aboutsummaryrefslogtreecommitdiff
path: root/net/mac80211/wme.c
blob: cfa8fbb0736a3bab7fa0f1f9bb20b5b6db386bfc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
/*
 * Copyright 2004, Instant802 Networks, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/types.h>
#include <net/ip.h>
#include <net/pkt_sched.h>

#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "wme.h"

/* maximum number of hardware queues we support. */
#define QD_MAX_QUEUES (IEEE80211_MAX_AMPDU_QUEUES + IEEE80211_MAX_QUEUES)
/* current number of hardware queues we support. */
#define QD_NUM(hw) ((hw)->queues + (hw)->ampdu_queues)

/*
 * Default mapping in classifier to work with default
 * queue setup.
 */
const int ieee802_1d_to_ac[8] = { 2, 3, 3, 2, 1, 1, 0, 0 };

struct ieee80211_sched_data
{
	unsigned long qdisc_pool[BITS_TO_LONGS(QD_MAX_QUEUES)];
	struct tcf_proto *filter_list;
	struct Qdisc *queues[QD_MAX_QUEUES];
	struct sk_buff_head requeued[QD_MAX_QUEUES];
};

static const char llc_ip_hdr[8] = {0xAA, 0xAA, 0x3, 0, 0, 0, 0x08, 0};

/* given a data frame determine the 802.1p/1d tag to use */
static inline unsigned classify_1d(struct sk_buff *skb, struct Qdisc *qd)
{
	struct iphdr *ip;
	int dscp;
	int offset;

	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct tcf_result res = { -1, 0 };

	/* if there is a user set filter list, call out to that */
	if (q->filter_list) {
		tc_classify(skb, q->filter_list, &res);
		if (res.class != -1)
			return res.class;
	}

	/* skb->priority values from 256->263 are magic values to
	 * directly indicate a specific 802.1d priority.
	 * This is used to allow 802.1d priority to be passed directly in
	 * from VLAN tags, etc. */
	if (skb->priority >= 256 && skb->priority <= 263)
		return skb->priority - 256;

	/* check there is a valid IP header present */
	offset = ieee80211_get_hdrlen_from_skb(skb);
	if (skb->len < offset + sizeof(llc_ip_hdr) + sizeof(*ip) ||
	    memcmp(skb->data + offset, llc_ip_hdr, sizeof(llc_ip_hdr)))
		return 0;

	ip = (struct iphdr *) (skb->data + offset + sizeof(llc_ip_hdr));

	dscp = ip->tos & 0xfc;
	if (dscp & 0x1c)
		return 0;
	return dscp >> 5;
}


static inline int wme_downgrade_ac(struct sk_buff *skb)
{
	switch (skb->priority) {
	case 6:
	case 7:
		skb->priority = 5; /* VO -> VI */
		return 0;
	case 4:
	case 5:
		skb->priority = 3; /* VI -> BE */
		return 0;
	case 0:
	case 3:
		skb->priority = 2; /* BE -> BK */
		return 0;
	default:
		return -1;
	}
}


/* positive return value indicates which queue to use
 * negative return value indicates to drop the frame */
static int classify80211(struct sk_buff *skb, struct Qdisc *qd)
{
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;

	if (!ieee80211_is_data(hdr->frame_control)) {
		/* management frames go on AC_VO queue, but are sent
		* without QoS control fields */
		return 0;
	}

	if (0 /* injected */) {
		/* use AC from radiotap */
	}

	if (!ieee80211_is_data_qos(hdr->frame_control)) {
		skb->priority = 0; /* required for correct WPA/11i MIC */
		return ieee802_1d_to_ac[skb->priority];
	}

	/* use the data classifier to determine what 802.1d tag the
	 * data frame has */
	skb->priority = classify_1d(skb, qd);

	/* in case we are a client verify acm is not set for this ac */
	while (unlikely(local->wmm_acm & BIT(skb->priority))) {
		if (wme_downgrade_ac(skb)) {
			/* No AC with lower priority has acm=0, drop packet. */
			return -1;
		}
	}

