xref: /openbmc/linux/net/sched/sch_mqprio.c (revision 612a462a)
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 
22 struct mqprio_sched {
23 	struct Qdisc		**qdiscs;
24 	int hw_offload;
25 };
26 
27 static void mqprio_destroy(struct Qdisc *sch)
28 {
29 	struct net_device *dev = qdisc_dev(sch);
30 	struct mqprio_sched *priv = qdisc_priv(sch);
31 	unsigned int ntx;
32 
33 	if (priv->qdiscs) {
34 		for (ntx = 0;
35 		     ntx < dev->num_tx_queues && priv->qdiscs[ntx];
36 		     ntx++)
37 			qdisc_destroy(priv->qdiscs[ntx]);
38 		kfree(priv->qdiscs);
39 	}
40 
41 	if (priv->hw_offload && dev->netdev_ops->ndo_setup_tc) {
42 		struct tc_mqprio_qopt mqprio = {};
43 
44 		dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_MQPRIO, &mqprio);
45 	} else {
46 		netdev_set_num_tc(dev, 0);
47 	}
48 }
49 
50 static int mqprio_parse_opt(struct net_device *dev, struct tc_mqprio_qopt *qopt)
51 {
52 	int i, j;
53 
54 	/* Verify num_tc is not out of max range */
55 	if (qopt->num_tc > TC_MAX_QUEUE)
56 		return -EINVAL;
57 
58 	/* Verify priority mapping uses valid tcs */
59 	for (i = 0; i < TC_BITMASK + 1; i++) {
60 		if (qopt->prio_tc_map[i] >= qopt->num_tc)
61 			return -EINVAL;
62 	}
63 
64 	/* Limit qopt->hw to maximum supported offload value.  Drivers have
65 	 * the option of overriding this later if they don't support the a
66 	 * given offload type.
67 	 */
68 	if (qopt->hw > TC_MQPRIO_HW_OFFLOAD_MAX)
69 		qopt->hw = TC_MQPRIO_HW_OFFLOAD_MAX;
70 
71 	/* If hardware offload is requested we will leave it to the device
72 	 * to either populate the queue counts itself or to validate the
73 	 * provided queue counts.  If ndo_setup_tc is not present then
74 	 * hardware doesn't support offload and we should return an error.
75 	 */
76 	if (qopt->hw)
77 		return dev->netdev_ops->ndo_setup_tc ? 0 : -EINVAL;
78 
79 	for (i = 0; i < qopt->num_tc; i++) {
80 		unsigned int last = qopt->offset[i] + qopt->count[i];
81 
82 		/* Verify the queue count is in tx range being equal to the
83 		 * real_num_tx_queues indicates the last queue is in use.
84 		 */
85 		if (qopt->offset[i] >= dev->real_num_tx_queues ||
86 		    !qopt->count[i] ||
87 		    last > dev->real_num_tx_queues)
88 			return -EINVAL;
89 
90 		/* Verify that the offset and counts do not overlap */
91 		for (j = i + 1; j < qopt->num_tc; j++) {
92 			if (last > qopt->offset[j])
93 				return -EINVAL;
94 		}
95 	}
96 
97 	return 0;
98 }
99 
100 static int mqprio_init(struct Qdisc *sch, struct nlattr *opt)
101 {
102 	struct net_device *dev = qdisc_dev(sch);
103 	struct mqprio_sched *priv = qdisc_priv(sch);
104 	struct netdev_queue *dev_queue;
105 	struct Qdisc *qdisc;
106 	int i, err = -EOPNOTSUPP;
107 	struct tc_mqprio_qopt *qopt = NULL;
108 
109 	BUILD_BUG_ON(TC_MAX_QUEUE != TC_QOPT_MAX_QUEUE);
110 	BUILD_BUG_ON(TC_BITMASK != TC_QOPT_BITMASK);
111 
112 	if (sch->parent != TC_H_ROOT)
113 		return -EOPNOTSUPP;
114 
115 	if (!netif_is_multiqueue(dev))
116 		return -EOPNOTSUPP;
117 
118 	if (!opt || nla_len(opt) < sizeof(*qopt))
119 		return -EINVAL;
120 
121 	qopt = nla_data(opt);
122 	if (mqprio_parse_opt(dev, qopt))
123 		return -EINVAL;
124 
125 	/* pre-allocate qdisc, attachment can't fail */
