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->bstats.bytes += qdisc_pkt_len(skb);
87		sch->bstats.packets++;
88		sch->q.qlen++;
89		return NET_XMIT_SUCCESS;
90	}
91	if (net_xmit_drop_count(ret))
92		sch->qstats.drops++;
93	return ret;
94}
95
96static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
97{
98	struct multiq_sched_data *q = qdisc_priv(sch);
99	struct Qdisc *qdisc;
100	struct sk_buff *skb;
101	int band;
102
103	for (band = 0; band < q->bands; band++) {
104		/* cycle through bands to ensure fairness */
105		q->curband++;
106		if (q->curband >= q->bands)
107			q->curband = 0;
108
109		/* Check that target subqueue is available before
110		 * pulling an skb to avoid head-of-line blocking.
111		 */
112		if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
113			qdisc = q->queues[q->curband];
114			skb = qdisc->dequeue(qdisc);
115			if (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_subqueue_stopped(qdisc_dev(sch), curband)) {
143			qdisc = q->queues[curband];
144			skb = qdisc->ops->peek(qdisc);
145			if (skb)
146				return skb;
147		}
148	}
149	return NULL;
150
151}
152
153static unsigned int multiq_drop(struct Qdisc *sch)
154{
155	struct multiq_sched_data *q = qdisc_priv(sch);
156	int band;
157	unsigned int len;
158	struct Qdisc *qdisc;
159
160	for (band = q->bands-1; band >= 0; band--) {
161		qdisc = q->queues[band];
162		if (qdisc->ops->drop) {
163			len = qdisc->ops->drop(qdisc);
164			if (len != 0) {
165				sch->q.qlen--;
166				return len;
167			}
168		}
169	}
170	return 0;
171}
172
173
174static void
175multiq_reset(struct Qdisc *sch)
176{
177	u16 band;
178	struct multiq_sched_data *q = qdisc_priv(sch);
179
180	for (band = 0; band < q->bands; band++)
181		qdisc_reset(q->queues[band]);
182	sch->q.qlen = 0;
183	q->curband = 0;
184}
185
186static void
187multiq_destroy(struct Qdisc *sch)
188{
189	int band;
190	struct multiq_sched_data *q = qdisc_priv(sch);
191
192	tcf_destroy_chain(&q->filter_list);
193	for (band = 0; band < q->bands; band++)
194		qdisc_destroy(q->queues[band]);
195
196	kfree(q->queues);
197}
198
199static int multiq_tune(struct Qdisc *sch, struct nlattr *opt)
200{
201	struct multiq_sched_data *q = qdisc_priv(sch);
202	struct tc_multiq_qopt *qopt;
203	int i;
204
205	if (!netif_is_multiqueue(qdisc_dev(sch)))
206		return -EOPNOTSUPP;
207	if (nla_len(opt) < sizeof(*qopt))
208		return -EINVAL;
209
210	qopt = nla_data(opt);
211
212	qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
213
214	sch_tree_lock(sch);
215	q->bands = qopt->bands;
216	for (i = q->bands; i < q->max_bands; i++) {
217		if (q->queues[i] != &noop_qdisc) {
218			struct Qdisc *child = q->queues[i];
219			q->queues[i] = &noop_qdisc;
220			qdisc_tree_decrease_qlen(child, child->q.qlen);
221			qdisc_destroy(child);
222		}
223	}
224
225	sch_tree_unlock(sch);
226
227	for (i = 0; i < q->bands; i++) {
228		if (q->queues[i] == &noop_qdisc) {
229			struct Qdisc *child, *old;
230			child = qdisc_create_dflt(qdisc_dev(sch),
231						  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	NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
288
289	return skb->len;
290
291nla_put_failure:
292	nlmsg_trim(skb, b);
293	return -1;
294}
295
296static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
297		      struct Qdisc **old)
298{
299	struct multiq_sched_data *q = qdisc_priv(sch);
300	unsigned long band = arg - 1;
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	return q->queues[band];
322}
323
324static unsigned long multiq_get(struct Qdisc *sch, u32 classid)
325{
326	struct multiq_sched_data *q = qdisc_priv(sch);
327	unsigned long band = TC_H_MIN(classid);
328
329	if (band - 1 >= q->bands)
330		return 0;
331	return band;
332}
333
334static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
335				 u32 classid)
336{
337	return multiq_get(sch, classid);
338}
339
340
341static void multiq_put(struct Qdisc *q, unsigned long cl)
342{
343}
344
345static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
346			     struct sk_buff *skb, struct tcmsg *tcm)
347{
348	struct multiq_sched_data *q = qdisc_priv(sch);
349
350	tcm->tcm_handle |= TC_H_MIN(cl);
351	tcm->tcm_info = q->queues[cl-1]->handle;
352	return 0;
353}
354
355static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
356				 struct gnet_dump *d)
357{
358	struct multiq_sched_data *q = qdisc_priv(sch);
359	struct Qdisc *cl_q;
360
361	cl_q = q->queues[cl - 1];
362	cl_q->qstats.qlen = cl_q->q.qlen;
363	if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
364	    gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
365		return -1;
366
367	return 0;
368}
369
370static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
371{
372	struct multiq_sched_data *q = qdisc_priv(sch);
373	int band;
374
375	if (arg->stop)
376		return;
377
378	for (band = 0; band < q->bands; band++) {
379		if (arg->count < arg->skip) {
380			arg->count++;
381			continue;
382		}
383		if (arg->fn(sch, band+1, arg) < 0) {
384			arg->stop = 1;
385			break;
386		}
387		arg->count++;
388	}
389}
390
391static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl)
392{
393	struct multiq_sched_data *q = qdisc_priv(sch);
394
395	if (cl)
396		return NULL;
397	return &q->filter_list;
398}
399
400static const struct Qdisc_class_ops multiq_class_ops = {
401	.graft		=	multiq_graft,
402	.leaf		=	multiq_leaf,
403	.get		=	multiq_get,
404	.put		=	multiq_put,
405	.walk		=	multiq_walk,
406	.tcf_chain	=	multiq_find_tcf,
407	.bind_tcf	=	multiq_bind,
408	.unbind_tcf	=	multiq_put,
409	.dump		=	multiq_dump_class,
410	.dump_stats	=	multiq_dump_class_stats,
411};
412
413static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
414	.next		=	NULL,
415	.cl_ops		=	&multiq_class_ops,
416	.id		=	"multiq",
417	.priv_size	=	sizeof(struct multiq_sched_data),
418	.enqueue	=	multiq_enqueue,
419	.dequeue	=	multiq_dequeue,
420	.peek		=	multiq_peek,
421	.drop		=	multiq_drop,
422	.init		=	multiq_init,
423	.reset		=	multiq_reset,
424	.destroy	=	multiq_destroy,
425	.change		=	multiq_tune,
426	.dump		=	multiq_dump,
427	.owner		=	THIS_MODULE,
428};
429
430static int __init multiq_module_init(void)
431{
432	return register_qdisc(&multiq_qdisc_ops);
433}
434
435static void __exit multiq_module_exit(void)
436{
437	unregister_qdisc(&multiq_qdisc_ops);
438}
439
440module_init(multiq_module_init)
441module_exit(multiq_module_exit)
442
443MODULE_LICENSE("GPL");
444