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