sch_multiq.c revision f30ab418a1d3c5a8b83493e7d70d6876a74aa0ce 
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/types.h>
22#include <linux/kernel.h>
23#include <linux/string.h>
24#include <linux/errno.h>
25#include <linux/skbuff.h>
26#include <net/netlink.h>
27#include <net/pkt_sched.h>
28
29
30struct multiq_sched_data {
31	u16 bands;
32	u16 max_bands;
33	u16 curband;
34	struct tcf_proto *filter_list;
35	struct Qdisc **queues;
36};
37
38
39static struct Qdisc *
40multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
41{
42	struct multiq_sched_data *q = qdisc_priv(sch);
43	u32 band;
44	struct tcf_result res;
45	int err;
46
47	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
48	err = tc_classify(skb, q->filter_list, &res);
49#ifdef CONFIG_NET_CLS_ACT
50	switch (err) {
51	case TC_ACT_STOLEN:
52	case TC_ACT_QUEUED:
53		*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
54	case TC_ACT_SHOT:
55		return NULL;
56	}
57#endif
58	band = skb_get_queue_mapping(skb);
59
60	if (band >= q->bands)
61		return q->queues[0];
62
63	return q->queues[band];
64}
65
66static int
67multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
68{
69	struct Qdisc *qdisc;
70	int ret;
71
72	qdisc = multiq_classify(skb, sch, &ret);
73#ifdef CONFIG_NET_CLS_ACT
74	if (qdisc == NULL) {
75
76		if (ret & __NET_XMIT_BYPASS)
77			sch->qstats.drops++;
78		kfree_skb(skb);
79		return ret;
80	}
81#endif
82
83	ret = qdisc_enqueue(skb, qdisc);
84	if (ret == NET_XMIT_SUCCESS) {
85		sch->bstats.bytes += qdisc_pkt_len(skb);
86		sch->bstats.packets++;
87		sch->q.qlen++;
88		return NET_XMIT_SUCCESS;
89	}
90	if (net_xmit_drop_count(ret))
91		sch->qstats.drops++;
92	return ret;
93}
94
95static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
96{
97	struct multiq_sched_data *q = qdisc_priv(sch);
98	struct Qdisc *qdisc;
99	struct sk_buff *skb;
100	int band;
101
102	for (band = 0; band < q->bands; band++) {
103		/* cycle through bands to ensure fairness */
104		q->curband++;
105		if (q->curband >= q->bands)
106			q->curband = 0;
107
108		/* Check that target subqueue is available before
109		 * pulling an skb to avoid head-of-line blocking.
110		 */
111		if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
112			qdisc = q->queues[q->curband];
113			skb = qdisc->dequeue(qdisc);
114			if (skb) {
115				sch->q.qlen--;
116				return skb;
117			}
118		}
119	}
120	return NULL;
121
122}
123
124static 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
152static 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
173static void
174multiq_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
185static void
186multiq_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
198static 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 -EINVAL;
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 = xchg(&q->queues[i], &noop_qdisc);
218			qdisc_tree_decrease_qlen(child, child->q.qlen);
219			qdisc_destroy(child);
220		}
221	}
222
223	sch_tree_unlock(sch);
224
225	for (i = 0; i < q->bands; i++) {
226		if (q->queues[i] == &noop_qdisc) {
227			struct Qdisc *child;
228			child = qdisc_create_dflt(qdisc_dev(sch),
229						  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				child = xchg(&q->queues[i], child);
236
237				if (child != &noop_qdisc) {
238					qdisc_tree_decrease_qlen(child,
239								 child->q.qlen);
240					qdisc_destroy(child);
241				}
242				sch_tree_unlock(sch);
243			}
244		}
245	}
246	return 0;
247}
248
249static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
250{
251	struct multiq_sched_data *q = qdisc_priv(sch);
252	int i, err;
253
254	q->queues = NULL;
255
256	if (opt == NULL)
257		return -EINVAL;
258
259	q->max_bands = qdisc_dev(sch)->num_tx_queues;
260
261	q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
262	if (!q->queues)
263		return -ENOBUFS;
264	for (i = 0; i < q->max_bands; i++)
265		q->queues[i] = &noop_qdisc;
266
267	err = multiq_tune(sch,opt);
268
269	if (err)
270		kfree(q->queues);
271
272	return err;
273}
274
275static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
276{
277	struct multiq_sched_data *q = qdisc_priv(sch);
278	unsigned char *b = skb_tail_pointer(skb);
279	struct tc_multiq_qopt opt;
280
281	opt.bands = q->bands;
282	opt.max_bands = q->max_bands;
283
284	NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
285
