xref: /openbmc/linux/net/sched/sch_multiq.c (revision 4800cd83)
1 /*
2  * Copyright (c) 2008, Intel Corporation.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms and conditions of the GNU General Public License,
6  * version 2, as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11  * more details.
12  *
13  * You should have received a copy of the GNU General Public License along with
14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
15  * Place - Suite 330, Boston, MA 02111-1307 USA.
16  *
17  * Author: Alexander Duyck <alexander.h.duyck@intel.com>
18  */
19 
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/string.h>
25 #include <linux/errno.h>
26 #include <linux/skbuff.h>
27 #include <net/netlink.h>
28 #include <net/pkt_sched.h>
29 
30 
31 struct multiq_sched_data {
32 	u16 bands;
33 	u16 max_bands;
34 	u16 curband;
35 	struct tcf_proto *filter_list;
36 	struct Qdisc **queues;
37 };
38 
39 
40 static struct Qdisc *
41 multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
42 {
43 	struct multiq_sched_data *q = qdisc_priv(sch);
44 	u32 band;
45 	struct tcf_result res;
46 	int err;
47 
48 	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
49 	err = tc_classify(skb, q->filter_list, &res);
50 #ifdef CONFIG_NET_CLS_ACT
51 	switch (err) {
52 	case TC_ACT_STOLEN:
53 	case TC_ACT_QUEUED:
54 		*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
55 	case TC_ACT_SHOT:
56 		return NULL;
57 	}
58 #endif
59 	band = skb_get_queue_mapping(skb);
60 
61 	if (band >= q->bands)
62 		return q->queues[0];
63 
64 	return q->queues[band];
65 }
66 
67 static int
68 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
69 {
70 	struct Qdisc *qdisc;
71 	int ret;
72 
73 	qdisc = multiq_classify(skb, sch, &ret);
74 #ifdef CONFIG_NET_CLS_ACT
75 	if (qdisc == NULL) {
76 
77 		if (ret & __NET_XMIT_BYPASS)
78 			sch->qstats.drops++;
79 		kfree_skb(skb);
80 		return ret;
81 	}
82 #endif
83 
84 	ret = qdisc_enqueue(skb, qdisc);
85 	if (ret == NET_XMIT_SUCCESS) {
86 		sch->q.qlen++;
87 		return NET_XMIT_SUCCESS;
88 	}
89 	if (net_xmit_drop_count(ret))
90 		sch->qstats.drops++;
91 	return ret;
92 }
93 
94 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
95 {
96 	struct multiq_sched_data *q = qdisc_priv(sch);
97 	struct Qdisc *qdisc;
98 	struct sk_buff *skb;
99 	int band;
100 
101 	for (band = 0; band < q->bands; band++) {
102 		/* cycle through bands to ensure fairness */
103 		q->curband++;
104 		if (q->curband >= q->bands)
105 			q->curband = 0;
106 
107 		/* Check that target subqueue is available before
108 		 * pulling an skb to avoid head-of-line blocking.
109 		 */
110 		if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
111 			qdisc = q->queues[q->curband];
112 			skb = qdisc->dequeue(qdisc);
113 			if (skb) {
114 				qdisc_bstats_update(sch, skb);
115 				sch->q.qlen--;
116 				return skb;
117 			}
118 		}
119 	}
120 	return NULL;
121 
122 }
123 
124 static struct sk_buff *multiq_peek(struct Qdisc *sch)
125 {
126 	struct multiq_sched_data *q = qdisc_priv(sch);
127 	unsigned int curband = q->curband;
128 	struct Qdisc *qdisc;
129 	struct sk_buff *skb;
130 	int band;
131 
132 	for (band = 0; band < q->bands; band++) {
133 		/* cycle through bands to ensure fairness */
134 		curband++;
135 		if (curband >= q->bands)
136 			curband = 0;
137 
138 		/* Check that target subqueue is available before
139 		 * pulling an skb to avoid head-of-line blocking.
