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
31struct 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
40static struct Qdisc *
41multiq_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
67static int
68multiq_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
94static 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_xmit_stopped(
111		    netdev_get_tx_queue(qdisc_dev(sch), q->curband))) {
112			qdisc = q->queues[q->curband];
113			skb = qdisc->dequeue(qdisc);
114			if (skb) {
115				qdisc_bstats_update(sch, skb);
116				sch->q.qlen--;
117				return skb;
118			}
119		}
120	}
121	return NULL;
122
123}
124
125static struct sk_buff *multiq_peek(struct Qdisc *sch)
126{
127	struct multiq_sched_data *q = qdisc_priv(sch);
128	unsigned int curband = q->curband;
129	struct Qdisc *qdisc;
130	struct sk_buff *skb;
131	int band;
132
133	for (band = 0; band < q->bands; band++) {
134		/* cycle through bands to ensure fairness */
135		curband++;
136		if (curband >= q->bands)
137			curband = 0;
138
139		/* Check that target subqueue is available before
140		 * pulling an skb to avoid head-of-line blocking.
141		 */
142		if (!netif_xmit_stopped(
143		    netdev_get_tx_queue(qdisc_dev(sch), curband))) {
144			qdisc = q->queues[curband];
145			skb = qdisc->ops->peek(qdisc);
146			if (skb)
147				return skb;
148		}
149	}
150	return NULL;
151
152}
153
154static unsigned int multiq_drop(struct Qdisc *sch)
155{
156	struct multiq_sched_data *q = qdisc_priv(sch);
157	int band;
158	unsigned int len;
159	struct Qdisc *qdisc;
160
161	for (band = q->bands - 1; band >= 0; band--) {
162		qdisc = q->queues[band];
163		if (qdisc->ops->drop) {
164			len = qdisc->ops->drop(qdisc);
165			if (len != 0) {
166				sch->q.qlen--;
167				return len;
168			}
169		}
170	}
171	return 0;
172}
173
174
175static void
176multiq_reset(struct Qdisc *sch)
177{
178	u16 band;
179	struct multiq_sched_data *q = qdisc_priv(sch);
180
181	for (band = 0; band < q->bands; band++)
182		qdisc_reset(q->queues[band]);
183	sch->q.qlen = 0;
184	q->curband = 0;
185}
186
187static void
188multiq_destroy(struct Qdisc *sch)
189{
190	int band;
191	struct multiq_sched_data *q = qdisc_priv(sch);
192
193	tcf_destroy_chain(&q->filter_list);
194	for (band = 0; band < q->bands; band++)
195		qdisc_destroy(q->queues[band]);
196
197	kfree(q->queues);
198}
199
200static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
201{
202	struct multiq_sched_data *q = qdisc_priv(sch);
203	struct tc_multiq_qopt *qopt;
204	int i;
205
206	if (!netif_is_multiqueue(qdisc_dev(sch)))
207		return -EOPNOTSUPP;
208	if (nla_len(opt) < sizeof(*qopt))
209		return -EINVAL;
210
211	qopt = nla_data(opt);
212
213	qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
214
215	sch_tree_lock(sch);
216	q->bands = qopt->bands;
217	for (i = q->bands; i < q->max_bands; i++) {
218		if (q->queues[i] != &noop_qdisc) {
219			struct Qdisc *child = q->queues[i];
220			q->queues[i] = &noop_qdisc;
221			qdisc_tree_decrease_qlen(child, child->q.qlen);
222			qdisc_destroy(child);
223		}
224	}
225
226	sch_tree_unlock(sch);
227
228	for (i = 0; i < q->bands; i++) {
229		if (q->queues[i] == &noop_qdisc) {
230			struct Qdisc *child, *old;
231			child = qdisc_create_dflt(sch->dev_queue,
232						  &pfifo_qdisc_ops,
233						  TC_H_MAKE(sch->handle,
234							    i + 1));
235			if (child) {
236				sch_tree_lock(sch);
237				old = q->queues[i];
238				q->queues[i] = child;
239
240				if (old != &noop_qdisc) {
241					qdisc_tree_decrease_qlen(old,
242								 old->q.qlen);
243					qdisc_destroy(old);
244				}
245				sch_tree_unlock(sch);
246			}
247		}
248	}
249	return 0;
250}
251
252static int multiq_init(struct Qdisc *sch, struct nlattr *opt)
253{
254	struct multiq_sched_data *q = qdisc_priv(sch);
255	int i, err;
256
257	q->queues = NULL;
258
259	if (opt == NULL)
260		return -EINVAL;
261
262	q->max_bands = qdisc_dev(sch)->num_tx_queues;
263
264	q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
265	if (!q->queues)
266		return -ENOBUFS;
267	for (i = 0; i < q->max_bands; i++)
268		q->queues[i] = &noop_qdisc;
269