	/* look up which queue to use for frames with this 1d tag */
	return ieee802_1d_to_ac[skb->priority];
}


static int wme_qdiscop_enqueue(struct sk_buff *skb, struct Qdisc* qd)
{
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct Qdisc *qdisc;
	struct sta_info *sta;
	int err, queue;
	u8 tid;

	if (info->flags & IEEE80211_TX_CTL_REQUEUE) {
		queue = skb_get_queue_mapping(skb);
		rcu_read_lock();
		sta = sta_info_get(local, hdr->addr1);
		tid = skb->priority & QOS_CONTROL_TAG1D_MASK;
		if (sta) {
			int ampdu_queue = sta->tid_to_tx_q[tid];
			if ((ampdu_queue < QD_NUM(hw)) &&
			    test_bit(ampdu_queue, q->qdisc_pool)) {
				queue = ampdu_queue;
				info->flags |= IEEE80211_TX_CTL_AMPDU;
			} else {
				info->flags &= ~IEEE80211_TX_CTL_AMPDU;
			}
		}
		rcu_read_unlock();
		skb_queue_tail(&q->requeued[queue], skb);
		qd->q.qlen++;
		return 0;
	}

	queue = classify80211(skb, qd);

	if (unlikely(queue >= local->hw.queues))
		queue = local->hw.queues - 1;

	/* now we know the 1d priority, fill in the QoS header if there is one
	 */
	if (ieee80211_is_data_qos(hdr->frame_control)) {
		u8 *p = ieee80211_get_qos_ctl(hdr);
		u8 ack_policy = 0;
		tid = skb->priority & QOS_CONTROL_TAG1D_MASK;
		if (local->wifi_wme_noack_test)
			ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
					QOS_CONTROL_ACK_POLICY_SHIFT;
		/* qos header is 2 bytes, second reserved */
		*p++ = ack_policy | tid;
		*p = 0;

		rcu_read_lock();

		sta = sta_info_get(local, hdr->addr1);
		if (sta) {
			int ampdu_queue = sta->tid_to_tx_q[tid];
			if ((ampdu_queue < QD_NUM(hw)) &&
			    test_bit(ampdu_queue, q->qdisc_pool)) {
				queue = ampdu_queue;
				info->flags |= IEEE80211_TX_CTL_AMPDU;
			} else {
				info->flags &= ~IEEE80211_TX_CTL_AMPDU;
			}
		}

		rcu_read_unlock();
	}

	if (unlikely(queue < 0)) {
			kfree_skb(skb);
			err = NET_XMIT_DROP;
	} else {
		tid = skb->priority & QOS_CONTROL_TAG1D_MASK;
		skb_set_queue_mapping(skb, queue);
		qdisc = q->queues[queue];
		err = qdisc->enqueue(skb, qdisc);
		if (err == NET_XMIT_SUCCESS) {
			qd->q.qlen++;
			qd->bstats.bytes += skb->len;
			qd->bstats.packets++;
			return NET_XMIT_SUCCESS;
		}
	}
	qd->qstats.drops++;
	return err;
}


/* TODO: clean up the cases where master_hard_start_xmit
 * returns non 0 - it shouldn't ever do that. Once done we
 * can remove this function */
static int wme_qdiscop_requeue(struct sk_buff *skb, struct Qdisc* qd)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct Qdisc *qdisc;
	int err;

	/* we recorded which queue to use earlier! */
	qdisc = q->queues[skb_get_queue_mapping(skb)];

	if ((err = qdisc->ops->requeue(skb, qdisc)) == 0) {
		qd->q.qlen++;
		return 0;
	}
	qd->qstats.drops++;
	return err;
}


static struct sk_buff *wme_qdiscop_dequeue(struct Qdisc* qd)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct net_device *dev = qd->dev;
	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	struct sk_buff *skb;
	struct Qdisc *qdisc;
	int queue;

