1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2008, Intel Corporation.
4 *
5 * Author: Alexander Duyck <alexander.h.duyck@intel.com>
6 */
7
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/errno.h>
14 #include <linux/skbuff.h>
15 #include <net/netlink.h>
16 #include <net/pkt_sched.h>
17 #include <net/pkt_cls.h>
18
19 struct multiq_sched_data {
20 u16 bands;
21 u16 max_bands;
22 u16 curband;
23 struct tcf_proto __rcu *filter_list;
24 struct tcf_block *block;
25 struct Qdisc **queues;
26 };
27
28
29 static struct Qdisc *
multiq_classify(struct sk_buff * skb,struct Qdisc * sch,int * qerr)30 multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
31 {
32 struct multiq_sched_data *q = qdisc_priv(sch);
33 u32 band;
34 struct tcf_result res;
35 struct tcf_proto *fl = rcu_dereference_bh(q->filter_list);
36 int err;
37
38 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
39 err = tcf_classify(skb, fl, &res, false);
40 #ifdef CONFIG_NET_CLS_ACT
41 switch (err) {
42 case TC_ACT_STOLEN:
43 case TC_ACT_QUEUED:
44 case TC_ACT_TRAP:
45 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
46 fallthrough;
47 case TC_ACT_SHOT:
48 return NULL;
49 }
50 #endif
51 band = skb_get_queue_mapping(skb);
52
53 if (band >= q->bands)
54 return q->queues[0];
55
56 return q->queues[band];
57 }
58
59 static int
multiq_enqueue(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)60 multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
61 struct sk_buff **to_free)
62 {
63 struct Qdisc *qdisc;
64 int ret;
65
66 qdisc = multiq_classify(skb, sch, &ret);
67 #ifdef CONFIG_NET_CLS_ACT
68 if (qdisc == NULL) {
69
70 if (ret & __NET_XMIT_BYPASS)
71 qdisc_qstats_drop(sch);
72 __qdisc_drop(skb, to_free);
73 return ret;
74 }
75 #endif
76
77 ret = qdisc_enqueue(skb, qdisc, to_free);
78 if (ret == NET_XMIT_SUCCESS) {
79 sch->q.qlen++;
80 return NET_XMIT_SUCCESS;
81 }
82 if (net_xmit_drop_count(ret))
83 qdisc_qstats_drop(sch);
84 return ret;
85 }
86
multiq_dequeue(struct Qdisc * sch)87 static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
88 {
89 struct multiq_sched_data *q = qdisc_priv(sch);
90 struct Qdisc *qdisc;
91 struct sk_buff *skb;
92 int band;
93
94 for (band = 0; band < q->bands; band++) {
95 /* cycle through bands to ensure fairness */
96 q->curband++;
97 if (q->curband >= q->bands)
98 q->curband = 0;
99
100 /* Check that target subqueue is available before
101 * pulling an skb to avoid head-of-line blocking.
102 */
103 if (!netif_xmit_stopped(
104 netdev_get_tx_queue(qdisc_dev(sch), q->curband))) {
105 qdisc = q->queues[q->curband];
106 skb = qdisc->dequeue(qdisc);
107 if (skb) {
108 qdisc_bstats_update(sch, skb);
109 sch->q.qlen--;
110 return skb;
111 }
112 }
113 }
114 return NULL;
115
116 }
117
multiq_peek(struct Qdisc * sch)118 static struct sk_buff *multiq_peek(struct Qdisc *sch)
119 {
120 struct multiq_sched_data *q = qdisc_priv(sch);
121 unsigned int curband = q->curband;
122 struct Qdisc *qdisc;
123 struct sk_buff *skb;
124 int band;
125
126 for (band = 0; band < q->bands; band++) {
127 /* cycle through bands to ensure fairness */
128 curband++;
129 if (curband >= q->bands)
130 curband = 0;
131
132 /* Check that target subqueue is available before
133 * pulling an skb to avoid head-of-line blocking.