140 		 */
141 		if (!__netif_subqueue_stopped(qdisc_dev(sch), curband)) {
142 			qdisc = q->queues[curband];
143 			skb = qdisc->ops->peek(qdisc);
144 			if (skb)
145 				return skb;
146 		}
147 	}
148 	return NULL;
149 
150 }
151 
152 static unsigned int multiq_drop(struct Qdisc *sch)
153 {
154 	struct multiq_sched_data *q = qdisc_priv(sch);
155 	int band;
156 	unsigned int len;
157 	struct Qdisc *qdisc;
158 
159 	for (band = q->bands-1; band >= 0; band--) {
160 		qdisc = q->queues[band];
161 		if (qdisc->ops->drop) {
162 			len = qdisc->ops->drop(qdisc);
163 			if (len != 0) {
164 				sch->q.qlen--;
165 				return len;
166 			}
167 		}
168 	}
169 	return 0;
170 }
171 
172 
173 static void
174 multiq_reset(struct Qdisc *sch)
175 {
176 	u16 band;
177 	struct multiq_sched_data *q = qdisc_priv(sch);
178 
179 	for (band = 0; band < q->bands; band++)
180 		qdisc_reset(q->queues[band]);
181 	sch->q.qlen = 0;
182 	q->curband = 0;
183 }
184 
185 static void
186 multiq_destroy(struct Qdisc *sch)
187 {
188 	int band;
189 	struct multiq_sched_data *q = qdisc_priv(sch);
190 
191 	tcf_destroy_chain(&q->filter_list);
192 	for (band = 0; band < q->bands; band++)
193 		qdisc_destroy(q->queues[band]);
194 
195 	kfree(q->queues);
196 }
197 
198 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
199 {
200 	struct multiq_sched_data *q = qdisc_priv(sch);
201 	struct tc_multiq_qopt *qopt;
202 	int i;
203 
204 	if (!netif_is_multiqueue(qdisc_dev(sch)))
205 		return -EOPNOTSUPP;
206 	if (nla_len(opt) < sizeof(*qopt))
207 		return -EINVAL;
208 
209 	qopt = nla_data(opt);
210 
211 	qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
212 
213 	sch_tree_lock(sch);
214 	q->bands = qopt->bands;
215 	for (i = q->bands; i < q->max_bands; i++) {
216 		if (q->queues[i] != &noop_qdisc) {
217 			struct Qdisc *child = q->queues[i];
218 			q->queues[i] = &noop_qdisc;
219 			qdisc_tree_decrease_qlen(child, child->q.qlen);
220 			qdisc_destroy(child);
221 		}
222 	}
223 
224 	sch_tree_unlock(sch);
225 
226 	for (i = 0; i < q->bands; i++) {
227 		if (q->queues[i] == &noop_qdisc) {
228 			struct Qdisc *child, *old;
229 			child = qdisc_create_dflt(sch->dev_queue,
230 						  &pfifo_qdisc_ops,
231 						  TC_H_MAKE(sch->handle,
232 							    i + 1));
233 			if (child) {
234 				sch_tree_lock(sch);
235 				old = q->queues[i];
236 				q->queues[i] = child;
237 
238 				if (old != &noop_qdisc) {
239 					qdisc_tree_decrease_qlen(old,
240 								 old->q.qlen);
241 					qdisc_destroy(old);
242 				}
243 				sch_tree_unlock(sch);
244 			}
245 		}
246 	}
247 	return 0;
248 }
249 
250 static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
251 {
252 	struct multiq_sched_data *q = qdisc_priv(sch);
253 	int i, err;
254 
255 	q->queues = NULL;
256 
257 	if (opt == NULL)
258 		return -EINVAL;
259 
260 	q->max_bands = qdisc_dev(sch)->num_tx_queues;
261 
262 	q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
263 	if (!q->queues)
264 		return -ENOBUFS;
265 	for (i = 0; i < q->max_bands; i++)
266 		q->queues[i] = &noop_qdisc;
267 
268 	err = multiq_tune(sch,opt);
269 
270 	if (err)
271 		kfree(q->queues);
272 
273 	return err;
274 }
275 
276 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
277 {
278 	struct multiq_sched_data *q = qdisc_priv(sch);
279 	unsigned char *b = skb_tail_pointer(skb);
280 	struct tc_multiq_qopt opt;
281 
282 	opt.bands = q->bands;
283 	opt.max_bands = q->max_bands;
284 
285 	NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
286 
287 	return skb->len;
288 
289 nla_put_failure:
290 	nlmsg_trim(skb, b);
291 	return -1;
292 }
293 
294 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
