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   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 <net/pkt_sched.h>
  28
  29 /* Main transmission queue. */
  30
  31 /* Modifications to data participating in scheduling must be protected with
  32  * qdisc_lock(qdisc) spinlock.
  33  *
  34  * The idea is the following:
  35  * - enqueue, dequeue are serialized via qdisc root lock
  36  * - ingress filtering is also serialized via qdisc root lock
  37  * - updates to tree and tree walking are only done under the rtnl mutex.
  38  */
  39
  40 static inline int qdisc_qlen(struct Qdisc *q)
  41 {
  42         return q->q.qlen;
  43 }
  44
  45 static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
  46 {
  47         if (unlikely(skb->next))
  48                 __skb_queue_head(&q->requeue, skb);
  49         else
  50                 q->ops->requeue(skb, q);
  51
  52         __netif_schedule(q);
  53         return 0;
  54 }
  55
  56 static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
  57 {
  58         struct sk_buff *skb;
  59
  60         skb = __skb_dequeue(&q->requeue);
  61         if (!skb)
  62                 skb = q->dequeue(q);
  63
  64         return skb;
  65 }
  66
  67 static inline int handle_dev_cpu_collision(struct sk_buff *skb,
  68                                            struct netdev_queue *dev_queue,
  69                                            struct Qdisc *q)
  70 {
  71         int ret;
  72
  73         if (unlikely(dev_queue->xmit_lock_owner == smp_processor_id())) {
  74                 /*
  75                  * Same CPU holding the lock. It may be a transient
  76                  * configuration error, when hard_start_xmit() recurses. We
  77                  * detect it by checking xmit owner and drop the packet when
  78                  * deadloop is detected. Return OK to try the next skb.
  79                  */
  80                 kfree_skb(skb);
  81                 if (net_ratelimit())
  82                         printk(KERN_WARNING "Dead loop on netdevice %s, "
  83                                "fix it urgently!\n", dev_queue->dev->name);
  84                 ret = qdisc_qlen(q);
  85         } else {
  86                 /*
  87                  * Another cpu is holding lock, requeue & delay xmits for
  88                  * some time.
  89                  */
  90                 __get_cpu_var(netdev_rx_stat).cpu_collision++;
  91                 ret = dev_requeue_skb(skb, q);
  92         }
  93
  94         return ret;
  95 }
  96
  97 /*
  98  * NOTE: Called under qdisc_lock(q) with locally disabled BH.
  99  *
 100  * __QDISC_STATE_RUNNING guarantees only one CPU can process
 101  * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
 102  * this queue.
 103  *
 104  *  netif_tx_lock serializes accesses to device driver.
 105  *
 106  *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
 107  *  if one is grabbed, another must be free.
 108  *
 109  * Note, that this procedure can be called by a watchdog timer
 110  *
 111  * Returns to the caller:
 112  *                              0  - queue is empty or throttled.
 113  *                              >0 - queue is not empty.