270	err = multiq_tune(sch, opt);
271
272	if (err)
273		kfree(q->queues);
274
275	return err;
276}
277
278static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
279{
280	struct multiq_sched_data *q = qdisc_priv(sch);
281	unsigned char *b = skb_tail_pointer(skb);
282	struct tc_multiq_qopt opt;
283
284	opt.bands = q->bands;
285	opt.max_bands = q->max_bands;
286
287	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
288		goto nla_put_failure;
289
290	return skb->len;
291
292nla_put_failure:
293	nlmsg_trim(skb, b);
294	return -1;
295}
296
297static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
298		      struct Qdisc **old)
299{
300	struct multiq_sched_data *q = qdisc_priv(sch);
301	unsigned long band = arg - 1;
302
303	if (new == NULL)
304		new = &noop_qdisc;
305
306	sch_tree_lock(sch);
307	*old = q->queues[band];
308	q->queues[band] = new;
309	qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
310	qdisc_reset(*old);
311	sch_tree_unlock(sch);
312
313	return 0;
314}
315
316static struct Qdisc *
317multiq_leaf(struct Qdisc *sch, unsigned long arg)
318{
319	struct multiq_sched_data *q = qdisc_priv(sch);
320	unsigned long band = arg - 1;
321
322	return q->queues[band];
323}
324
325static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
326{
327	struct multiq_sched_data *q = qdisc_priv(sch);
328	unsigned long band = TC_H_MIN(classid);
329
330	if (band - 1 >= q->bands)
331		return 0;
332	return band;
333}
334
335static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
336				 u32 classid)
337{
338	return multiq_get(sch, classid);
339}
340
341
342static void multiq_put(struct Qdisc *q, unsigned long cl)
343{
344}
345
346static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
347			     struct sk_buff *skb, struct tcmsg *tcm)
348{
349	struct multiq_sched_data *q = qdisc_priv(sch);
350
351	tcm->tcm_handle |= TC_H_MIN(cl);
352	tcm->tcm_info = q->queues[cl - 1]->handle;
353	return 0;
354}
355
356static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
357				 struct gnet_dump *d)
358{
359	struct multiq_sched_data *q = qdisc_priv(sch);
360	struct Qdisc *cl_q;
361
362	cl_q = q->queues[cl - 1];
363	cl_q->qstats.qlen = cl_q->q.qlen;
364	if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
365	    gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
366		return -1;
367
368	return 0;
369}
370
371static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
372{
373	struct multiq_sched_data *q = qdisc_priv(sch);
374	int band;
375
376	if (arg->stop)
377		return;
378
379	for (band = 0; band < q->bands; band++) {
380		if (arg->count < arg->skip) {
381			arg->count++;
382			continue;
383		}
384		if (arg->fn(sch, band + 1, arg) < 0) {
385			arg->stop = 1;
386			break;
387		}
388		arg->count++;
389	}
390}
391
392static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
393{
394	struct multiq_sched_data *q = qdisc_priv(sch);
395
396	if (cl)
397		return NULL;
398	return &q->filter_list;
399}
400
401static const struct Qdisc_class_ops multiq_class_ops = {
402	.graft		=	multiq_graft,
403	.leaf		=	multiq_leaf,
404	.get		=	multiq_get,
405	.put		=	multiq_put,
406	.walk		=	multiq_walk,
407	.tcf_chain	=	multiq_find_tcf,
408	.bind_tcf	=	multiq_bind,
409	.unbind_tcf	=	multiq_put,
410	.dump		=	multiq_dump_class,
411	.dump_stats	=	multiq_dump_class_stats,
412};
413
414static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
415	.next		=	NULL,
416	.cl_ops		=	&multiq_class_ops,
417	.id		=	"multiq",
418	.priv_size	=	sizeof(struct multiq_sched_data),
419	.enqueue	=	multiq_enqueue,
420	.dequeue	=	multiq_dequeue,
421	.peek		=	multiq_peek,
422	.drop		=	multiq_drop,
423	.init		=	multiq_init,
424	.reset		=	multiq_reset,
425	.destroy	=	multiq_destroy,
426	.change		=	multiq_tune,
427	.dump		=	multiq_dump,
428	.owner		=	THIS_MODULE,
429};
430
431static int __init multiq_module_init(void)
432{
433	return register_qdisc(&multiq_qdisc_ops);
434}
435
436static void __exit multiq_module_exit(void)
437{
438	unregister_qdisc(&multiq_qdisc_ops);
439}
440
441module_init(multiq_module_init)
442module_exit(multiq_module_exit)
443
444MODULE_LICENSE("GPL");
445