xref: /openbmc/linux/net/sched/sch_mqprio.c (revision cfbb9be8)
1 /*
2  * net/sched/sch_mqprio.c
3  *
4  * Copyright (c) 2010 John Fastabend <john.r.fastabend@intel.com>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * version 2 as published by the Free Software Foundation.
9  */
10 
11 #include <linux/types.h>
12 #include <linux/slab.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/errno.h>
16 #include <linux/skbuff.h>
17 #include <linux/module.h>
18 #include <net/netlink.h>
19 #include <net/pkt_sched.h>
20 #include <net/sch_generic.h>
21 #include <net/pkt_cls.h>
22 
23 struct mqprio_sched {
24 	struct Qdisc		**qdiscs;
25 	u16 mode;
26 	u16 shaper;
27 	int hw_offload;
28 	u32 flags;
29 	u64 min_rate[TC_QOPT_MAX_QUEUE];
30 	u64 max_rate[TC_QOPT_MAX_QUEUE];
31 };
32 
33 static void mqprio_destroy(struct Qdisc *sch)
34 {
35 	struct net_device *dev = qdisc_dev(sch);
36 	struct mqprio_sched *priv = qdisc_priv(sch);
37 	unsigned int ntx;
38 
39 	if (priv->qdiscs) {
40 		for (ntx = 0;
41 		     ntx < dev->num_tx_queues && priv->qdiscs[ntx];
42 		     ntx++)
43 			qdisc_destroy(priv->qdiscs[ntx]);
44 		kfree(priv->qdiscs);
45 	}
46 
47 	if (priv->hw_offload && dev->netdev_ops->ndo_setup_tc) {
48 		struct tc_mqprio_qopt_offload mqprio = { { 0 } };
49 
50 		switch (priv->mode) {
51 		case TC_MQPRIO_MODE_DCB:
52 		case TC_MQPRIO_MODE_CHANNEL:
53 			dev->netdev_ops->ndo_setup_tc(dev,
54 						      TC_SETUP_QDISC_MQPRIO,
55 						      &mqprio);
56 			break;
57 		default:
58 			return;
59 		}
60 	} else {
61 		netdev_set_num_tc(dev, 0);
62 	}
63 }
64 
65 static int mqprio_parse_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt)
66 {
67 	int i, j;
68 
69 	/* Verify num_tc is not out of max range */
70 	if (qopt->num_tc > TC_MAX_QUEUE)
71 		return -EINVAL;
72 
73 	/* Verify priority mapping uses valid tcs */
74 	for (i = 0; i < TC_BITMASK + 1; i++) {
75 		if (qopt->prio_tc_map[i] >= qopt->num_tc)
76 			return -EINVAL;
77 	}
78 
79 	/* Limit qopt->hw to maximum supported offload value.  Drivers have
80 	 * the option of overriding this later if they don't support the a
81 	 * given offload type.
82 	 */
83 	if (qopt->hw > TC_MQPRIO_HW_OFFLOAD_MAX)
84 		qopt->hw = TC_MQPRIO_HW_OFFLOAD_MAX;
85 
86 	/* If hardware offload is requested we will leave it to the device
87 	 * to either populate the queue counts itself or to validate the
88 	 * provided queue counts.  If ndo_setup_tc is not present then
89 	 * hardware doesn't support offload and we should return an error.
90 	 */
91 	if (qopt->hw)
92 		return dev->netdev_ops->ndo_setup_tc ? 0 : -EINVAL;
93 
94 	for (i = 0; i < qopt->num_tc; i++) {
95 		unsigned int last = qopt->offset[i] + qopt->count[i];
96 
97 		/* Verify the queue count is in tx range being equal to the
98 		 * real_num_tx_queues indicates the last queue is in use.