134 */
135 if (!netif_xmit_stopped(
136 netdev_get_tx_queue(qdisc_dev(sch), curband))) {
137 qdisc = q->queues[curband];
138 skb = qdisc->ops->peek(qdisc);
139 if (skb)
140 return skb;
141 }
142 }
143 return NULL;
144
145 }
146
147 static void
multiq_reset(struct Qdisc * sch)148 multiq_reset(struct Qdisc *sch)
149 {
150 u16 band;
151 struct multiq_sched_data *q = qdisc_priv(sch);
152
153 for (band = 0; band < q->bands; band++)
154 qdisc_reset(q->queues[band]);
155 sch->q.qlen = 0;
156 q->curband = 0;
157 }
158
159 static void
multiq_destroy(struct Qdisc * sch)160 multiq_destroy(struct Qdisc *sch)
161 {
162 int band;
163 struct multiq_sched_data *q = qdisc_priv(sch);
164
165 tcf_block_put(q->block);
166 for (band = 0; band < q->bands; band++)
167 qdisc_put(q->queues[band]);
168
169 kfree(q->queues);
170 }
171
multiq_tune(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)172 static int multiq_tune(struct Qdisc *sch, struct nlattr *opt,
173 struct netlink_ext_ack *extack)
174 {
175 struct multiq_sched_data *q = qdisc_priv(sch);
176 struct tc_multiq_qopt *qopt;
177 struct Qdisc **removed;
178 int i, n_removed = 0;
179
180 if (!netif_is_multiqueue(qdisc_dev(sch)))
181 return -EOPNOTSUPP;
182 if (nla_len(opt) < sizeof(*qopt))
183 return -EINVAL;
184
185 qopt = nla_data(opt);
186
187 qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
188
189 removed = kmalloc(sizeof(*removed) * (q->max_bands - q->bands),
190 GFP_KERNEL);
191 if (!removed)
192 return -ENOMEM;
193
194 sch_tree_lock(sch);
195 q->bands = qopt->bands;
196 for (i = q->bands; i < q->max_bands; i++) {
197 if (q->queues[i] != &noop_qdisc) {
198 struct Qdisc *child = q->queues[i];
199
200 q->queues[i] = &noop_qdisc;
201 qdisc_purge_queue(child);
202 removed[n_removed++] = child;
203 }
204 }
205
206 sch_tree_unlock(sch);
207
208 for (i = 0; i < n_removed; i++)
209 qdisc_put(removed[i]);
210 kfree(removed);
211
212 for (i = 0; i < q->bands; i++) {
213 if (q->queues[i] == &noop_qdisc) {
214 struct Qdisc *child, *old;
215 child = qdisc_create_dflt(sch->dev_queue,
216 &pfifo_qdisc_ops,
217 TC_H_MAKE(sch->handle,
218 i + 1), extack);
219 if (child) {
220 sch_tree_lock(sch);
221 old = q->queues[i];
222 q->queues[i] = child;
223 if (child != &noop_qdisc)
224 qdisc_hash_add(child, true);
225
226 if (old != &noop_qdisc)
227 qdisc_purge_queue(old);
228 sch_tree_unlock(sch);
229 qdisc_put(old);
230 }
231 }
232 }
233 return 0;
234 }
235
multiq_init(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)236 static int multiq_init(struct Qdisc *sch, struct nlattr *opt,
237 struct netlink_ext_ack *extack)
238 {
239 struct multiq_sched_data *q = qdisc_priv(sch);
240 int i, err;
241
242 q->queues = NULL;
243
244 if (!opt)
245 return -EINVAL;
246
247 err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
248 if (err)
249 return err;
250
251 q->max_bands = qdisc_dev(sch)->num_tx_queues;
252
253 q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL);
254 if (!q->queues)
255 return -ENOBUFS;
256 for (i = 0; i < q->max_bands; i++)
257 q->queues[i] = &noop_qdisc;
258
259 return multiq_tune(sch, opt, extack);
260 }
261
multiq_dump(struct Qdisc * sch,struct sk_buff * skb)262 static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
263 {
264 struct multiq_sched_data *q = qdisc_priv(sch);
265 unsigned char *b = skb_tail_pointer(skb);
266 struct tc_multiq_qopt opt;
267
268 opt.bands = q->bands;
269 opt.max_bands = q->max_bands;
270
271 if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
272 goto nla_put_failure;
273
274 return skb->len;
275
276 nla_put_failure:
277 nlmsg_trim(skb, b);
278 return -1;
279 }
280
multiq_graft(struct Qdisc * sch,unsigned long arg,struct Qdisc * new,struct Qdisc ** old,struct netlink_ext_ack * extack)281 static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
282 struct Qdisc **old, struct netlink_ext_ack *extack)