 114  *
 115  */
 116 static inline int qdisc_restart(struct Qdisc *q)
 117 {
 118         struct netdev_queue *txq;
 119         int ret = NETDEV_TX_BUSY;
 120         struct net_device *dev;
 121         spinlock_t *root_lock;
 122         struct sk_buff *skb;
 123
 124         /* Dequeue packet */
 125         if (unlikely((skb = dequeue_skb(q)) == NULL))
 126                 return 0;
 127
 128         root_lock = qdisc_lock(q);
 129
 130         /* And release qdisc */
 131         spin_unlock(root_lock);
 132
 133         dev = qdisc_dev(q);
 134         txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 135
 136         HARD_TX_LOCK(dev, txq, smp_processor_id());
 137         if (!netif_tx_queue_stopped(txq) &&
 138             !netif_tx_queue_frozen(txq))
 139                 ret = dev_hard_start_xmit(skb, dev, txq);
 140         HARD_TX_UNLOCK(dev, txq);
 141
 142         spin_lock(root_lock);
 143
 144         switch (ret) {
 145         case NETDEV_TX_OK:
 146                 /* Driver sent out skb successfully */
 147                 ret = qdisc_qlen(q);
 148                 break;
 149
 150         case NETDEV_TX_LOCKED:
 151                 /* Driver try lock failed */
 152                 ret = handle_dev_cpu_collision(skb, txq, q);
 153                 break;
 154
 155         default:
 156                 /* Driver returned NETDEV_TX_BUSY - requeue skb */
 157                 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
 158                         printk(KERN_WARNING "BUG %s code %d qlen %d\n",
 159                                dev->name, ret, q->q.qlen);
 160
 161                 ret = dev_requeue_skb(skb, q);
 162                 break;
 163         }
 164
 165         if (ret && (netif_tx_queue_stopped(txq) ||
 166                     netif_tx_queue_frozen(txq)))
 167                 ret = 0;
 168
 169         return ret;
 170 }
 171
 172 void __qdisc_run(struct Qdisc *q)
 173 {
 174         unsigned long start_time = jiffies;
 175
 176         while (qdisc_restart(q)) {
 177                 /*
 178                  * Postpone processing if
 179                  * 1. another process needs the CPU;
 180                  * 2. we've been doing it for too long.
 181                  */
 182                 if (need_resched() || jiffies != start_time) {
 183                         __netif_schedule(q);
 184                         break;
 185                 }
 186         }
 187
 188         clear_bit(__QDISC_STATE_RUNNING, &q->state);
 189 }
 190
 191 static void dev_watchdog(unsigned long arg)
 192 {
 193         struct net_device *dev = (struct net_device *)arg;
 194
 195         netif_tx_lock(dev);
 196         if (!qdisc_tx_is_noop(dev)) {
 197                 if (netif_device_present(dev) &&
 198                     netif_running(dev) &&
 199                     netif_carrier_ok(dev)) {
 200                         int some_queue_stopped = 0;
 201                         unsigned int i;
 202
 203                         for (i = 0; i < dev->num_tx_queues; i++) {
 204                                 struct netdev_queue *txq;
 205
 206                                 txq = netdev_get_tx_queue(dev, i);
 207                                 if (netif_tx_queue_stopped(txq)) {
 208                                         some_queue_stopped = 1;
 209                                         break;
 210                                 }
 211                         }
 212
 213                         if (some_queue_stopped &&
 214                             time_after(jiffies, (dev->trans_start +
 215                                                  dev->watchdog_timeo))) {
 216                                 char drivername[64];
 217                                 WARN_ONCE(1, KERN_INFO "NETDEV WATCHDOG: %s (%s): transmit timed out\n",
 218                                        dev->name, netdev_drivername(dev, drivername, 64));
 219                                 dev->tx_timeout(dev);
 220                         }
 221                         if (!mod_timer(&dev->watchdog_timer,
 222                                        round_jiffies(jiffies +
 223                                                      dev->watchdog_timeo)))
 224                                 dev_hold(dev);
 225                 }
 226         }
 227         netif_tx_unlock(dev);
 228
 229         dev_put(dev);
 230 }
 231
 232 void __netdev_watchdog_up(struct net_device *dev)
 233 {
 234         if (dev->tx_timeout) {
 235                 if (dev->watchdog_timeo <= 0)
 236                         dev->watchdog_timeo = 5*HZ;
 237                 if (!mod_timer(&dev->watchdog_timer,
 238                                round_jiffies(jiffies + dev->watchdog_timeo)))
 239                         dev_hold(dev);
 240         }
 241 }
 242
 243 static void dev_watchdog_up(struct net_device *dev)
 244 {
 245         __netdev_watchdog_up(dev);
 246 }
 247
 248 static void dev_watchdog_down(struct net_device *dev)
 249 {
 250         netif_tx_lock_bh(dev);
 251         if (del_timer(&dev->watchdog_timer))
 252                 dev_put(dev);
 253         netif_tx_unlock_bh(dev);
 254 }
 255
 256 /**
 257  *      netif_carrier_on - set carrier
 258  *      @dev: network device
 259  *
 260  * Device has detected that carrier.