99 		 */
100 		if (qopt->offset[i] >= dev->real_num_tx_queues ||
101 		    !qopt->count[i] ||
102 		    last > dev->real_num_tx_queues)
103 			return -EINVAL;
104 
105 		/* Verify that the offset and counts do not overlap */
106 		for (j = i + 1; j < qopt->num_tc; j++) {
107 			if (last > qopt->offset[j])
108 				return -EINVAL;
109 		}
110 	}
111 
112 	return 0;
113 }
114 
115 static const struct nla_policy mqprio_policy[TCA_MQPRIO_MAX + 1] = {
116 	[TCA_MQPRIO_MODE]	= { .len = sizeof(u16) },
117 	[TCA_MQPRIO_SHAPER]	= { .len = sizeof(u16) },
118 	[TCA_MQPRIO_MIN_RATE64]	= { .type = NLA_NESTED },
119 	[TCA_MQPRIO_MAX_RATE64]	= { .type = NLA_NESTED },
120 };
121 
122 static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
123 		      const struct nla_policy *policy, int len)
124 {
125 	int nested_len = nla_len(nla) - NLA_ALIGN(len);
126 
127 	if (nested_len >= nla_attr_size(0))
128 		return nla_parse(tb, maxtype, nla_data(nla) + NLA_ALIGN(len),
129 				 nested_len, policy, NULL);
130 
131 	memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
132 	return 0;
133 }
134 
135 static int mqprio_init(struct Qdisc *sch, struct nlattr *opt,
136 		       struct netlink_ext_ack *extack)
137 {
138 	struct net_device *dev = qdisc_dev(sch);
139 	struct mqprio_sched *priv = qdisc_priv(sch);
140 	struct netdev_queue *dev_queue;
141 	struct Qdisc *qdisc;
142 	int i, err = -EOPNOTSUPP;
143 	struct tc_mqprio_qopt *qopt = NULL;
144 	struct nlattr *tb[TCA_MQPRIO_MAX + 1];
145 	struct nlattr *attr;
146 	int rem;
147 	int len;
148 
149 	BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
150 	BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
151 
152 	if (sch->parent != TC_H_ROOT)
153 		return -EOPNOTSUPP;
154 
155 	if (!netif_is_multiqueue(dev))
156 		return -EOPNOTSUPP;
157 
158 	/* make certain can allocate enough classids to handle queues */
159 	if (dev->num_tx_queues >= TC_H_MIN_PRIORITY)
160 		return -ENOMEM;
161 
162 	if (!opt || nla_len(opt) < sizeof(*qopt))
163 		return -EINVAL;
164 
165 	qopt = nla_data(opt);
166 	if (mqprio_parse_opt(dev, qopt))
167 		return -EINVAL;
168 
169 	len = nla_len(opt) - NLA_ALIGN(sizeof(*qopt));
170 	if (len > 0) {
171 		err = parse_attr(tb, TCA_MQPRIO_MAX, opt, mqprio_policy,
172 				 sizeof(*qopt));
173 		if (err < 0)
174 			return err;
175 
176 		if (!qopt->hw)
177 			return -EINVAL;
178 
179 		if (tb[TCA_MQPRIO_MODE]) {
180 			priv->flags |= TC_MQPRIO_F_MODE;
181 			priv->mode = *(u16 *)nla_data(tb[TCA_MQPRIO_MODE]);
182 		}
183 
184 		if (tb[TCA_MQPRIO_SHAPER]) {
185 			priv->flags |= TC_MQPRIO_F_SHAPER;
186 			priv->shaper = *(u16 *)nla_data(tb[TCA_MQPRIO_SHAPER]);
187 		}
188 
189 		if (tb[TCA_MQPRIO_MIN_RATE64]) {
190 			if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE)
191 				return -EINVAL;
192 			i = 0;
193 			nla_for_each_nested(attr, tb[TCA_MQPRIO_MIN_RATE64],
194 					    rem) {
195 				if (nla_type(attr) != TCA_MQPRIO_MIN_RATE64)
196 					return -EINVAL;
197 				if (i >= qopt->num_tc)
198 					break;
