,
 196                                       struct sk_buff *skb,
 197                                       int *packets)
 198 {
 199         int mapping = skb_get_queue_mapping(skb);
 200         struct sk_buff *nskb;
 201         int cnt = 0;
 202
 203         do {
 204                 nskb = q->dequeue(q);
 205                 if (!nskb)
 206                         break;
 207                 if (unlikely(skb_get_queue_mapping(nskb) != mapping)) {
 208                         qdisc_enqueue_skb_bad_txq(q, nskb);
 209                         break;
 210                 }
 211                 skb->next = nskb;
 212                 skb = nskb;
 213         } while (++cnt < 8);
 214         (*packets) += cnt;
 215         skb->next = NULL;
 216 }
 217
 218 /* Note that dequeue_skb can possibly return a SKB list (via skb->next).
 219  * A requeued skb (via q->gso_skb) can also be a SKB list.
 220  */
 221 static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
 222                                    int *packets)
 223 {
 224         const struct netdev_queue *txq = q->dev_queue;
 225         struct sk_buff *skb = NULL;
 226
 227         *packets = 1;
 228         if (unlikely(!skb_queue_empty(&q->gso_skb))) {
 229                 spinlock_t *lock = NULL;
 230
 231                 if (q->flags & TCQ_F_NOLOCK) {
 232                         lock = qdisc_lock(q);
 233                         spin_lock(lock);
 234                 }
 235
 236                 skb = skb_peek(&q->gso_skb);
 237
 238                 /* skb may be null if another cpu pulls gso_skb off in between
 239                  * empty check and lock.
 240                  */
 241                 if (!skb) {
 242                         if (lock)
 243                                 spin_unlock(lock);
 244                         goto validate;
 245                 }
 246
 247                 /* skb in gso_skb were already validated */
 248                 *validate = false;
 249                 if (xfrm_offload(skb))
 250                         *validate = true;
 251                 /* check the reason of requeuing without tx lock first */
 252                 txq = skb_get_tx_queue(txq->dev, skb);
 253                 if (!netif_xmit_frozen_or_stopped(txq)) {
 254                         skb = __skb_dequeue(&q->gso_skb);
 255                         if (qdisc_is_percpu_stats(q)) {
 256                                 qdisc_qstats_cpu_backlog_dec(q, skb);
 257                                 qdisc_qstats_atomic_qlen_dec(q);
 258                         } else {
 259                                 qdisc_qstats_backlog_dec(q, skb);
 260                                 q->q.qlen--;
 261                         }
 262                 } else {
 263                         skb = NULL;
 264                 }
 265                 if (lock)
 266                         spin_unlock(lock);
 267                 goto trace;
 268         }
 269 validate:
 270         *validate = true;
 271
 272         if ((q->flags & TCQ_F_ONETXQUEUE) &&
 273             netif_xmit_frozen_or_stopped(txq))
 274                 return skb;
 275
 276         skb = qdisc_dequeue_skb_bad_txq(q);
 277         if (unlikely(skb)) {
 278                 if (skb == SKB_XOFF_MAGIC)
 279                         return NULL;
 280                 goto bulk;
 281         }
 282         skb = q->dequeue(q);
 283         if (skb) {
 284 bulk:
 285                 if (qdisc_may_bulk(q))
 286                         try_bulk_dequeue_skb(q, skb, txq, packets);
 287                 else
 288                         try_bulk_dequeue_skb_slow(q, skb, packets);
 289         }
 290 trace:
 291         trace_qdisc_dequeue(q, txq, *packets, skb);
 292         return skb;
 293 }
 294
 295 /*
 296  * Transmit possibly several skbs, and handle the return status as
 297  * required. Owning running seqcount bit guarantees that
 298  * only one CPU can execute this function.
 299  *
 300  * Returns to the caller:
 301  *                              false  - hardware queue frozen backoff
 302  *                              true   - feel free to send more pkts
 303  */
 304 bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 305                      struct net_device *dev, struct netdev_queue *txq,
 306                      spinlock_t *root_lock, bool validate)
 307 {
 308         int ret = NETDEV_TX_BUSY;
 309         bool again = false;
 310
 311         /* And release qdisc */
 312         if (root_lock)
 313                 spin_unlock(root_lock);
 314
 315         /* Note that we validate skb (GSO, checksum, ...) outside of locks */
 316         if (validate)
 317                 skb = validate_xmit_skb_list(skb, dev, &again);
 318
 319 #ifdef CONFIG_XFRM_OFFLOAD
 320         if (unlikely(again)) {
 321                 if (root_lock)
 322                         spin_lock(root_lock);
 323
 324                 dev_requeue_skb(skb, q);
 325                 return false;
 326         }
 327 #endif
 328
 329         if (likely(skb)) {
 330                 HARD_TX_LOCK(dev, txq, smp_processor_id());
 331                 if (!netif_xmit_frozen_or_stopped(txq))
 332                         skb = dev_hard_start_xmit(skb, dev, txq, &ret);
 333
 334                 HARD_TX_UNLOCK(dev, txq);
 335         } else {
 336                 if (root_lock)
 337                         spin_lock(root_lock);
 338                 return true;
 339         }
 340
 341         if (root_lock)
 342                 spin_lock(root_lock);
 343
 344         if (!dev_xmit_complete(ret)) {
 345                 /* Driver returned NETDEV_TX_BUSY - requeue skb */
 346                 if (unlikely(ret != NETDEV_TX_BUSY))
 347                         net_warn_ratelimited("BUG %s code %d qlen %d\n",
 348                                              dev->name, ret, q->q.qlen);
 349
 350                 dev_requeue_skb(skb, q);
 351                 return false;
 352         }
 353
 354         return true;
 355 }
 356
 357 /*
 358  * NOTE: Called under qdisc_lock(q) with locally disabled BH.