 261  */
 262 void netif_carrier_on(struct net_device *dev)
 263 {
 264         if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
 265                 linkwatch_fire_event(dev);
 266                 if (netif_running(dev))
 267                         __netdev_watchdog_up(dev);
 268         }
 269 }
 270 EXPORT_SYMBOL(netif_carrier_on);
 271
 272 /**
 273  *      netif_carrier_off - clear carrier
 274  *      @dev: network device
 275  *
 276  * Device has detected loss of carrier.
 277  */
 278 void netif_carrier_off(struct net_device *dev)
 279 {
 280         if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state))
 281                 linkwatch_fire_event(dev);
 282 }
 283 EXPORT_SYMBOL(netif_carrier_off);
 284
 285 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
 286    under all circumstances. It is difficult to invent anything faster or
 287    cheaper.
 288  */
 289
 290 static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc)
 291 {
 292         kfree_skb(skb);
 293         return NET_XMIT_CN;
 294 }
 295
 296 static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
 297 {
 298         return NULL;
 299 }
 300
 301 static int noop_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
 302 {
 303         if (net_ratelimit())
 304                 printk(KERN_DEBUG "%s deferred output. It is buggy.\n",
 305                        skb->dev->name);
 306         kfree_skb(skb);
 307         return NET_XMIT_CN;
 308 }
 309
 310 struct Qdisc_ops noop_qdisc_ops __read_mostly = {
 311         .id             =       "noop",
 312         .priv_size      =       0,
 313         .enqueue        =       noop_enqueue,
 314         .dequeue        =       noop_dequeue,
 315         .requeue        =       noop_requeue,
 316         .owner          =       THIS_MODULE,
 317 };
 318
 319 static struct netdev_queue noop_netdev_queue = {
 320         .qdisc          =       &noop_qdisc,
 321 };
 322
 323 struct Qdisc noop_qdisc = {
 324         .enqueue        =       noop_enqueue,
 325         .dequeue        =       noop_dequeue,
 326         .flags          =       TCQ_F_BUILTIN,
 327         .ops            =       &noop_qdisc_ops,
 328         .list           =       LIST_HEAD_INIT(noop_qdisc.list),
 329         .requeue.lock   =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
 330         .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
 331         .dev_queue      =       &noop_netdev_queue,
 332 };
 333 EXPORT_SYMBOL(noop_qdisc);
 334
 335 static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
 336         .id             =       "noqueue",
 337         .priv_size      =       0,
 338         .enqueue        =       noop_enqueue,
 339         .dequeue        =       noop_dequeue,
 340         .requeue        =       noop_requeue,
 341         .owner          =       THIS_MODULE,
 342 };
 343
 344 static struct Qdisc noqueue_qdisc;
 345 static struct netdev_queue noqueue_netdev_queue = {
 346         .qdisc          =       &noqueue_qdisc,
 347 };
 348
 349 static struct Qdisc noqueue_qdisc = {
 350         .enqueue        =       NULL,
 351         .dequeue        =       noop_dequeue,
 352         .flags          =       TCQ_F_BUILTIN,
 353         .ops            =       &noqueue_qdisc_ops,
 354         .list           =       LIST_HEAD_INIT(noqueue_qdisc.list),
 355         .requeue.lock   =       __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
 356         .q.lock         =       __SPIN_LOCK_UNLOCKED(noqueue_qdisc.q.lock),
 357         .dev_queue      =       &noqueue_netdev_queue,
 358 };
 359
 360
 361 static const u8 prio2band[TC_PRIO_MAX+1] =
 362         { 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 };
 363
 364 /* 3-band FIFO queue: old style, but should be a bit faster than
 365    generic prio+fifo combination.