199 				priv->min_rate[i] = *(u64 *)nla_data(attr);
200 				i++;
201 			}
202 			priv->flags |= TC_MQPRIO_F_MIN_RATE;
203 		}
204 
205 		if (tb[TCA_MQPRIO_MAX_RATE64]) {
206 			if (priv->shaper != TC_MQPRIO_SHAPER_BW_RATE)
207 				return -EINVAL;
208 			i = 0;
209 			nla_for_each_nested(attr, tb[TCA_MQPRIO_MAX_RATE64],
210 					    rem) {
211 				if (nla_type(attr) != TCA_MQPRIO_MAX_RATE64)
212 					return -EINVAL;
213 				if (i >= qopt->num_tc)
214 					break;
215 				priv->max_rate[i] = *(u64 *)nla_data(attr);
216 				i++;
217 			}
218 			priv->flags |= TC_MQPRIO_F_MAX_RATE;
219 		}
220 	}
221 
222 	/* pre-allocate qdisc, attachment can't fail */
223 	priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
224 			       GFP_KERNEL);
225 	if (!priv->qdiscs)
226 		return -ENOMEM;
227 
228 	for (i = 0; i < dev->num_tx_queues; i++) {
229 		dev_queue = netdev_get_tx_queue(dev, i);
230 		qdisc = qdisc_create_dflt(dev_queue,
231 					  get_default_qdisc_ops(dev, i),
232 					  TC_H_MAKE(TC_H_MAJ(sch->handle),
233 						    TC_H_MIN(i + 1)), extack);
234 		if (!qdisc)
235 			return -ENOMEM;
236 
237 		priv->qdiscs[i] = qdisc;
238 		qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
239 	}
240 
241 	/* If the mqprio options indicate that hardware should own
242 	 * the queue mapping then run ndo_setup_tc otherwise use the
243 	 * supplied and verified mapping
244 	 */
245 	if (qopt->hw) {
246 		struct tc_mqprio_qopt_offload mqprio = {.qopt = *qopt};
247 
248 		switch (priv->mode) {
249 		case TC_MQPRIO_MODE_DCB:
250 			if (priv->shaper != TC_MQPRIO_SHAPER_DCB)
251 				return -EINVAL;
252 			break;
253 		case TC_MQPRIO_MODE_CHANNEL:
254 			mqprio.flags = priv->flags;
255 			if (priv->flags & TC_MQPRIO_F_MODE)
256 				mqprio.mode = priv->mode;
257 			if (priv->flags & TC_MQPRIO_F_SHAPER)
258 				mqprio.shaper = priv->shaper;
259 			if (priv->flags & TC_MQPRIO_F_MIN_RATE)
260 				for (i = 0; i < mqprio.qopt.num_tc; i++)
261 					mqprio.min_rate[i] = priv->min_rate[i];
262 			if (priv->flags & TC_MQPRIO_F_MAX_RATE)
263 				for (i = 0; i < mqprio.qopt.num_tc; i++)
264 					mqprio.max_rate[i] = priv->max_rate[i];
265 			break;
266 		default:
267 			return -EINVAL;
268 		}
269 		err = dev->netdev_ops->ndo_setup_tc(dev,
270 						    TC_SETUP_QDISC_MQPRIO,
271 						    &mqprio);
272 		if (err)
273 			return err;
274 
275 		priv->hw_offload = mqprio.qopt.hw;
276 	} else {
277 		netdev_set_num_tc(dev, qopt->num_tc);
278 		for (i = 0; i < qopt->num_tc; i++)
279 			netdev_set_tc_queue(dev, i,
280 					    qopt->count[i], qopt->offset[i]);
281 	}
282 
283 	/* Always use supplied priority mappings */
284 	for (i = 0; i < TC_BITMASK + 1; i++)
285 		netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);
286 
287 	sch->flags |= TCQ_F_MQROOT;
288 	return 0;
289 }
290 
291 static void mqprio_attach(struct Qdisc *sch)
292 {
293 	struct net_device *dev = qdisc_dev(sch);
294 	struct mqprio_sched *priv = qdisc_priv(sch);
295 	struct Qdisc *qdisc, *old;
296 	unsigned int ntx;