	/* check all the h/w queues in numeric/priority order */
	for (queue = 0; queue < QD_NUM(hw); queue++) {
		/* see if there is room in this hardware queue */
		if (__netif_subqueue_stopped(local->mdev, queue) ||
		    !test_bit(queue, q->qdisc_pool))
			continue;

		/* there is space - try and get a frame */
		skb = skb_dequeue(&q->requeued[queue]);
		if (skb) {
			qd->q.qlen--;
			return skb;
		}

		qdisc = q->queues[queue];
		skb = qdisc->dequeue(qdisc);
		if (skb) {
			qd->q.qlen--;
			return skb;
		}
	}
	/* returning a NULL here when all the h/w queues are full means we
	 * never need to call netif_stop_queue in the driver */
	return NULL;
}


static void wme_qdiscop_reset(struct Qdisc* qd)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	int queue;

	/* QUESTION: should we have some hardware flush functionality here? */

	for (queue = 0; queue < QD_NUM(hw); queue++) {
		skb_queue_purge(&q->requeued[queue]);
		qdisc_reset(q->queues[queue]);
	}
	qd->q.qlen = 0;
}


static void wme_qdiscop_destroy(struct Qdisc* qd)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	int queue;

	tcf_destroy_chain(q->filter_list);
	q->filter_list = NULL;

	for (queue = 0; queue < QD_NUM(hw); queue++) {
		skb_queue_purge(&q->requeued[queue]);
		qdisc_destroy(q->queues[queue]);
		q->queues[queue] = &noop_qdisc;
	}
}


/* called whenever parameters are updated on existing qdisc */
static int wme_qdiscop_tune(struct Qdisc *qd, struct nlattr *opt)
{
	return 0;
}


/* called during initial creation of qdisc on device */
static int wme_qdiscop_init(struct Qdisc *qd, struct nlattr *opt)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct net_device *dev = qd->dev;
	struct ieee80211_local *local;
	struct ieee80211_hw *hw;
	int err = 0, i;

	/* check that device is a mac80211 device */
	if (!dev->ieee80211_ptr ||
	    dev->ieee80211_ptr->wiphy->privid != mac80211_wiphy_privid)
		return -EINVAL;

	local = wdev_priv(dev->ieee80211_ptr);
	hw = &local->hw;

	/* only allow on master dev */
	if (dev != local->mdev)
		return -EINVAL;

	/* ensure that we are root qdisc */
	if (qd->parent != TC_H_ROOT)
		return -EINVAL;

	if (qd->flags & TCQ_F_INGRESS)
		return -EINVAL;

	/* if options were passed in, set them */
	if (opt)
		err = wme_qdiscop_tune(qd, opt);

	/* create child queues */
	for (i = 0; i < QD_NUM(hw); i++) {
		skb_queue_head_init(&q->requeued[i]);
		q->queues[i] = qdisc_create_dflt(qd->dev, &pfifo_qdisc_ops,
						 qd->handle);
		if (!q->queues[i]) {
			q->queues[i] = &noop_qdisc;
			printk(KERN_ERR "%s child qdisc %i creation failed\n",
			       dev->name, i);
		}
	}

	/* non-aggregation queues: reserve/mark as used */
	for (i = 0; i < local->hw.queues; i++)
		set_bit(i, q->qdisc_pool);

	return err;
}

static int wme_qdiscop_dump(struct Qdisc *qd, struct sk_buff *skb)
{
	return -1;
}


static int wme_classop_graft(struct Qdisc *qd, unsigned long arg,
			     struct Qdisc *new, struct Qdisc **old)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	unsigned long queue = arg - 1;

	if (queue >= QD_NUM(hw))
		return -EINVAL;

	if (!new)
		new = &noop_qdisc;

	sch_tree_lock(qd);
	*old = q->queues[queue];
	q->queues[queue] = new;
	qdisc_reset(*old);
	sch_tree_unlock(qd);

	return 0;
}


static struct Qdisc *
wme_classop_leaf(struct Qdisc *qd, unsigned long arg)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	unsigned long queue = arg - 1;