 366  */
 367
 368 #define PFIFO_FAST_BANDS 3
 369
 370 static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
 371                                              struct Qdisc *qdisc)
 372 {
 373         struct sk_buff_head *list = qdisc_priv(qdisc);
 374         return list + prio2band[skb->priority & TC_PRIO_MAX];
 375 }
 376
 377 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
 378 {
 379         struct sk_buff_head *list = prio2list(skb, qdisc);
 380
 381         if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {
 382                 qdisc->q.qlen++;
 383                 return __qdisc_enqueue_tail(skb, qdisc, list);
 384         }
 385
 386         return qdisc_drop(skb, qdisc);
 387 }
 388
 389 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
 390 {
 391         int prio;
 392         struct sk_buff_head *list = qdisc_priv(qdisc);
 393
 394         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 395                 if (!skb_queue_empty(list + prio)) {
 396                         qdisc->q.qlen--;
 397                         return __qdisc_dequeue_head(qdisc, list + prio);
 398                 }
 399         }
 400
 401         return NULL;
 402 }
 403
 404 static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
 405 {
 406         qdisc->q.qlen++;
 407         return __qdisc_requeue(skb, qdisc, prio2list(skb, qdisc));
 408 }
 409
 410 static void pfifo_fast_reset(struct Qdisc* qdisc)
 411 {
 412         int prio;
 413         struct sk_buff_head *list = qdisc_priv(qdisc);
 414
 415         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
 416                 __qdisc_reset_queue(qdisc, list + prio);
 417
 418         qdisc->qstats.backlog = 0;
 419         qdisc->q.qlen = 0;
 420 }
 421
 422 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
 423 {
 424         struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
 425
 426         memcpy(&opt.priomap, prio2band, TC_PRIO_MAX+1);
 427         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 428         return skb->len;
 429
 430 nla_put_failure:
 431         return -1;
 432 }
 433
 434 static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
 435 {
 436         int prio;
 437         struct sk_buff_head *list = qdisc_priv(qdisc);
 438
 439         for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
 440                 skb_queue_head_init(list + prio);
 441
 442         return 0;
 443 }
 444
 445 static struct Qdisc_ops pfifo_fast_ops __read_mostly = {
 446         .id             =       "pfifo_fast",
 447         .priv_size      =       PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
 448         .enqueue        =       pfifo_fast_enqueue,
 449         .dequeue        =       pfifo_fast_dequeue,
 450         .requeue        =       pfifo_fast_requeue,
 451         .init           =       pfifo_fast_init,
 452         .reset          =       pfifo_fast_reset,
 453         .dump           =       pfifo_fast_dump,
 454         .owner          =       THIS_MODULE,
 455 };
 456
 457 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 458                           struct Qdisc_ops *ops)
 459 {
 460         void *p;
 461         struct Qdisc *sch;
 462         unsigned int size;
 463         int err = -ENOBUFS;
 464
 465         /* ensure that the Qdisc and the private data are 32-byte aligned */
 466         size = QDISC_ALIGN(sizeof(*sch));
 467         size += ops->priv_size + (QDISC_ALIGNTO - 1);
 468
 469         p = kzalloc(size, GFP_KERNEL);
 470         if (!p)
 471                 goto errout;
 472         sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
 473         sch->padded = (char *) sch - (char *) p;
 474
 475         INIT_LIST_HEAD(&sch->list);
 476         skb_queue_head_init(&sch->requeue);
 477         skb_queue_head_init(&sch->q);
 478         sch->ops = ops;
 479         sch->enqueue = ops->enqueue;
 480         sch->dequeue = ops->dequeue;
 481         sch->dev_queue = dev_queue;
 482         dev_hold(qdisc_dev(sch));
 483         atomic_set(&sch->refcnt, 1);
 484
 485         return sch;