297 
298 	/* Attach underlying qdisc */
299 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
300 		qdisc = priv->qdiscs[ntx];
301 		old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
302 		if (old)
303 			qdisc_destroy(old);
304 		if (ntx < dev->real_num_tx_queues)
305 			qdisc_hash_add(qdisc, false);
306 	}
307 	kfree(priv->qdiscs);
308 	priv->qdiscs = NULL;
309 }
310 
311 static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
312 					     unsigned long cl)
313 {
314 	struct net_device *dev = qdisc_dev(sch);
315 	unsigned long ntx = cl - 1;
316 
317 	if (ntx >= dev->num_tx_queues)
318 		return NULL;
319 	return netdev_get_tx_queue(dev, ntx);
320 }
321 
322 static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
323 			struct Qdisc **old, struct netlink_ext_ack *extack)
324 {
325 	struct net_device *dev = qdisc_dev(sch);
326 	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
327 
328 	if (!dev_queue)
329 		return -EINVAL;
330 
331 	if (dev->flags & IFF_UP)
332 		dev_deactivate(dev);
333 
334 	*old = dev_graft_qdisc(dev_queue, new);
335 
336 	if (new)
337 		new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
338 
339 	if (dev->flags & IFF_UP)
340 		dev_activate(dev);
341 
342 	return 0;
343 }
344 
345 static int dump_rates(struct mqprio_sched *priv,
346 		      struct tc_mqprio_qopt *opt, struct sk_buff *skb)
347 {
348 	struct nlattr *nest;
349 	int i;
350 
351 	if (priv->flags & TC_MQPRIO_F_MIN_RATE) {
352 		nest = nla_nest_start(skb, TCA_MQPRIO_MIN_RATE64);
353 		if (!nest)
354 			goto nla_put_failure;
355 
356 		for (i = 0; i < opt->num_tc; i++) {
357 			if (nla_put(skb, TCA_MQPRIO_MIN_RATE64,
358 				    sizeof(priv->min_rate[i]),
359 				    &priv->min_rate[i]))
360 				goto nla_put_failure;
361 		}
362 		nla_nest_end(skb, nest);
363 	}
364 
365 	if (priv->flags & TC_MQPRIO_F_MAX_RATE) {
366 		nest = nla_nest_start(skb, TCA_MQPRIO_MAX_RATE64);
367 		if (!nest)
368 			goto nla_put_failure;
369 
370 		for (i = 0; i < opt->num_tc; i++) {
371 			if (nla_put(skb, TCA_MQPRIO_MAX_RATE64,
372 				    sizeof(priv->max_rate[i]),
373 				    &priv->max_rate[i]))
374 				goto nla_put_failure;
375 		}
376 		nla_nest_end(skb, nest);
377 	}
378 	return 0;
379 
380 nla_put_failure:
381 	nla_nest_cancel(skb, nest);
382 	return -1;
383 }
384 
385 static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
386 {
387 	struct net_device *dev = qdisc_dev(sch);
388 	struct mqprio_sched *priv = qdisc_priv(sch);
389 	struct nlattr *nla = (struct nlattr *)skb_tail_pointer(skb);
390 	struct tc_mqprio_qopt opt = { 0 };
391 	struct Qdisc *qdisc;
392 	unsigned int ntx, tc;
393 
394 	sch->q.qlen = 0;
395 	memset(&sch->bstats, 0, sizeof(sch->bstats));
396 	memset(&sch->qstats, 0, sizeof(sch->qstats));
397 
398 	/* MQ supports lockless qdiscs. However, statistics accounting needs
399 	 * to account for all, none, or a mix of locked and unlocked child
400 	 * qdiscs. Percpu stats are added to counters in-band and locking
401 	 * qdisc totals are added at end.