 359  *
 360  * running seqcount guarantees only one CPU can process
 361  * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 362  * this queue.
 363  *
 364  *  netif_tx_lock serializes accesses to device driver.
 365  *
 366  *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 367  *  if one is grabbed, another must be free.
 368  *
 369  * Note, that this procedure can be called by a watchdog timer
 370  *
 371  * Returns to the caller:
 372  *                              0  - queue is empty or throttled.
 373  *                              >0 - queue is not empty.
 374  *
 375  */
 376 static inline bool qdisc_restart(struct Qdisc *q, int *packets)
 377 {
 378         spinlock_t *root_lock = NULL;
 379         struct netdev_queue *txq;
 380         struct net_device *dev;
 381         struct sk_buff *skb;
 382         bool validate;
 383
 384         /* Dequeue packet */
 385         skb = dequeue_skb(q, &validate, packets);
 386         if (unlikely(!skb))
 387                 return false;
 388
 389         if (!(q->flags & TCQ_F_NOLOCK))
 390                 root_lock = qdisc_lock(q);
 391
 392         dev = qdisc_dev(q);
 393         txq = skb_get_tx_queue(dev, skb);
 394
 395         return sch_direct_xmit(skb, q, dev, txq, root_lock, validate);
 396 }
 397
 398 void __qdisc_run(struct Qdisc *q)
 399 {
 400         int quota = READ_ONCE(dev_tx_weight);
 401         int packets;
 402
 403         while (qdisc_restart(q, &packets)) {
 404                 /*
 405                  * Ordered by possible occurrence: Postpone processing if
 406                  * 1. we've exceeded packet quota
 407                  * 2. another process needs the CPU;
 408                  */
 409                 quota -= packets;
 410                 if (quota <= 0 || need_resched()) {
 411                         __netif_schedule(q);
 412                         break;
 413                 }
 414         }
 415 }
 416
 417 unsigned long dev_trans_start(struct net_device *dev)
 418 {
 419         unsigned long val, res;
 420         unsigned int i;
 421
 422         if (is_vlan_dev(dev))
 423                 dev = vlan_dev_real_dev(dev);
 424         else if (netif_is_macvlan(dev))
 425                 dev = macvlan_dev_real_dev(dev);
 426         res = netdev_get_tx_queue(dev, 0)->trans_start;
 427         for (i = 1; i < dev->num_tx_queues; i++) {
 428                 val = netdev_get_tx_queue(dev, i)->trans_start;
 429                 if (val && time_after(val, res))
 430                         res = val;
 431         }
 432
 433         return res;
 434 }
 435 EXPORT_SYMBOL(dev_trans_start);
 436
 437 static void dev_watchdog(struct timer_list *t)
 438 {
 439         struct net_device *dev = from_timer(dev, t, watchdog_timer);
 440
 441         netif_tx_lock(dev);
 442         if (!qdisc_tx_is_noop(dev)) {
 443                 if (netif_device_present(dev) &&
 444                     netif_running(dev) &&
 445                     netif_carrier_ok(dev)) {
 446                         int some_queue_timedout = 0;
 447                         unsigned int i;
 448                         unsigned long trans_start;
 449
 450                         for (i = 0; i < dev->num_tx_queues; i++) {
 451                                 struct netdev_queue *txq;
 452
 453                                 txq = netdev_get_tx_queue(dev, i);
 454                                 trans_start = txq->trans_start;
 455                                 if (netif_xmit_stopped(txq) &&
 456                                     time_after(jiffies, (trans_start +
 457                                                          dev->watchdog_timeo))) {
 458                                         some_queue_timedout = 1;
 459                                         txq->trans_timeout++;
 460                                         break;
 461                                 }
 462                         }
 463
 464                         if (some_queue_timedout) {
 465                                 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit queue %u timed out\n",
 466                                        dev->name, netdev_drivername(dev), i);
 467                                 dev->netdev_ops->ndo_tx_timeout(dev);
 468                         }
 469                         if (!mod_timer(&dev->watchdog_timer,
 470                                        round_jiffies(jiffies +
 471                                                      dev->watchdog_timeo)))
 472                                 dev_hold(dev);
 473                 }
 474         }
 475         netif_tx_unlock(dev);
 476
 477         dev_put(dev);
 478 }
 479
 480 void __netdev_watchdog_up(struct net_device *dev)
 481 {
 482         if (dev->netdev_ops->ndo_tx_timeout) {
 483                 if (dev->watchdog_timeo <= 0)
 484                         dev->watchdog_timeo = 5*HZ;
 485                 if (!mod_timer(&dev->watchdog_timer,
 486                                round_jiffies(jiffies + dev->watchdog_timeo)))
 487                         dev_hold(dev);
 488         }
 489 }
 490 EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
 491
 492 static void dev_watchdog_up(struct net_device *dev)
 493 {
 494         __netdev_watchdog_up(dev);
 495 }
 496
 497 static void dev_watchdog_down(struct net_device *dev)
 498 {
 499         netif_tx_lock_bh(dev);
 500         if (del_timer(&dev->watchdog_timer))
 501                 dev_put(dev);
 502         netif_tx_unlock_bh(dev);
 503 }
 504
 505 /**
 506  *      netif_carrier_on - set carrier
 507  *      @dev: network device
 508  *
 509  * Device has detected that carrier.