	if (queue >= QD_NUM(hw))
		return NULL;

	return q->queues[queue];
}


static unsigned long wme_classop_get(struct Qdisc *qd, u32 classid)
{
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	unsigned long queue = TC_H_MIN(classid);

	if (queue - 1 >= QD_NUM(hw))
		return 0;

	return queue;
}


static unsigned long wme_classop_bind(struct Qdisc *qd, unsigned long parent,
				      u32 classid)
{
	return wme_classop_get(qd, classid);
}


static void wme_classop_put(struct Qdisc *q, unsigned long cl)
{
}


static int wme_classop_change(struct Qdisc *qd, u32 handle, u32 parent,
			      struct nlattr **tca, unsigned long *arg)
{
	unsigned long cl = *arg;
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;

	if (cl - 1 > QD_NUM(hw))
		return -ENOENT;

	/* TODO: put code to program hardware queue parameters here,
	 * to allow programming from tc command line */

	return 0;
}


/* we don't support deleting hardware queues
 * when we add WMM-SA support - TSPECs may be deleted here */
static int wme_classop_delete(struct Qdisc *qd, unsigned long cl)
{
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;

	if (cl - 1 > QD_NUM(hw))
		return -ENOENT;
	return 0;
}


static int wme_classop_dump_class(struct Qdisc *qd, unsigned long cl,
				  struct sk_buff *skb, struct tcmsg *tcm)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;

	if (cl - 1 > QD_NUM(hw))
		return -ENOENT;
	tcm->tcm_handle = TC_H_MIN(cl);
	tcm->tcm_parent = qd->handle;
	tcm->tcm_info = q->queues[cl-1]->handle; /* do we need this? */
	return 0;
}


static void wme_classop_walk(struct Qdisc *qd, struct qdisc_walker *arg)
{
	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
	struct ieee80211_hw *hw = &local->hw;
	int queue;

	if (arg->stop)
		return;

	for (queue = 0; queue < QD_NUM(hw); queue++) {
		if (arg->count < arg->skip) {
			arg->count++;
			continue;
		}
		/* we should return classids for our internal queues here
		 * as well as the external ones */
		if (arg->fn(qd, queue+1, arg) < 0) {
			arg->stop = 1;
			break;
		}
		arg->count++;
	}
}


static struct tcf_proto ** wme_classop_find_tcf(struct Qdisc *qd,
						unsigned long cl)
{
	struct ieee80211_sched_data *q = qdisc_priv(qd);

	if (cl)
		return NULL;

	return &q->filter_list;
}


/* this qdisc is classful (i.e. has classes, some of which may have leaf qdiscs attached)
 * - these are the operations on the classes */
static const struct Qdisc_class_ops class_ops =
{
	.graft = wme_classop_graft,
	.leaf = wme_classop_leaf,

	.get = wme_classop_get,
	.put = wme_classop_put,
	.change = wme_classop_change,
	.delete = wme_classop_delete,
	.walk = wme_classop_walk,

	.tcf_chain = wme_classop_find_tcf,
	.bind_tcf = wme_classop_bind,
	.unbind_tcf = wme_classop_put,

	.dump = wme_classop_dump_class,
};


/* queueing discipline operations */
static struct Qdisc_ops wme_qdisc_ops __read_mostly =
{
	.next = NULL,
	.cl_ops = &class_ops,
	.id = "ieee80211",
	.priv_size = sizeof(struct ieee80211_sched_data),

	.enqueue = wme_qdiscop_enqueue,
	.dequeue = wme_qdiscop_dequeue,
	.requeue = wme_qdiscop_requeue,
	.drop = NULL, /* drop not needed since we are always the root qdisc */

	.init = wme_qdiscop_init,
	.reset = wme_qdiscop_reset,
	.destroy = wme_qdiscop_destroy,
	.change = wme_qdiscop_tune,