126 	priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
127 			       GFP_KERNEL);
128 	if (!priv->qdiscs)
129 		return -ENOMEM;
130 
131 	for (i = 0; i < dev->num_tx_queues; i++) {
132 		dev_queue = netdev_get_tx_queue(dev, i);
133 		qdisc = qdisc_create_dflt(dev_queue,
134 					  get_default_qdisc_ops(dev, i),
135 					  TC_H_MAKE(TC_H_MAJ(sch->handle),
136 						    TC_H_MIN(i + 1)));
137 		if (!qdisc)
138 			return -ENOMEM;
139 
140 		priv->qdiscs[i] = qdisc;
141 		qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
142 	}
143 
144 	/* If the mqprio options indicate that hardware should own
145 	 * the queue mapping then run ndo_setup_tc otherwise use the
146 	 * supplied and verified mapping
147 	 */
148 	if (qopt->hw) {
149 		struct tc_mqprio_qopt mqprio = *qopt;
150 
151 		err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_MQPRIO,
152 						    &mqprio);
153 		if (err)
154 			return err;
155 
156 		priv->hw_offload = mqprio.hw;
157 	} else {
158 		netdev_set_num_tc(dev, qopt->num_tc);
159 		for (i = 0; i < qopt->num_tc; i++)
160 			netdev_set_tc_queue(dev, i,
161 					    qopt->count[i], qopt->offset[i]);
162 	}
163 
164 	/* Always use supplied priority mappings */
165 	for (i = 0; i < TC_BITMASK + 1; i++)
166 		netdev_set_prio_tc_map(dev, i, qopt->prio_tc_map[i]);
167 
168 	sch->flags |= TCQ_F_MQROOT;
169 	return 0;
170 }
171 
172 static void mqprio_attach(struct Qdisc *sch)
173 {
174 	struct net_device *dev = qdisc_dev(sch);
175 	struct mqprio_sched *priv = qdisc_priv(sch);
176 	struct Qdisc *qdisc, *old;
177 	unsigned int ntx;
178 
179 	/* Attach underlying qdisc */
180 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
181 		qdisc = priv->qdiscs[ntx];
182 		old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
183 		if (old)
184 			qdisc_destroy(old);
185 		if (ntx < dev->real_num_tx_queues)
186 			qdisc_hash_add(qdisc, false);
187 	}
188 	kfree(priv->qdiscs);
189 	priv->qdiscs = NULL;
190 }
191 
192 static struct netdev_queue *mqprio_queue_get(struct Qdisc *sch,
193 					     unsigned long cl)
194 {
195 	struct net_device *dev = qdisc_dev(sch);
196 	unsigned long ntx = cl - 1 - netdev_get_num_tc(dev);
197 
198 	if (ntx >= dev->num_tx_queues)
199 		return NULL;
200 	return netdev_get_tx_queue(dev, ntx);
201 }
202 
203 static int mqprio_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
204 		    struct Qdisc **old)
205 {
206 	struct net_device *dev = qdisc_dev(sch);
207 	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
208 
209 	if (!dev_queue)
210 		return -EINVAL;
211 
212 	if (dev->flags & IFF_UP)
213 		dev_deactivate(dev);
214 
215 	*old = dev_graft_qdisc(dev_queue, new);
216 
217 	if (new)
218 		new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
219 
220 	if (dev->flags & IFF_UP)
221 		dev_activate(dev);
222 
223 	return 0;
224 }
225 
226 static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
227 {
228 	struct net_device *dev = qdisc_dev(sch);
229 	struct mqprio_sched *priv = qdisc_priv(sch);
230 	unsigned char *b = skb_tail_pointer(skb);
231 	struct tc_mqprio_qopt opt = { 0 };
232 	struct Qdisc *qdisc;
233 	unsigned int i;
234 
235 	sch->q.qlen = 0;
236 	memset(&sch->bstats, 0, sizeof(sch->bstats));