 510  */
 511 void netif_carrier_on(struct net_device *dev)
 512 {
 513         if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
 514                 if (dev->reg_state == NETREG_UNINITIALIZED)
 515                         return;
 516                 atomic_inc(&dev->carrier_up_count);
 517                 linkwatch_fire_event(dev);
 518                 if (netif_running(dev))
 519                         __netdev_watchdog_up(dev);
 520         }
 521 }
 522 EXPORT_SYMBOL(netif_carrier_on);
 523
 524 /**
 525  *      netif_carrier_off - clear carrier
 526  *      @dev: network device
 527  *
 528  * Device has detected loss of carrier.
 529  */
 530 void netif_carrier_off(struct net_device *dev)
 531 {
 532         if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
 533                 if (dev->reg_state == NETREG_UNINITIALIZED)
 534                         return;
 535                 atomic_inc(&dev->carrier_down_count);
 536                 linkwatch_fire_event(dev);
 537         }
 538 }
 539 EXPORT_SYMBOL(netif_carrier_off);
 540
 541 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
 542    under all circumstances. It is difficult to invent anything faster or
 543    cheaper.
 544  */
 545
 546 static int noop_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
 547                         struct sk_buff **to_free)
 548 {
 549         __qdisc_drop(skb, to_free);
 550         return NET_XMIT_CN;
 551 }
 552
 553 static struct sk_buff *noop_dequeue(struct Qdisc *qdisc)
 554 {
 555         return NULL;
 556 }
 557
 558 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
 559         .id             =       "noop",
 560         .priv_size      =       0,
 561         .enqueue        =       noop_enqueue,
 562         .dequeue        =       noop_dequeue,
 563         .peek           =       noop_dequeue,
 564         .owner          =       THIS_MODULE,
 565 };
 566
 567 static struct netdev_queue noop_netdev_queue = {
 568         .qdisc          =       &noop_qdisc,
 569         .qdisc_sleeping =       &noop_qdisc,
 570 };
 571
 572 struct Qdisc noop_qdisc = {
 573         .enqueue        =       noop_enqueue,
 574         .dequeue        =       noop_dequeue,
 575         .flags          =       TCQ_F_BUILTIN,
 576         .ops            =       &noop_qdisc_ops,
 577         .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
 578         .dev_queue      =       &noop_netdev_queue,
 579         .running        =       SEQCNT_ZERO(noop_qdisc.running),
 580         .busylock       =       __SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
 581         .gso_skb = {
 582                 .next = (struct sk_buff *)&noop_qdisc.gso_skb,
 583                 .prev = (struct sk_buff *)&noop_qdisc.gso_skb,
 584                 .qlen = 0,
 585                 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.gso_skb.lock),
 586         },
 587         .skb_bad_txq = {
 588                 .next = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
 589                 .prev = (struct sk_buff *)&noop_qdisc.skb_bad_txq,
 590                 .qlen = 0,
 591                 .lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),
 592         },
 593 };
 594 EXPORT_SYMBOL(noop_qdisc);
 595
 596 static int noqueue_init(struct Qdisc *qdisc, struct nlattr *opt,
 597                         struct netlink_ext_ack *extack)
 598 {
 599         /* register_qdisc() assigns a default of noop_enqueue if unset,
 600          * but __dev_queue_xmit() treats noqueue only as such
 601          * if this is NULL - so clear it here. */
 602         qdisc->enqueue = NULL;
 603         return 0;
 604 }
 605
 606 struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
 607         .id             =       "noqueue",
 608         .priv_size      =       0,
 609         .init           =       noqueue_init,
 610         .enqueue        =       noop_enqueue,
 611         .dequeue        =       noop_dequeue,
 612         .peek           =       noop_dequeue,
 613         .owner          =       THIS_MODULE,
 614 };
 615
 616 static const u8 prio2band[TC_PRIO_MAX + 1] = {
 617         1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
 618 };
 619
 620 /* 3-band FIFO queue: old style, but should be a bit faster than
 621    generic prio+fifo combination.