283 {
284 struct multiq_sched_data *q = qdisc_priv(sch);
285 unsigned long band = arg - 1;
286
287 if (new == NULL)
288 new = &noop_qdisc;
289
290 *old = qdisc_replace(sch, new, &q->queues[band]);
291 return 0;
292 }
293
294 static struct Qdisc *
multiq_leaf(struct Qdisc * sch,unsigned long arg)295 multiq_leaf(struct Qdisc *sch, unsigned long arg)
296 {
297 struct multiq_sched_data *q = qdisc_priv(sch);
298 unsigned long band = arg - 1;
299
300 return q->queues[band];
301 }
302
multiq_find(struct Qdisc * sch,u32 classid)303 static unsigned long multiq_find(struct Qdisc *sch, u32 classid)
304 {
305 struct multiq_sched_data *q = qdisc_priv(sch);
306 unsigned long band = TC_H_MIN(classid);
307
308 if (band - 1 >= q->bands)
309 return 0;
310 return band;
311 }
312
multiq_bind(struct Qdisc * sch,unsigned long parent,u32 classid)313 static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
314 u32 classid)
315 {
316 return multiq_find(sch, classid);
317 }
318
319
multiq_unbind(struct Qdisc * q,unsigned long cl)320 static void multiq_unbind(struct Qdisc *q, unsigned long cl)
321 {
322 }
323
multiq_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)324 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
325 struct sk_buff *skb, struct tcmsg *tcm)
326 {
327 struct multiq_sched_data *q = qdisc_priv(sch);
328
329 tcm->tcm_handle |= TC_H_MIN(cl);
330 tcm->tcm_info = q->queues[cl - 1]->handle;
331 return 0;
332 }
333
multiq_dump_class_stats(struct Qdisc * sch,unsigned long cl,struct gnet_dump * d)334 static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
335 struct gnet_dump *d)
336 {
337 struct multiq_sched_data *q = qdisc_priv(sch);
338 struct Qdisc *cl_q;
339
340 cl_q = q->queues[cl - 1];
341 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
342 d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
343 qdisc_qstats_copy(d, cl_q) < 0)
344 return -1;
345
346 return 0;
347 }
348
multiq_walk(struct Qdisc * sch,struct qdisc_walker * arg)349 static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
350 {
351 struct multiq_sched_data *q = qdisc_priv(sch);
352 int band;
353
354 if (arg->stop)
355 return;
356
357 for (band = 0; band < q->bands; band++) {
358 if (arg->count < arg->skip) {
359 arg->count++;
360 continue;
361 }
362 if (arg->fn(sch, band + 1, arg) < 0) {
363 arg->stop = 1;
364 break;
365 }
366 arg->count++;
367 }
368 }
369
multiq_tcf_block(struct Qdisc * sch,unsigned long cl,struct netlink_ext_ack * extack)370 static struct tcf_block *multiq_tcf_block(struct Qdisc *sch, unsigned long cl,
371 struct netlink_ext_ack *extack)
372 {
373 struct multiq_sched_data *q = qdisc_priv(sch);
374
375 if (cl)
376 return NULL;
377 return q->block;
378 }
379
380 static const struct Qdisc_class_ops multiq_class_ops = {
381 .graft = multiq_graft,
382 .leaf = multiq_leaf,
383 .find = multiq_find,
384 .walk = multiq_walk,
385 .tcf_block = multiq_tcf_block,
386 .bind_tcf = multiq_bind,
387 .unbind_tcf = multiq_unbind,
388 .dump = multiq_dump_class,
389 .dump_stats = multiq_dump_class_stats,
390 };
391
392 static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
393 .next = NULL,
394 .cl_ops = &multiq_class_ops,
395 .id = "multiq",
396 .priv_size = sizeof(struct multiq_sched_data),
397 .enqueue = multiq_enqueue,
398 .dequeue = multiq_dequeue,
399 .peek = multiq_peek,
400 .init = multiq_init,
401 .reset = multiq_reset,
402 .destroy = multiq_destroy,
403 .change = multiq_tune,
404 .dump = multiq_dump,
405 .owner = THIS_MODULE,
406 };
407
multiq_module_init(void)408 static int __init multiq_module_init(void)
409 {
410 return register_qdisc(&multiq_qdisc_ops);
411 }
412
multiq_module_exit(void)413 static void __exit multiq_module_exit(void)
414 {
415 unregister_qdisc(&multiq_qdisc_ops);
416 }
417
418 module_init(multiq_module_init)
419 module_exit(multiq_module_exit)
420
421 MODULE_LICENSE("GPL");
422