295 		      struct Qdisc **old)
296 {
297 	struct multiq_sched_data *q = qdisc_priv(sch);
298 	unsigned long band = arg - 1;
299 
300 	if (new == NULL)
301 		new = &noop_qdisc;
302 
303 	sch_tree_lock(sch);
304 	*old = q->queues[band];
305 	q->queues[band] = new;
306 	qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
307 	qdisc_reset(*old);
308 	sch_tree_unlock(sch);
309 
310 	return 0;
311 }
312 
313 static struct Qdisc *
314 multiq_leaf(struct Qdisc *sch, unsigned long arg)
315 {
316 	struct multiq_sched_data *q = qdisc_priv(sch);
317 	unsigned long band = arg - 1;
318 
319 	return q->queues[band];
320 }
321 
322 static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
323 {
324 	struct multiq_sched_data *q = qdisc_priv(sch);
325 	unsigned long band = TC_H_MIN(classid);
326 
327 	if (band - 1 >= q->bands)
328 		return 0;
329 	return band;
330 }
331 
332 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
333 				 u32 classid)
334 {
335 	return multiq_get(sch, classid);
336 }
337 
338 
339 static void multiq_put(struct Qdisc *q, unsigned long cl)
340 {
341 }
342 
343 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
344 			     struct sk_buff *skb, struct tcmsg *tcm)
345 {
346 	struct multiq_sched_data *q = qdisc_priv(sch);
347 
348 	tcm->tcm_handle |= TC_H_MIN(cl);
349 	tcm->tcm_info = q->queues[cl-1]->handle;
350 	return 0;
351 }
352 
353 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
354 				 struct gnet_dump *d)
355 {
356 	struct multiq_sched_data *q = qdisc_priv(sch);
357 	struct Qdisc *cl_q;
358 
359 	cl_q = q->queues[cl - 1];
360 	cl_q->qstats.qlen = cl_q->q.qlen;
361 	if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
362 	    gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
363 		return -1;
364 
365 	return 0;
366 }
367 
368 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
369 {
370 	struct multiq_sched_data *q = qdisc_priv(sch);
371 	int band;
372 
373 	if (arg->stop)
374 		return;
375 
376 	for (band = 0; band < q->bands; band++) {
377 		if (arg->count < arg->skip) {
378 			arg->count++;
379 			continue;
380 		}
381 		if (arg->fn(sch, band+1, arg) < 0) {
382 			arg->stop = 1;
383 			break;
384 		}
385 		arg->count++;
386 	}
387 }
388 
389 static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
390 {
391 	struct multiq_sched_data *q = qdisc_priv(sch);
392 
393 	if (cl)
394 		return NULL;
395 	return &q->filter_list;
396 }
397 
398 static const struct Qdisc_class_ops multiq_class_ops = {
399 	.graft		=	multiq_graft,
400 	.leaf		=	multiq_leaf,
401 	.get		=	multiq_get,
402 	.put		=	multiq_put,
403 	.walk		=	multiq_walk,
404 	.tcf_chain	=	multiq_find_tcf,
405 	.bind_tcf	=	multiq_bind,
406 	.unbind_tcf	=	multiq_put,
407 	.dump		=	multiq_dump_class,
408 	.dump_stats	=	multiq_dump_class_stats,
409 };
410 
411 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
412 	.next		=	NULL,
413 	.cl_ops		=	&multiq_class_ops,
414 	.id		=	"multiq",
415 	.priv_size	=	sizeof(struct multiq_sched_data),
416 	.enqueue	=	multiq_enqueue,
417 	.dequeue	=	multiq_dequeue,
418 	.peek		=	multiq_peek,
419 	.drop		=	multiq_drop,
420 	.init		=	multiq_init,
421 	.reset		=	multiq_reset,
422 	.destroy	=	multiq_destroy,
423 	.change		=	multiq_tune,
424 	.dump		=	multiq_dump,
425 	.owner		=	THIS_MODULE,
426 };
427 
428 static int __init multiq_module_init(void)
429 {
430 	return register_qdisc(&multiq_qdisc_ops);
431 }
432 
433 static void __exit multiq_module_exit(void)
434 {
435 	unregister_qdisc(&multiq_qdisc_ops);
436 }
437 
438 module_init(multiq_module_init)
439 module_exit(multiq_module_exit)
440 
441 MODULE_LICENSE("GPL");
442