 622  */
 623
 624 #define PFIFO_FAST_BANDS 3
 625
 626 /*
 627  * Private data for a pfifo_fast scheduler containing:
 628  *      - rings for priority bands
 629  */
 630 struct pfifo_fast_priv {
 631         struct skb_array q[PFIFO_FAST_BANDS];
 632 };
 633
 634 static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
 635                                           int band)
 636 {
 637         return &priv->q[band];
 638 }
 639
 640 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
 641                               struct sk_buff **to_free)
 642 {
 643         int band = prio2band[skb->priority & TC_PRIO_MAX];
 644         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 645         struct skb_array *q = band2list(priv, band);
 646         unsigned int pkt_len = qdisc_pkt_len(skb);
 647         int err;
 648
 649         err = skb_array_produce(q, skb);
 650
 651         if (unlikely(err))
 652                 return qdisc_drop_cpu(skb, qdisc, to_free);
 653
 654         qdisc_qstats_atomic_qlen_inc(qdisc);
 655         /* Note: skb can not be used after skb_array_produce(),
 656          * so we better not use qdisc_qstats_cpu_backlog_inc()
 657          */
 658         this_cpu_add(qdisc->cpu_qstats->backlog, pkt_len);
 659         return NET_XMIT_SUCCESS;
 660 }
 661
 662 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
 663 {
 664         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 665         struct sk_buff *skb = NULL;
 666         int band;
 667
 668         for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
 669                 struct skb_array *q = band2list(priv, band);
 670
 671                 if (__skb_array_empty(q))
 672                         continue;
 673
 674                 skb = __skb_array_consume(q);
 675         }
 676         if (likely(skb)) {
 677                 qdisc_qstats_cpu_backlog_dec(qdisc, skb);
 678                 qdisc_bstats_cpu_update(qdisc, skb);
 679                 qdisc_qstats_atomic_qlen_dec(qdisc);
 680         }
 681
 682         return skb;
 683 }
 684
 685 static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
 686 {
 687         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 688         struct sk_buff *skb = NULL;
 689         int band;
 690
 691         for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
 692                 struct skb_array *q = band2list(priv, band);
 693
 694                 skb = __skb_array_peek(q);
 695         }
 696
 697         return skb;
 698 }
 699
 700 static void pfifo_fast_reset(struct Qdisc *qdisc)
 701 {
 702         int i, band;
 703         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 704
 705         for (band = 0; band < PFIFO_FAST_BANDS; band++) {
 706                 struct skb_array *q = band2list(priv, band);
 707                 struct sk_buff *skb;
 708
 709                 /* NULL ring is possible if destroy path is due to a failed
 710                  * skb_array_init() in pfifo_fast_init() case.
 711                  */
 712                 if (!q->ring.queue)
 713                         continue;
 714
 715                 while ((skb = __skb_array_consume(q)) != NULL)
 716                         kfree_skb(skb);
 717         }
 718
 719         for_each_possible_cpu(i) {
 720                 struct gnet_stats_queue *q = per_cpu_ptr(qdisc->cpu_qstats, i);
 721
 722                 q->backlog = 0;
 723         }
 724 }
 725
 726 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
 727 {
 728         struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
 729
 730         memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
 731         if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 732                 goto nla_put_failure;
 733         return skb->len;
 734
 735 nla_put_failure:
 736         return -1;
 737 }
 738
 739 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
 740                            struct netlink_ext_ack *extack)
 741 {
 742         unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
 743         struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 744         int prio;
 745
 746         /* guard against zero length rings */
 747         if (!qlen)
 748                 return -EINVAL;
 749
 750         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 751                 struct skb_array *q = band2list(priv, prio);
 752                 int err;
 753
 754                 err = skb_array_init(q, qlen, GFP_KERNEL);
 755                 if (err)
 756                         return -ENOMEM;
 757         }
 758
 759         /* Can by-pass the queue discipline */
 760         qdisc->flags |= TCQ_F_CAN_BYPASS;
 761         return 0;
 762 }
 763
 764 static void pfifo_fast_destroy(struct Qdisc *sch)
 765 {
 766         struct pfifo_fast_priv *priv = qdisc_priv(sch);
 767         int prio;
 768
 769         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 770                 struct skb_array *q = band2list(priv, prio);
 771
 772                 /* NULL ring is possible if destroy path is due to a failed
 773                  * skb_array_init() in pfifo_fast_init() case.
 774                  */
 775                 if (!q->ring.queue)
 776                         continue;
 777                 /* Destroy ring but no need to kfree_skb because a call to
 778                  * pfifo_fast_reset() has already done that work.
 779                  */
 780                 ptr_ring_cleanup(&q->ring, NULL);
 781         }
 782 }
 783
 784 static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
 785                                           unsigned int new_len)
 786 {
 787         struct pfifo_fast_priv *priv = qdisc_priv(sch);
 788         struct skb_array *bands[PFIFO_FAST_BANDS];
 789         int prio;
 790
 791         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 792                 struct skb_array *q = band2list(priv, prio);
 793
 794                 bands[prio] = q;
 795         }
 796
 797         return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
 798                                          GFP_KERNEL);
 799 }
 800
 801 struct Qdisc_ops pfifo_fast_ops __read_mostly = {
 802         .id             =       "pfifo_fast",
 803         .priv_size      =       sizeof(struct pfifo_fast_priv),
 804         .enqueue        =       pfifo_fast_enqueue,
 805         .dequeue        =       pfifo_fast_dequeue,
 806         .peek           =       pfifo_fast_peek,
 807         .init           =       pfifo_fast_init,
 808         .destroy        =       pfifo_fast_destroy,
 809         .reset          =       pfifo_fast_reset,
 810         .dump           =       pfifo_fast_dump,
 811         .change_tx_queue_len =  pfifo_fast_change_tx_queue_len,
 812         .owner          =       THIS_MODULE,
 813         .static_flags   =       TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