402 	 */
403 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
404 		qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
405 		spin_lock_bh(qdisc_lock(qdisc));
406 
407 		if (qdisc_is_percpu_stats(qdisc)) {
408 			__u32 qlen = qdisc_qlen_sum(qdisc);
409 
410 			__gnet_stats_copy_basic(NULL, &sch->bstats,
411 						qdisc->cpu_bstats,
412 						&qdisc->bstats);
413 			__gnet_stats_copy_queue(&sch->qstats,
414 						qdisc->cpu_qstats,
415 						&qdisc->qstats, qlen);
416 		} else {
417 			sch->q.qlen		+= qdisc->q.qlen;
418 			sch->bstats.bytes	+= qdisc->bstats.bytes;
419 			sch->bstats.packets	+= qdisc->bstats.packets;
420 			sch->qstats.backlog	+= qdisc->qstats.backlog;
421 			sch->qstats.drops	+= qdisc->qstats.drops;
422 			sch->qstats.requeues	+= qdisc->qstats.requeues;
423 			sch->qstats.overlimits	+= qdisc->qstats.overlimits;
424 		}
425 
426 		spin_unlock_bh(qdisc_lock(qdisc));
427 	}
428 
429 	opt.num_tc = netdev_get_num_tc(dev);
430 	memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
431 	opt.hw = priv->hw_offload;
432 
433 	for (tc = 0; tc < netdev_get_num_tc(dev); tc++) {
434 		opt.count[tc] = dev->tc_to_txq[tc].count;
435 		opt.offset[tc] = dev->tc_to_txq[tc].offset;
436 	}
437 
438 	if (nla_put(skb, TCA_OPTIONS, NLA_ALIGN(sizeof(opt)), &opt))
439 		goto nla_put_failure;
440 
441 	if ((priv->flags & TC_MQPRIO_F_MODE) &&
442 	    nla_put_u16(skb, TCA_MQPRIO_MODE, priv->mode))
443 		goto nla_put_failure;
444 
445 	if ((priv->flags & TC_MQPRIO_F_SHAPER) &&
446 	    nla_put_u16(skb, TCA_MQPRIO_SHAPER, priv->shaper))
447 		goto nla_put_failure;
448 
449 	if ((priv->flags & TC_MQPRIO_F_MIN_RATE ||
450 	     priv->flags & TC_MQPRIO_F_MAX_RATE) &&
451 	    (dump_rates(priv, &opt, skb) != 0))
452 		goto nla_put_failure;
453 
454 	return nla_nest_end(skb, nla);
455 nla_put_failure:
456 	nlmsg_trim(skb, nla);
457 	return -1;
458 }
459 
460 static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
461 {
462 	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
463 
464 	if (!dev_queue)
465 		return NULL;
466 
467 	return dev_queue->qdisc_sleeping;
468 }
469 
470 static unsigned long mqprio_find(struct Qdisc *sch, u32 classid)
471 {
472 	struct net_device *dev = qdisc_dev(sch);
473 	unsigned int ntx = TC_H_MIN(classid);
474 
475 	/* There are essentially two regions here that have valid classid
476 	 * values. The first region will have a classid value of 1 through
477 	 * num_tx_queues. All of these are backed by actual Qdiscs.
478 	 */
479 	if (ntx < TC_H_MIN_PRIORITY)
480 		return (ntx <= dev->num_tx_queues) ? ntx : 0;
481 
482 	/* The second region represents the hardware traffic classes. These
483 	 * are represented by classid values of TC_H_MIN_PRIORITY through
484 	 * TC_H_MIN_PRIORITY + netdev_get_num_tc - 1
485 	 */
486 	return ((ntx - TC_H_MIN_PRIORITY) < netdev_get_num_tc(dev)) ? ntx : 0;
487 }
488 
489 static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
490 			 struct sk_buff *skb, struct tcmsg *tcm)
491 {
492 	if (cl < TC_H_MIN_PRIORITY) {
493 		struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
494 		struct net_device *dev = qdisc_dev(sch);
495 		int tc = netdev_txq_to_tc(dev, cl - 1);
496 
497 		tcm->tcm_parent = (tc < 0) ? 0 :
498 			TC_H_MAKE(TC_H_MAJ(sch->handle),
499 				  TC_H_MIN(tc + TC_H_MIN_PRIORITY));
500 		tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
501 	} else {
502 		tcm->tcm_parent = TC_H_ROOT;
503 		tcm->tcm_info = 0;
504 	}
505 	tcm->tcm_handle |= TC_H_MIN(cl);
506 	return 0;
507 }
508 
509 static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
510 				   struct gnet_dump *d)
511 	__releases(d->lock)
512 	__acquires(d->lock)
513 {
514 	if (cl >= TC_H_MIN_PRIORITY) {
515 		int i;
516 		__u32 qlen = 0;
517 		struct gnet_stats_queue qstats = {0};
518 		struct gnet_stats_basic_packed bstats = {0};
519 		struct net_device *dev = qdisc_dev(sch);
520 		struct netdev_tc_txq tc = dev->tc_to_txq[cl & TC_BITMASK];
521 
522 		/* Drop lock here it will be reclaimed before touching
523 		 * statistics this is required because the d->lock we
524 		 * hold here is the look on dev_queue->qdisc_sleeping
525 		 * also acquired below.