 486 errout:
 487         return ERR_PTR(err);
 488 }
 489
 490 struct Qdisc * qdisc_create_dflt(struct net_device *dev,
 491                                  struct netdev_queue *dev_queue,
 492                                  struct Qdisc_ops *ops,
 493                                  unsigned int parentid)
 494 {
 495         struct Qdisc *sch;
 496
 497         sch = qdisc_alloc(dev_queue, ops);
 498         if (IS_ERR(sch))
 499                 goto errout;
 500         sch->parent = parentid;
 501
 502         if (!ops->init || ops->init(sch, NULL) == 0)
 503                 return sch;
 504
 505         qdisc_destroy(sch);
 506 errout:
 507         return NULL;
 508 }
 509 EXPORT_SYMBOL(qdisc_create_dflt);
 510
 511 /* Under qdisc_lock(qdisc) and BH! */
 512
 513 void qdisc_reset(struct Qdisc *qdisc)
 514 {
 515         const struct Qdisc_ops *ops = qdisc->ops;
 516
 517         if (ops->reset)
 518                 ops->reset(qdisc);
 519 }
 520 EXPORT_SYMBOL(qdisc_reset);
 521
 522 void qdisc_destroy(struct Qdisc *qdisc)
 523 {
 524         const struct Qdisc_ops  *ops = qdisc->ops;
 525
 526         if (qdisc->flags & TCQ_F_BUILTIN ||
 527             !atomic_dec_and_test(&qdisc->refcnt))
 528                 return;
 529
 530 #ifdef CONFIG_NET_SCHED
 531         qdisc_list_del(qdisc);
 532
 533         qdisc_put_stab(qdisc->stab);
 534 #endif
 535         gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
 536         if (ops->reset)
 537                 ops->reset(qdisc);
 538         if (ops->destroy)
 539                 ops->destroy(qdisc);
 540
 541         module_put(ops->owner);
 542         dev_put(qdisc_dev(qdisc));
 543
 544         __skb_queue_purge(&qdisc->requeue);
 545
 546         kfree((char *) qdisc - qdisc->padded);
 547 }
 548 EXPORT_SYMBOL(qdisc_destroy);
 549
 550 static bool dev_all_qdisc_sleeping_noop(struct net_device *dev)
 551 {
 552         unsigned int i;
 553
 554         for (i = 0; i < dev->num_tx_queues; i++) {
 555                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 556
 557                 if (txq->qdisc_sleeping != &noop_qdisc)
 558                         return false;
 559         }
 560         return true;
 561 }
 562
 563 static void attach_one_default_qdisc(struct net_device *dev,
 564                                      struct netdev_queue *dev_queue,
 565                                      void *_unused)
 566 {
 567         struct Qdisc *qdisc;
 568
 569         if (dev->tx_queue_len) {
 570                 qdisc = qdisc_create_dflt(dev, dev_queue,
 571                                           &pfifo_fast_ops, TC_H_ROOT);
 572                 if (!qdisc) {
 573                         printk(KERN_INFO "%s: activation failed\n", dev->name);
 574                         return;
 575                 }
 576         } else {
 577                 qdisc =  &noqueue_qdisc;
 578         }
 579         dev_queue->qdisc_sleeping = qdisc;
 580 }
 581
 582 static void transition_one_qdisc(struct net_device *dev,
 583                                  struct netdev_queue *dev_queue,
 584                                  void *_need_watchdog)
 585 {
 586         struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
 587         int *need_watchdog_p = _need_watchdog;
 588
 589         if (!(new_qdisc->flags & TCQ_F_BUILTIN))
 590                 clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
 591
 592         rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
 593         if (need_watchdog_p && new_qdisc != &noqueue_qdisc)
 594                 *need_watchdog_p = 1;
 595 }
 596
 597 void dev_activate(struct net_device *dev)
 598 {
 599         int need_watchdog;
 600
 601         /* No queueing discipline is attached to device;
 602            create default one i.e. pfifo_fast for devices,
 603            which need queueing and noqueue_qdisc for
 604            virtual interfaces
 605          */
 606
 607         if (dev_all_qdisc_sleeping_noop(dev))
 608                 netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
 609
 610         if (!netif_carrier_ok(dev))