 814 };
 815 EXPORT_SYMBOL(pfifo_fast_ops);
 816
 817 static struct lock_class_key qdisc_tx_busylock;
 818 static struct lock_class_key qdisc_running_key;
 819
 820 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 821                           const struct Qdisc_ops *ops,
 822                           struct netlink_ext_ack *extack)
 823 {
 824         void *p;
 825         struct Qdisc *sch;
 826         unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;
 827         int err = -ENOBUFS;
 828         struct net_device *dev;
 829
 830         if (!dev_queue) {
 831                 NL_SET_ERR_MSG(extack, "No device queue given");
 832                 err = -EINVAL;
 833                 goto errout;
 834         }
 835
 836         dev = dev_queue->dev;
 837         p = kzalloc_node(size, GFP_KERNEL,
 838                          netdev_queue_numa_node_read(dev_queue));
 839
 840         if (!p)
 841                 goto errout;
 842         sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
 843         /* if we got non aligned memory, ask more and do alignment ourself */
 844         if (sch != p) {
 845                 kfree(p);
 846                 p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,
 847                                  netdev_queue_numa_node_read(dev_queue));
 848                 if (!p)
 849                         goto errout;
 850                 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
 851                 sch->padded = (char *) sch - (char *) p;
 852         }
 853         __skb_queue_head_init(&sch->gso_skb);
 854         __skb_queue_head_init(&sch->skb_bad_txq);
 855         qdisc_skb_head_init(&sch->q);
 856         spin_lock_init(&sch->q.lock);
 857
 858         if (ops->static_flags & TCQ_F_CPUSTATS) {
 859                 sch->cpu_bstats =
 860                         netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
 861                 if (!sch->cpu_bstats)
 862                         goto errout1;
 863
 864                 sch->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
 865                 if (!sch->cpu_qstats) {
 866                         free_percpu(sch->cpu_bstats);
 867                         goto errout1;
 868                 }
 869         }
 870
 871         spin_lock_init(&sch->busylock);
 872         lockdep_set_class(&sch->busylock,
 873                           dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
 874
 875         /* seqlock has the same scope of busylock, for NOLOCK qdisc */
 876         spin_lock_init(&sch->seqlock);
 877         lockdep_set_class(&sch->busylock,
 878                           dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
 879
 880         seqcount_init(&sch->running);
 881         lockdep_set_class(&sch->running,
 882                           dev->qdisc_running_key ?: &qdisc_running_key);
 883
 884         sch->ops = ops;
 885         sch->flags = ops->static_flags;
 886         sch->enqueue = ops->enqueue;
 887         sch->dequeue = ops->dequeue;
 888         sch->dev_queue = dev_queue;
 889         dev_hold(dev);
 890         refcount_set(&sch->refcnt, 1);
 891
 892         return sch;
 893 errout1:
 894         kfree(p);
 895 errout:
 896         return ERR_PTR(err);
 897 }
 898
 899 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 900                                 const struct Qdisc_ops *ops,
 901                                 unsigned int parentid,
 902                                 struct netlink_ext_ack *extack)
 903 {
 904         struct Qdisc *sch;
 905
 906         if (!try_module_get(ops->owner)) {
 907                 NL_SET_ERR_MSG(extack, "Failed to increase module reference counter");
 908                 return NULL;
 909         }
 910
 911         sch = qdisc_alloc(dev_queue, ops, extack);
 912         if (IS_ERR(sch)) {
 913                 module_put(ops->owner);
 914                 return NULL;
 915         }
 916         sch->parent = parentid;
 917
 918         if (!ops->init || ops->init(sch, NULL, extack) == 0)
 919                 return sch;
 920
 921         qdisc_put(sch);
 922         return NULL;
 923 }
 924 EXPORT_SYMBOL(qdisc_create_dflt);
 925
 926 /* Under qdisc_lock(qdisc) and BH! */
 927
 928 void qdisc_reset(struct Qdisc *qdisc)
 929 {
 930         const struct Qdisc_ops *ops = qdisc->ops;
 931         struct sk_buff *skb, *tmp;
 932
 933         if (ops->reset)
 934                 ops->reset(qdisc);
 935
 936         skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
 937                 __skb_unlink(skb, &qdisc->gso_skb);
 938                 kfree_skb_list(skb);
 939         }
 940
 941         skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
 942                 __skb_unlink(skb, &qdisc->skb_bad_txq);
 943                 kfree_skb_list(skb);
 944         }
 945
 946         qdisc->q.qlen = 0;
 947         qdisc->qstats.backlog = 0;
 948 }
 949 EXPORT_SYMBOL(qdisc_reset);
 950
 951 void qdisc_free(struct Qdisc *qdisc)
 952 {
 953         if (qdisc_is_percpu_stats(qdisc)) {
 954                 free_percpu(qdisc->cpu_bstats);
 955                 free_percpu(qdisc->cpu_qstats);
 956         }
 957
 958         kfree((char *) qdisc - qdisc->padded);
 959 }
 960
 961 static void qdisc_free_cb(struct rcu_head *head)
 962 {
 963         struct Qdisc *q = container_of(head, struct Qdisc, rcu);
 964
 965         qdisc_free(q);
 966 }
 967
 968 static void qdisc_destroy(struct Qdisc *qdisc)
 969 {
 970         const struct Qdisc_ops *ops;
 971         struct sk_buff *skb, *tmp;
 972
 973         ops = qdisc->ops;
 974
 975 #ifdef CONFIG_NET_SCHED
 976         qdisc_hash_del(qdisc);
 977
 978         qdisc_put_stab(rtnl_dereference(qdisc->stab));
 979 #endif
 980         gen_kill_estimator(&qdisc->rate_est);
 981         if (ops->reset)
 982                 ops->reset(qdisc);
 983         if (ops->destroy)
 984                 ops->destroy(qdisc);
 985
 986         module_put(ops->owner);
 987         dev_put(qdisc_dev(qdisc));
 988
 989         skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
 990                 __skb_unlink(skb, &qdisc->gso_skb);
 991                 kfree_skb_list(skb);
 992         }
 993
 994         skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
 995                 __skb_unlink(skb, &qdisc->skb_bad_txq);
 996                 kfree_skb_list(skb);
 997         }
 998
 999         call_rcu(&qdisc->rcu, qdisc_free_cb);
1000 }
1001
1002 void qdisc_put(struct Qdisc *qdisc)
1003 {
1004         if (!qdisc)
1005                 return;
1006
1007         if (qdisc->flags & TCQ_F_BUILTIN ||
1008             !refcount_dec_and_test(&qdisc->refcnt))
1009                 return;
1010
1011         qdisc_destroy(qdisc);
1012 }
1013 EXPORT_SYMBOL(qdisc_put);
1014
1015 /* Version of qdisc_put() that is called with rtnl mutex unlocked.