	.dump = wme_qdiscop_dump,
};


void ieee80211_install_qdisc(struct net_device *dev)
{
	struct Qdisc *qdisc;

	qdisc = qdisc_create_dflt(dev, &wme_qdisc_ops, TC_H_ROOT);
	if (!qdisc) {
		printk(KERN_ERR "%s: qdisc installation failed\n", dev->name);
		return;
	}

	/* same handle as would be allocated by qdisc_alloc_handle() */
	qdisc->handle = 0x80010000;

	qdisc_lock_tree(dev);
	list_add_tail(&qdisc->list, &dev->qdisc_list);
	dev->qdisc_sleeping = qdisc;
	qdisc_unlock_tree(dev);
}


int ieee80211_qdisc_installed(struct net_device *dev)
{
	return dev->qdisc_sleeping->ops == &wme_qdisc_ops;
}


int ieee80211_wme_register(void)
{
	return register_qdisc(&wme_qdisc_ops);
}


void ieee80211_wme_unregister(void)
{
	unregister_qdisc(&wme_qdisc_ops);
}

int ieee80211_ht_agg_queue_add(struct ieee80211_local *local,
			struct sta_info *sta, u16 tid)
{
	int i;
	struct ieee80211_sched_data *q =
			qdisc_priv(local->mdev->qdisc_sleeping);
	DECLARE_MAC_BUF(mac);

	/* prepare the filter and save it for the SW queue
	 * matching the received HW queue */

	if (!local->hw.ampdu_queues)
		return -EPERM;

	/* try to get a Qdisc from the pool */
	for (i = local->hw.queues; i < QD_NUM(&local->hw); i++)
		if (!test_and_set_bit(i, q->qdisc_pool)) {
			ieee80211_stop_queue(local_to_hw(local), i);
			sta->tid_to_tx_q[tid] = i;

			/* IF there are already pending packets
			 * on this tid first we need to drain them
			 * on the previous queue
			 * since HT is strict in order */
#ifdef CONFIG_MAC80211_HT_DEBUG
			if (net_ratelimit())
				printk(KERN_DEBUG "allocated aggregation queue"
					" %d tid %d addr %s pool=0x%lX\n",
					i, tid, print_mac(mac, sta->addr),
					q->qdisc_pool[0]);
#endif /* CONFIG_MAC80211_HT_DEBUG */
			return 0;
		}

	return -EAGAIN;
}

/**
 * the caller needs to hold local->mdev->queue_lock
 */
void ieee80211_ht_agg_queue_remove(struct ieee80211_local *local,
				   struct sta_info *sta, u16 tid,
				   u8 requeue)
{
	struct ieee80211_hw *hw = &local->hw;
	struct ieee80211_sched_data *q =
		qdisc_priv(local->mdev->qdisc_sleeping);
	int agg_queue = sta->tid_to_tx_q[tid];

	/* return the qdisc to the pool */
	clear_bit(agg_queue, q->qdisc_pool);
	sta->tid_to_tx_q[tid] = QD_NUM(hw);

	if (requeue)
		ieee80211_requeue(local, agg_queue);
	else
		q->queues[agg_queue]->ops->reset(q->queues[agg_queue]);
}

void ieee80211_requeue(struct ieee80211_local *local, int queue)
{
	struct Qdisc *root_qd = local->mdev->qdisc_sleeping;
	struct ieee80211_sched_data *q = qdisc_priv(root_qd);
	struct Qdisc *qdisc = q->queues[queue];
	struct sk_buff *skb = NULL;
	u32 len;

	if (!qdisc || !qdisc->dequeue)
		return;

	printk(KERN_DEBUG "requeue: qlen = %d\n", qdisc->q.qlen);
	for (len = qdisc->q.qlen; len > 0; len--) {
		skb = qdisc->dequeue(qdisc);
		root_qd->q.qlen--;
		/* packet will be classified again and */
		/* skb->packet_data->queue will be overridden if needed */
		if (skb)
			wme_qdiscop_enqueue(skb, root_qd);
	}
}