 611                 /* Delay activation until next carrier-on event */
 612                 return;
 613
 614         need_watchdog = 0;
 615         netdev_for_each_tx_queue(dev, transition_one_qdisc, &need_watchdog);
 616         transition_one_qdisc(dev, &dev->rx_queue, NULL);
 617
 618         if (need_watchdog) {
 619                 dev->trans_start = jiffies;
 620                 dev_watchdog_up(dev);
 621         }
 622 }
 623
 624 static void dev_deactivate_queue(struct net_device *dev,
 625                                  struct netdev_queue *dev_queue,
 626                                  void *_qdisc_default)
 627 {
 628         struct Qdisc *qdisc_default = _qdisc_default;
 629         struct Qdisc *qdisc;
 630
 631         qdisc = dev_queue->qdisc;
 632         if (qdisc) {
 633                 spin_lock_bh(qdisc_lock(qdisc));
 634
 635                 if (!(qdisc->flags & TCQ_F_BUILTIN))
 636                         set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
 637
 638                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 639                 qdisc_reset(qdisc);
 640
 641                 spin_unlock_bh(qdisc_lock(qdisc));
 642         }
 643 }
 644
 645 static bool some_qdisc_is_busy(struct net_device *dev)
 646 {
 647         unsigned int i;
 648
 649         for (i = 0; i < dev->num_tx_queues; i++) {
 650                 struct netdev_queue *dev_queue;
 651                 spinlock_t *root_lock;
 652                 struct Qdisc *q;
 653                 int val;
 654
 655                 dev_queue = netdev_get_tx_queue(dev, i);
 656                 q = dev_queue->qdisc_sleeping;
 657                 root_lock = qdisc_lock(q);
 658
 659                 spin_lock_bh(root_lock);
 660
 661                 val = (test_bit(__QDISC_STATE_RUNNING, &q->state) ||
 662                        test_bit(__QDISC_STATE_SCHED, &q->state));
 663
 664                 spin_unlock_bh(root_lock);
 665
 666                 if (val)
 667                         return true;
 668         }
 669         return false;
 670 }
 671
 672 void dev_deactivate(struct net_device *dev)
 673 {
 674         netdev_for_each_tx_queue(dev, dev_deactivate_queue, &noop_qdisc);
 675         dev_deactivate_queue(dev, &dev->rx_queue, &noop_qdisc);
 676
 677         dev_watchdog_down(dev);
 678
 679         /* Wait for outstanding qdisc-less dev_queue_xmit calls. */
 680         synchronize_rcu();
 681
 682         /* Wait for outstanding qdisc_run calls. */
 683         while (some_qdisc_is_busy(dev))
 684                 yield();
 685 }
 686
 687 static void dev_init_scheduler_queue(struct net_device *dev,
 688                                      struct netdev_queue *dev_queue,
 689                                      void *_qdisc)
 690 {
 691         struct Qdisc *qdisc = _qdisc;
 692
 693         dev_queue->qdisc = qdisc;
 694         dev_queue->qdisc_sleeping = qdisc;
 695 }
 696
 697 void dev_init_scheduler(struct net_device *dev)
 698 {
 699         netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
 700         dev_init_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
 701
 702         setup_timer(&dev->watchdog_timer, dev_watchdog, (unsigned long)dev);
 703 }
 704
 705 static void shutdown_scheduler_queue(struct net_device *dev,
 706                                      struct netdev_queue *dev_queue,
 707                                      void *_qdisc_default)
 708 {
 709         struct Qdisc *qdisc = dev_queue->qdisc_sleeping;
 710         struct Qdisc *qdisc_default = _qdisc_default;
 711
 712         if (qdisc) {
 713                 rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 714                 dev_queue->qdisc_sleeping = qdisc_default;
 715
 716                 qdisc_destroy(qdisc);
 717         }
 718 }
 719
 720 void dev_shutdown(struct net_device *dev)
 721 {
 722         netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
 723         shutdown_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
 724         WARN_ON(timer_pending(&dev->watchdog_timer));
 725 }