1016  * Intended to be used as optimization, this function only takes rtnl lock if
1017  * qdisc reference counter reached zero.
1018  */
1019
1020 void qdisc_put_unlocked(struct Qdisc *qdisc)
1021 {
1022         if (qdisc->flags & TCQ_F_BUILTIN ||
1023             !refcount_dec_and_rtnl_lock(&qdisc->refcnt))
1024                 return;
1025
1026         qdisc_destroy(qdisc);
1027         rtnl_unlock();
1028 }
1029 EXPORT_SYMBOL(qdisc_put_unlocked);
1030
1031 /* Attach toplevel qdisc to device queue. */
1032 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
1033                               struct Qdisc *qdisc)
1034 {
1035         struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
1036         spinlock_t *root_lock;
1037
1038         root_lock = qdisc_lock(oqdisc);
1039         spin_lock_bh(root_lock);
1040
1041         /* ... and graft new one */
1042         if (qdisc == NULL)
1043                 qdisc = &noop_qdisc;
1044         dev_queue->qdisc_sleeping = qdisc;
1045         rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
1046
1047         spin_unlock_bh(root_lock);
1048
1049         return oqdisc;
1050 }
1051 EXPORT_SYMBOL(dev_graft_qdisc);
1052
1053 static void attach_one_default_qdisc(struct net_device *dev,
1054                                      struct netdev_queue *dev_queue,
1055                                      void *_unused)
1056 {
1057         struct Qdisc *qdisc;
1058         const struct Qdisc_ops *ops = default_qdisc_ops;
1059
1060         if (dev->priv_flags & IFF_NO_QUEUE)
1061                 ops = &noqueue_qdisc_ops;
1062
1063         qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
1064         if (!qdisc) {
1065                 netdev_info(dev, "activation failed\n");
1066                 return;
1067         }
1068         if (!netif_is_multiqueue(dev))
1069                 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
1070         dev_queue->qdisc_sleeping = qdisc;
1071 }
1072
1073 static void attach_default_qdiscs(struct net_device *dev)
1074 {
1075         struct netdev_queue *txq;
1076         struct Qdisc *qdisc;
1077
1078         txq = netdev_get_tx_queue(dev, 0);
1079
1080         if (!netif_is_multiqueue(dev) ||
1081             dev->priv_flags & IFF_NO_QUEUE) {
1082                 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
1083                 dev->qdisc = txq->qdisc_sleeping;
1084                 qdisc_refcount_inc(dev->qdisc);
1085         } else {
1086                 qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT, NULL);
1087                 if (qdisc) {
1088                         dev->qdisc = qdisc;
1089                         qdisc->ops->attach(qdisc);
1090                 }
1091         }
1092 #ifdef CONFIG_NET_SCHED
1093         if (dev->qdisc != &noop_qdisc)
1094                 qdisc_hash_add(dev->qdisc, false);
1095 #endif
1096 }
1097
1098 static void transition_one_qdisc(struct net_device *dev,
1099                                  struct netdev_queue *dev_queue,
1100                                  void *_need_watchdog)
1101 {
1102         struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
1103         int *need_watchdog_p = _need_watchdog;
1104
1105         if (!(new_qdisc->flags & TCQ_F_BUILTIN))
1106                 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
1107
1108         rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
1109         if (need_watchdog_p) {
1110                 dev_queue->trans_start = 0;
1111                 *need_watchdog_p = 1;
1112         }
1113 }
1114
1115 void dev_activate(struct net_device *dev)
1116 {
1117         int need_watchdog;
1118
1119         /* No queueing discipline is attached to device;
1120          * create default one for devices, which need queueing
1121          * and noqueue_qdisc for virtual interfaces
1122          */
1123
1124         if (dev->qdisc == &noop_qdisc)
1125                 attach_default_qdiscs(dev);
1126
1127         if (!netif_carrier_ok(dev))
1128                 /* Delay activation until next carrier-on event */
1129                 return;
1130
1131         need_watchdog = 0;
1132         netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
1133         if (dev_ingress_queue(dev))
1134                 transition_one_qdisc(dev, dev_ingress_queue(dev), NULL);
1135
1136         if (need_watchdog) {
1137                 netif_trans_update(dev);
1138                 dev_watchdog_up(dev);
1139         }
1140 }
1141 EXPORT_SYMBOL(dev_activate);
1142
1143 static void dev_deactivate_queue(struct net_device *dev,
1144                                  struct netdev_queue *dev_queue,
1145                                  void *_qdisc_default)
1146 {
1147         struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc);
1148         struct Qdisc *qdisc_default = _qdisc_default;
1149
1150         if (qdisc) {
1151                 if (!(qdisc->flags & TCQ_F_BUILTIN))
1152                         set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
1153
1154                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1155         }
1156 }
1157
1158 static void dev_reset_queue(struct net_device *dev,
1159                             struct netdev_queue *dev_queue,
1160                             void *_unused)