526 		 */
527 		if (d->lock)
528 			spin_unlock_bh(d->lock);
529 
530 		for (i = tc.offset; i < tc.offset + tc.count; i++) {
531 			struct netdev_queue *q = netdev_get_tx_queue(dev, i);
532 			struct Qdisc *qdisc = rtnl_dereference(q->qdisc);
533 			struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
534 			struct gnet_stats_queue __percpu *cpu_qstats = NULL;
535 
536 			spin_lock_bh(qdisc_lock(qdisc));
537 			if (qdisc_is_percpu_stats(qdisc)) {
538 				cpu_bstats = qdisc->cpu_bstats;
539 				cpu_qstats = qdisc->cpu_qstats;
540 			}
541 
542 			qlen = qdisc_qlen_sum(qdisc);
543 			__gnet_stats_copy_basic(NULL, &sch->bstats,
544 						cpu_bstats, &qdisc->bstats);
545 			__gnet_stats_copy_queue(&sch->qstats,
546 						cpu_qstats,
547 						&qdisc->qstats,
548 						qlen);
549 			spin_unlock_bh(qdisc_lock(qdisc));
550 		}
551 
552 		/* Reclaim root sleeping lock before completing stats */
553 		if (d->lock)
554 			spin_lock_bh(d->lock);
555 		if (gnet_stats_copy_basic(NULL, d, NULL, &bstats) < 0 ||
556 		    gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
557 			return -1;
558 	} else {
559 		struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
560 
561 		sch = dev_queue->qdisc_sleeping;
562 		if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
563 					  d, NULL, &sch->bstats) < 0 ||
564 		    gnet_stats_copy_queue(d, NULL,
565 					  &sch->qstats, sch->q.qlen) < 0)
566 			return -1;
567 	}
568 	return 0;
569 }
570 
571 static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
572 {
573 	struct net_device *dev = qdisc_dev(sch);
574 	unsigned long ntx;
575 
576 	if (arg->stop)
577 		return;
578 
579 	/* Walk hierarchy with a virtual class per tc */
580 	arg->count = arg->skip;
581 	for (ntx = arg->skip; ntx < netdev_get_num_tc(dev); ntx++) {
582 		if (arg->fn(sch, ntx + TC_H_MIN_PRIORITY, arg) < 0) {
583 			arg->stop = 1;
584 			return;
585 		}
586 		arg->count++;
587 	}
588 
589 	/* Pad the values and skip over unused traffic classes */
590 	if (ntx < TC_MAX_QUEUE) {
591 		arg->count = TC_MAX_QUEUE;
592 		ntx = TC_MAX_QUEUE;
593 	}
594 
595 	/* Reset offset, sort out remaining per-queue qdiscs */
596 	for (ntx -= TC_MAX_QUEUE; ntx < dev->num_tx_queues; ntx++) {
597 		if (arg->fn(sch, ntx + 1, arg) < 0) {
598 			arg->stop = 1;
599 			return;
600 		}
601 		arg->count++;
602 	}
603 }
604 
605 static struct netdev_queue *mqprio_select_queue(struct Qdisc *sch,
606 						struct tcmsg *tcm)
607 {
608 	return mqprio_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
609 }
610 
611 static const struct Qdisc_class_ops mqprio_class_ops = {
612 	.graft		= mqprio_graft,
613 	.leaf		= mqprio_leaf,
614 	.find		= mqprio_find,
615 	.walk		= mqprio_walk,
616 	.dump		= mqprio_dump_class,
617 	.dump_stats	= mqprio_dump_class_stats,
618 	.select_queue	= mqprio_select_queue,
619 };
620 
621 static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
622 	.cl_ops		= &mqprio_class_ops,
623 	.id		= "mqprio",
624 	.priv_size	= sizeof(struct mqprio_sched),
625 	.init		= mqprio_init,
626 	.destroy	= mqprio_destroy,
627 	.attach		= mqprio_attach,
628 	.dump		= mqprio_dump,
629 	.owner		= THIS_MODULE,
630 };
631 
632 static int __init mqprio_module_init(void)
633 {
634 	return register_qdisc(&mqprio_qdisc_ops);
635 }
636 
637 static void __exit mqprio_module_exit(void)
638 {
639 	unregister_qdisc(&mqprio_qdisc_ops);
640 }
641 
642 module_init(mqprio_module_init);
643 module_exit(mqprio_module_exit);
644 
645 MODULE_LICENSE("GPL");
646