237 	memset(&sch->qstats, 0, sizeof(sch->qstats));
238 
239 	for (i = 0; i < dev->num_tx_queues; i++) {
240 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
241 		spin_lock_bh(qdisc_lock(qdisc));
242 		sch->q.qlen		+= qdisc->q.qlen;
243 		sch->bstats.bytes	+= qdisc->bstats.bytes;
244 		sch->bstats.packets	+= qdisc->bstats.packets;
245 		sch->qstats.backlog	+= qdisc->qstats.backlog;
246 		sch->qstats.drops	+= qdisc->qstats.drops;
247 		sch->qstats.requeues	+= qdisc->qstats.requeues;
248 		sch->qstats.overlimits	+= qdisc->qstats.overlimits;
249 		spin_unlock_bh(qdisc_lock(qdisc));
250 	}
251 
252 	opt.num_tc = netdev_get_num_tc(dev);
253 	memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map));
254 	opt.hw = priv->hw_offload;
255 
256 	for (i = 0; i < netdev_get_num_tc(dev); i++) {
257 		opt.count[i] = dev->tc_to_txq[i].count;
258 		opt.offset[i] = dev->tc_to_txq[i].offset;
259 	}
260 
261 	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
262 		goto nla_put_failure;
263 
264 	return skb->len;
265 nla_put_failure:
266 	nlmsg_trim(skb, b);
267 	return -1;
268 }
269 
270 static struct Qdisc *mqprio_leaf(struct Qdisc *sch, unsigned long cl)
271 {
272 	struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
273 
274 	if (!dev_queue)
275 		return NULL;
276 
277 	return dev_queue->qdisc_sleeping;
278 }
279 
280 static unsigned long mqprio_find(struct Qdisc *sch, u32 classid)
281 {
282 	struct net_device *dev = qdisc_dev(sch);
283 	unsigned int ntx = TC_H_MIN(classid);
284 
285 	if (ntx > dev->num_tx_queues + netdev_get_num_tc(dev))
286 		return 0;
287 	return ntx;
288 }
289 
290 static int mqprio_dump_class(struct Qdisc *sch, unsigned long cl,
291 			 struct sk_buff *skb, struct tcmsg *tcm)
292 {
293 	struct net_device *dev = qdisc_dev(sch);
294 
295 	if (cl <= netdev_get_num_tc(dev)) {
296 		tcm->tcm_parent = TC_H_ROOT;
297 		tcm->tcm_info = 0;
298 	} else {
299 		int i;
300 		struct netdev_queue *dev_queue;
301 
302 		dev_queue = mqprio_queue_get(sch, cl);
303 		tcm->tcm_parent = 0;
304 		for (i = 0; i < netdev_get_num_tc(dev); i++) {
305 			struct netdev_tc_txq tc = dev->tc_to_txq[i];
306 			int q_idx = cl - netdev_get_num_tc(dev);
307 
308 			if (q_idx > tc.offset &&
309 			    q_idx <= tc.offset + tc.count) {
310 				tcm->tcm_parent =
311 					TC_H_MAKE(TC_H_MAJ(sch->handle),
312 						  TC_H_MIN(i + 1));
313 				break;
314 			}
315 		}
316 		tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
317 	}
318 	tcm->tcm_handle |= TC_H_MIN(cl);
319 	return 0;
320 }
321 
322 static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
323 				   struct gnet_dump *d)
324 	__releases(d->lock)
325 	__acquires(d->lock)
326 {
327 	struct net_device *dev = qdisc_dev(sch);
328 
329 	if (cl <= netdev_get_num_tc(dev)) {
330 		int i;
331 		__u32 qlen = 0;
332 		struct Qdisc *qdisc;
333 		struct gnet_stats_queue qstats = {0};
334 		struct gnet_stats_basic_packed bstats = {0};
335 		struct netdev_tc_txq tc = dev->tc_to_txq[cl - 1];
336 
337 		/* Drop lock here it will be reclaimed before touching
338 		 * statistics this is required because the d->lock we
339 		 * hold here is the look on dev_queue->qdisc_sleeping
340 		 * also acquired below.