1161 {
1162         struct Qdisc *qdisc;
1163         bool nolock;
1164
1165         qdisc = dev_queue->qdisc_sleeping;
1166         if (!qdisc)
1167                 return;
1168
1169         nolock = qdisc->flags & TCQ_F_NOLOCK;
1170
1171         if (nolock)
1172                 spin_lock_bh(&qdisc->seqlock);
1173         spin_lock_bh(qdisc_lock(qdisc));
1174
1175         qdisc_reset(qdisc);
1176
1177         spin_unlock_bh(qdisc_lock(qdisc));
1178         if (nolock)
1179                 spin_unlock_bh(&qdisc->seqlock);
1180 }
1181
1182 static bool some_qdisc_is_busy(struct net_device *dev)
1183 {
1184         unsigned int i;
1185
1186         for (i = 0; i < dev->num_tx_queues; i++) {
1187                 struct netdev_queue *dev_queue;
1188                 spinlock_t *root_lock;
1189                 struct Qdisc *q;
1190                 int val;
1191
1192                 dev_queue = netdev_get_tx_queue(dev, i);
1193                 q = dev_queue->qdisc_sleeping;
1194
1195                 root_lock = qdisc_lock(q);
1196                 spin_lock_bh(root_lock);
1197
1198                 val = (qdisc_is_running(q) ||
1199                        test_bit(__QDISC_STATE_SCHED, &q->state));
1200
1201                 spin_unlock_bh(root_lock);
1202
1203                 if (val)
1204                         return true;
1205         }
1206         return false;
1207 }
1208
1209 static void dev_qdisc_reset(struct net_device *dev,
1210                             struct netdev_queue *dev_queue,
1211                             void *none)
1212 {
1213         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1214
1215         if (qdisc)
1216                 qdisc_reset(qdisc);
1217 }
1218
1219 /**
1220  *      dev_deactivate_many - deactivate transmissions on several devices
1221  *      @head: list of devices to deactivate
1222  *
1223  *      This function returns only when all outstanding transmissions
1224  *      have completed, unless all devices are in dismantle phase.
1225  */
1226 void dev_deactivate_many(struct list_head *head)
1227 {
1228         struct net_device *dev;
1229
1230         list_for_each_entry(dev, head, close_list) {
1231                 netdev_for_each_tx_queue(dev, dev_deactivate_queue,
1232                                          &noop_qdisc);
1233                 if (dev_ingress_queue(dev))
1234                         dev_deactivate_queue(dev, dev_ingress_queue(dev),
1235                                              &noop_qdisc);
1236
1237                 dev_watchdog_down(dev);
1238         }
1239
1240         /* Wait for outstanding qdisc-less dev_queue_xmit calls or
1241          * outstanding qdisc enqueuing calls.
1242          * This is avoided if all devices are in dismantle phase :
1243          * Caller will call synchronize_net() for us
1244          */
1245         synchronize_net();
1246
1247         list_for_each_entry(dev, head, close_list) {
1248                 netdev_for_each_tx_queue(dev, dev_reset_queue, NULL);
1249
1250                 if (dev_ingress_queue(dev))
1251                         dev_reset_queue(dev, dev_ingress_queue(dev), NULL);
1252         }
1253
1254         /* Wait for outstanding qdisc_run calls. */
1255         list_for_each_entry(dev, head, close_list) {
1256                 while (some_qdisc_is_busy(dev))
1257                         yield();
1258                 /* The new qdisc is assigned at this point so we can safely
1259                  * unwind stale skb lists and qdisc statistics
1260                  */
1261                 netdev_for_each_tx_queue(dev, dev_qdisc_reset, NULL);
1262                 if (dev_ingress_queue(dev))
1263                         dev_qdisc_reset(dev, dev_ingress_queue(dev), NULL);
1264         }
1265 }
1266
1267 void dev_deactivate(struct net_device *dev)
1268 {
1269         LIST_HEAD(single);
1270
1271         list_add(&dev->close_list, &single);
1272         dev_deactivate_many(&single);
1273         list_del(&single);
1274 }
1275 EXPORT_SYMBOL(dev_deactivate);
1276
1277 static int qdisc_change_tx_queue_len(struct net_device *dev,
1278                                      struct netdev_queue *dev_queue)
1279 {
1280         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1281         const struct Qdisc_ops *ops = qdisc->ops;
1282
1283         if (ops->change_tx_queue_len)
1284                 return ops->change_tx_queue_len(qdisc, dev->tx_queue_len);
1285         return 0;
1286 }
1287
1288 void dev_qdisc_change_real_num_tx(struct net_device *dev,
1289                                   unsigned int new_real_tx)
1290 {
1291         struct Qdisc *qdisc = dev->qdisc;
1292
1293         if (qdisc->ops->change_real_num_tx)
1294                 qdisc->ops->change_real_num_tx(qdisc, new_real_tx);
1295 }
1296
1297 int dev_qdisc_change_tx_queue_len(struct net_device *dev)
1298 {
1299         bool up = dev->flags & IFF_UP;
1300         unsigned int i;
1301         int ret = 0;
1302
1303         if (up)
1304                 dev_deactivate(dev);
1305
1306         for (i = 0; i < dev->num_tx_queues; i++) {
1307                 ret = qdisc_change_tx_queue_len(dev, &dev->_tx[i]);
1308
1309                 /* TODO: revert changes on a partial failure */
1310                 if (ret)
