pkt_sched: Remove qdisc->ops->requeue() etc.
[linux-2.6.git] / net / sched / sch_multiq.c
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
30 struct 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
39 static struct Qdisc *
40 multiq_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
66 static int
67 multiq_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
95 static 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
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 -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
249 static 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
275 static 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
288 nla_put_failure:
289         nlmsg_trim(skb, b);
290         return -1;
291 }
292
293 static 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
315 static struct Qdisc *
316 multiq_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
327 static 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
337 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
338                                  u32 classid)
339 {
340         return multiq_get(sch, classid);
341 }
342
343
344 static void multiq_put(struct Qdisc *q, unsigned long cl)
345 {
346         return;
347 }
348
349 static 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
360 static 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
369 static 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
382 static 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
396 static 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
417 static 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
426 static 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
441 static 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
458 static int __init multiq_module_init(void)
459 {
460         return register_qdisc(&multiq_qdisc_ops);
461 }
462
463 static void __exit multiq_module_exit(void)
464 {
465         unregister_qdisc(&multiq_qdisc_ops);
466 }
467
468 module_init(multiq_module_init)
469 module_exit(multiq_module_exit)
470
471 MODULE_LICENSE("GPL");