286	return skb->len;
287
288nla_put_failure:
289	nlmsg_trim(skb, b);
290	return -1;
291}
292
293static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
294		      struct Qdisc **old)
295{
296	struct multiq_sched_data *q = qdisc_priv(sch);
297	unsigned long band = arg - 1;
298
299	if (band >= q->bands)
300		return -EINVAL;
301
302	if (new == NULL)
303		new = &noop_qdisc;
304
305	sch_tree_lock(sch);
306	*old = q->queues[band];
307	q->queues[band] = new;
308	qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
309	qdisc_reset(*old);
310	sch_tree_unlock(sch);
311
312	return 0;
313}
314
315static struct Qdisc *
316multiq_leaf(struct Qdisc *sch, unsigned long arg)
317{
318	struct multiq_sched_data *q = qdisc_priv(sch);
319	unsigned long band = arg - 1;
320
321	if (band >= q->bands)
322		return NULL;
323
324	return q->queues[band];
325}
326
327static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
328{
329	struct multiq_sched_data *q = qdisc_priv(sch);
330	unsigned long band = TC_H_MIN(classid);
331
332	if (band - 1 >= q->bands)
333		return 0;
334	return band;
335}
336
337static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
338				 u32 classid)
339{
340	return multiq_get(sch, classid);
341}
342
343
344static void multiq_put(struct Qdisc *q, unsigned long cl)
345{
346	return;
347}
348
349static int multiq_change(struct Qdisc *sch, u32 handle, u32 parent,
350			 struct nlattr **tca, unsigned long *arg)
351{
352	unsigned long cl = *arg;
353	struct multiq_sched_data *q = qdisc_priv(sch);
354
355	if (cl - 1 > q->bands)
356		return -ENOENT;
357	return 0;
358}
359
360static int multiq_delete(struct Qdisc *sch, unsigned long cl)
361{
362	struct multiq_sched_data *q = qdisc_priv(sch);
363	if (cl - 1 > q->bands)
364		return -ENOENT;
365	return 0;
366}
367
368
369static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
370			     struct sk_buff *skb, struct tcmsg *tcm)
371{
372	struct multiq_sched_data *q = qdisc_priv(sch);
373
374	if (cl - 1 > q->bands)
375		return -ENOENT;
376	tcm->tcm_handle |= TC_H_MIN(cl);
377	if (q->queues[cl-1])
378		tcm->tcm_info = q->queues[cl-1]->handle;
379	return 0;
380}
381
382static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
383				 struct gnet_dump *d)
384{
385	struct multiq_sched_data *q = qdisc_priv(sch);
386	struct Qdisc *cl_q;
387
388	cl_q = q->queues[cl - 1];
389	if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
390	    gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
391		return -1;
392
393	return 0;
394}
395
396static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
397{
398	struct multiq_sched_data *q = qdisc_priv(sch);
399	int band;
400
401	if (arg->stop)
402		return;
403
404	for (band = 0; band < q->bands; band++) {
405		if (arg->count < arg->skip) {
406			arg->count++;
407			continue;
408		}
409		if (arg->fn(sch, band+1, arg) < 0) {
410			arg->stop = 1;
411			break;
412		}
413		arg->count++;
414	}
415}
416
417static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
418{
419	struct multiq_sched_data *q = qdisc_priv(sch);
420
421	if (cl)
422		return NULL;
423	return &q->filter_list;
424}
425
426static const struct Qdisc_class_ops multiq_class_ops = {
427	.graft		=	multiq_graft,
428	.leaf		=	multiq_leaf,
429	.get		=	multiq_get,
430	.put		=	multiq_put,
431	.change		=	multiq_change,
432	.delete		=	multiq_delete,
433	.walk		=	multiq_walk,
434	.tcf_chain	=	multiq_find_tcf,
435	.bind_tcf	=	multiq_bind,
436	.unbind_tcf	=	multiq_put,
437	.dump		=	multiq_dump_class,
438	.dump_stats	=	multiq_dump_class_stats,
439};
440
441static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
442	.next		=	NULL,
443	.cl_ops		=	&multiq_class_ops,
444	.id		=	"multiq",
445	.priv_size	=	sizeof(struct multiq_sched_data),
446	.enqueue	=	multiq_enqueue,
447	.dequeue	=	multiq_dequeue,
448	.peek		=	multiq_peek,
449	.drop		=	multiq_drop,
450	.init		=	multiq_init,
451	.reset		=	multiq_reset,
452	.destroy	=	multiq_destroy,
453	.change		=	multiq_tune,
454	.dump		=	multiq_dump,
455	.owner		=	THIS_MODULE,
456};
457
458static int __init multiq_module_init(void)
459{
460	return register_qdisc(&multiq_qdisc_ops);
461}
462
463static void __exit multiq_module_exit(void)
464{
465	unregister_qdisc(&multiq_qdisc_ops);
466}
467
468module_init(multiq_module_init)
469module_exit(multiq_module_exit)
470
471MODULE_LICENSE("GPL");
472