341 		 */
342 		if (d->lock)
343 			spin_unlock_bh(d->lock);
344 
345 		for (i = tc.offset; i < tc.offset + tc.count; i++) {
346 			struct netdev_queue *q = netdev_get_tx_queue(dev, i);
347 
348 			qdisc = rtnl_dereference(q->qdisc);
349 			spin_lock_bh(qdisc_lock(qdisc));
350 			qlen		  += qdisc->q.qlen;
351 			bstats.bytes      += qdisc->bstats.bytes;
352 			bstats.packets    += qdisc->bstats.packets;
353 			qstats.backlog    += qdisc->qstats.backlog;
354 			qstats.drops      += qdisc->qstats.drops;
355 			qstats.requeues   += qdisc->qstats.requeues;
356 			qstats.overlimits += qdisc->qstats.overlimits;
357 			spin_unlock_bh(qdisc_lock(qdisc));
358 		}
359 		/* Reclaim root sleeping lock before completing stats */
360 		if (d->lock)
361 			spin_lock_bh(d->lock);
362 		if (gnet_stats_copy_basic(NULL, d, NULL, &bstats) < 0 ||
363 		    gnet_stats_copy_queue(d, NULL, &qstats, qlen) < 0)
364 			return -1;
365 	} else {
366 		struct netdev_queue *dev_queue = mqprio_queue_get(sch, cl);
367 
368 		sch = dev_queue->qdisc_sleeping;
369 		if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
370 					  d, NULL, &sch->bstats) < 0 ||
371 		    gnet_stats_copy_queue(d, NULL,
372 					  &sch->qstats, sch->q.qlen) < 0)
373 			return -1;
374 	}
375 	return 0;
376 }
377 
378 static void mqprio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
379 {
380 	struct net_device *dev = qdisc_dev(sch);
381 	unsigned long ntx;
382 
383 	if (arg->stop)
384 		return;
385 
386 	/* Walk hierarchy with a virtual class per tc */
387 	arg->count = arg->skip;
388 	for (ntx = arg->skip;
389 	     ntx < dev->num_tx_queues + netdev_get_num_tc(dev);
390 	     ntx++) {
391 		if (arg->fn(sch, ntx + 1, arg) < 0) {
392 			arg->stop = 1;
393 			break;
394 		}
395 		arg->count++;
396 	}
397 }
398 
399 static const struct Qdisc_class_ops mqprio_class_ops = {
400 	.graft		= mqprio_graft,
401 	.leaf		= mqprio_leaf,
402 	.find		= mqprio_find,
403 	.walk		= mqprio_walk,
404 	.dump		= mqprio_dump_class,
405 	.dump_stats	= mqprio_dump_class_stats,
406 };
407 
408 static struct Qdisc_ops mqprio_qdisc_ops __read_mostly = {
409 	.cl_ops		= &mqprio_class_ops,
410 	.id		= "mqprio",
411 	.priv_size	= sizeof(struct mqprio_sched),
412 	.init		= mqprio_init,
413 	.destroy	= mqprio_destroy,
414 	.attach		= mqprio_attach,
415 	.dump		= mqprio_dump,
416 	.owner		= THIS_MODULE,
417 };
418 
419 static int __init mqprio_module_init(void)
420 {
421 	return register_qdisc(&mqprio_qdisc_ops);
422 }
423 
424 static void __exit mqprio_module_exit(void)
425 {
426 	unregister_qdisc(&mqprio_qdisc_ops);
427 }
428 
429 module_init(mqprio_module_init);
430 module_exit(mqprio_module_exit);
431 
432 MODULE_LICENSE("GPL");
433