1311                         break;
1312         }
1313
1314         if (up)
1315                 dev_activate(dev);
1316         return ret;
1317 }
1318
1319 static void dev_init_scheduler_queue(struct net_device *dev,
1320                                      struct netdev_queue *dev_queue,
1321                                      void *_qdisc)
1322 {
1323         struct Qdisc *qdisc = _qdisc;
1324
1325         rcu_assign_pointer(dev_queue->qdisc, qdisc);
1326         dev_queue->qdisc_sleeping = qdisc;
1327 }
1328
1329 void dev_init_scheduler(struct net_device *dev)
1330 {
1331         dev->qdisc = &noop_qdisc;
1332         netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
1333         if (dev_ingress_queue(dev))
1334                 dev_init_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1335
1336         timer_setup(&dev->watchdog_timer, dev_watchdog, 0);
1337 }
1338
1339 static void shutdown_scheduler_queue(struct net_device *dev,
1340                                      struct netdev_queue *dev_queue,
1341                                      void *_qdisc_default)
1342 {
1343         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
1344         struct Qdisc *qdisc_default = _qdisc_default;
1345
1346         if (qdisc) {
1347                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
1348                 dev_queue->qdisc_sleeping = qdisc_default;
1349
1350                 qdisc_put(qdisc);
1351         }
1352 }
1353
1354 void dev_shutdown(struct net_device *dev)
1355 {
1356         netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
1357         if (dev_ingress_queue(dev))
1358                 shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
1359         qdisc_put(dev->qdisc);
1360         dev->qdisc = &noop_qdisc;
1361
1362         WARN_ON(timer_pending(&dev->watchdog_timer));
1363 }
1364
1365 void psched_ratecfg_precompute(struct psched_ratecfg *r,
1366                                const struct tc_ratespec *conf,
1367                                u64 rate64)
1368 {
1369         memset(r, 0, sizeof(*r));
1370         r->overhead = conf->overhead;
1371         r->mpu = conf->mpu;
1372         r->rate_bytes_ps = max_t(u64, conf->rate, rate64);
1373         r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK);
1374         r->mult = 1;
1375         /*
1376          * The deal here is to replace a divide by a reciprocal one
1377          * in fast path (a reciprocal divide is a multiply and a shift)
1378          *
1379          * Normal formula would be :
1380          *  time_in_ns = (NSEC_PER_SEC * len) / rate_bps
1381          *
1382          * We compute mult/shift to use instead :
1383          *  time_in_ns = (len * mult) >> shift;
1384          *
1385          * We try to get the highest possible mult value for accuracy,
1386          * but have to make sure no overflows will ever happen.
1387          */
1388         if (r->rate_bytes_ps > 0) {
1389                 u64 factor = NSEC_PER_SEC;
1390
1391                 for (;;) {
1392                         r->mult = div64_u64(factor, r->rate_bytes_ps);
1393                         if (r->mult & (1U << 31) || factor & (1ULL << 63))
1394                                 break;
1395                         factor <<= 1;
1396                         r->shift++;
1397                 }
1398         }
1399 }
1400 EXPORT_SYMBOL(psched_ratecfg_precompute);
1401
1402 static void mini_qdisc_rcu_func(struct rcu_head *head)
1403 {
1404 }
1405
1406 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1407                           struct tcf_proto *tp_head)
1408 {
1409         struct mini_Qdisc *miniq_old = rtnl_dereference(*miniqp->p_miniq);
1410         struct mini_Qdisc *miniq;
1411
1412         if (!tp_head) {
1413                 RCU_INIT_POINTER(*miniqp->p_miniq, NULL);
1414                 /* Wait for flying RCU callback before it is freed. */
1415                 rcu_barrier_bh();
1416                 return;
1417         }
1418
1419         miniq = !miniq_old || miniq_old == &miniqp->miniq2 ?
1420                 &miniqp->miniq1 : &miniqp->miniq2;
1421
1422         /* We need to make sure that readers won't see the miniq
1423          * we are about to modify. So wait until previous call_rcu_bh callback
1424          * is done.
1425          */
1426         rcu_barrier_bh();
1427         miniq->filter_list = tp_head;
1428         rcu_assign_pointer(*miniqp->p_miniq, miniq);
1429
1430         if (miniq_old)
1431                 /* This is counterpart of the rcu barriers above. We need to
1432                  * block potential new user of miniq_old until all readers
1433                  * are not seeing it.
1434                  */
1435                 call_rcu_bh(&miniq_old->rcu, mini_qdisc_rcu_func);
1436 }
1437 EXPORT_SYMBOL(mini_qdisc_pair_swap);
1438
1439 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1440                           struct mini_Qdisc __rcu **p_miniq)
1441 {
1442         miniqp->miniq1.cpu_bstats = qdisc->cpu_bstats;
1443         miniqp->miniq1.cpu_qstats = qdisc->cpu_qstats;
1444         miniqp->miniq2.cpu_bstats = qdisc->cpu_bstats;
1445         miniqp->miniq2.cpu_qstats = qdisc->cpu_qstats;
1446         miniqp->p_miniq = p_miniq;
1447 }
1448 EXPORT_SYMBOL(mini_qdisc_pair_init);