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
19struct 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
29static struct Qdisc *
30multiq_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, NULL, tp: fl, res: &res, compat_mode: 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
59static int
60multiq_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, qerr: &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, sch: 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
87static 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 dev_queue: netdev_get_tx_queue(dev: qdisc_dev(qdisc: sch), index: 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
118static 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 dev_queue: netdev_get_tx_queue(dev: qdisc_dev(qdisc: sch), index: 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
147static void
148multiq_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(qdisc: q->queues[band]);
155 q->curband = 0;
156}
157
158static void
159multiq_destroy(struct Qdisc *sch)
160{
161 int band;
162 struct multiq_sched_data *q = qdisc_priv(sch);
163
164 tcf_block_put(block: q->block);
165 for (band = 0; band < q->bands; band++)
166 qdisc_put(qdisc: q->queues[band]);
167
168 kfree(objp: q->queues);
169}
170
171static int multiq_tune(struct Qdisc *sch, struct nlattr *opt,
172 struct netlink_ext_ack *extack)
173{
174 struct multiq_sched_data *q = qdisc_priv(sch);
175 struct tc_multiq_qopt *qopt;
176 struct Qdisc **removed;
177 int i, n_removed = 0;
178
179 if (!netif_is_multiqueue(dev: qdisc_dev(qdisc: sch)))
180 return -EOPNOTSUPP;
181 if (nla_len(nla: opt) < sizeof(*qopt))
182 return -EINVAL;
183
184 qopt = nla_data(nla: opt);
185
186 qopt->bands = qdisc_dev(qdisc: sch)->real_num_tx_queues;
187
188 removed = kmalloc(size: sizeof(*removed) * (q->max_bands - q->bands),
189 GFP_KERNEL);
190 if (!removed)
191 return -ENOMEM;
192
193 sch_tree_lock(q: sch);
194 q->bands = qopt->bands;
195 for (i = q->bands; i < q->max_bands; i++) {
196 if (q->queues[i] != &noop_qdisc) {
197 struct Qdisc *child = q->queues[i];
198
199 q->queues[i] = &noop_qdisc;
200 qdisc_purge_queue(sch: child);
201 removed[n_removed++] = child;
202 }
203 }
204
205 sch_tree_unlock(q: sch);
206
207 for (i = 0; i < n_removed; i++)
208 qdisc_put(qdisc: removed[i]);
209 kfree(objp: removed);
210
211 for (i = 0; i < q->bands; i++) {
212 if (q->queues[i] == &noop_qdisc) {
213 struct Qdisc *child, *old;
214 child = qdisc_create_dflt(dev_queue: sch->dev_queue,
215 ops: &pfifo_qdisc_ops,
216 TC_H_MAKE(sch->handle,
217 i + 1), extack);
218 if (child) {
219 sch_tree_lock(q: sch);
220 old = q->queues[i];
221 q->queues[i] = child;
222 if (child != &noop_qdisc)
223 qdisc_hash_add(q: child, invisible: true);
224
225 if (old != &noop_qdisc)
226 qdisc_purge_queue(sch: old);
227 sch_tree_unlock(q: sch);
228 qdisc_put(qdisc: old);
229 }
230 }
231 }
232 return 0;
233}
234
235static int multiq_init(struct Qdisc *sch, struct nlattr *opt,
236 struct netlink_ext_ack *extack)
237{
238 struct multiq_sched_data *q = qdisc_priv(sch);
239 int i, err;
240
241 q->queues = NULL;
242
243 if (!opt)
244 return -EINVAL;
245
246 err = tcf_block_get(p_block: &q->block, p_filter_chain: &q->filter_list, q: sch, extack);
247 if (err)
248 return err;
249
250 q->max_bands = qdisc_dev(qdisc: sch)->num_tx_queues;
251
252 q->queues = kcalloc(n: q->max_bands, size: sizeof(struct Qdisc *), GFP_KERNEL);
253 if (!q->queues)
254 return -ENOBUFS;
255 for (i = 0; i < q->max_bands; i++)
256 q->queues[i] = &noop_qdisc;
257
258 return multiq_tune(sch, opt, extack);
259}
260
261static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb)
262{
263 struct multiq_sched_data *q = qdisc_priv(sch);
264 unsigned char *b = skb_tail_pointer(skb);
265 struct tc_multiq_qopt opt;
266
267 opt.bands = q->bands;
268 opt.max_bands = q->max_bands;
269
270 if (nla_put(skb, attrtype: TCA_OPTIONS, attrlen: sizeof(opt), data: &opt))
271 goto nla_put_failure;
272
273 return skb->len;
274
275nla_put_failure:
276 nlmsg_trim(skb, mark: b);
277 return -1;
278}
279
280static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
281 struct Qdisc **old, struct netlink_ext_ack *extack)
282{
283 struct multiq_sched_data *q = qdisc_priv(sch);
284 unsigned long band = arg - 1;
285
286 if (new == NULL)
287 new = &noop_qdisc;
288
289 *old = qdisc_replace(sch, new, pold: &q->queues[band]);
290 return 0;
291}
292
293static struct Qdisc *
294multiq_leaf(struct Qdisc *sch, unsigned long arg)
295{
296 struct multiq_sched_data *q = qdisc_priv(sch);
297 unsigned long band = arg - 1;
298
299 return q->queues[band];
300}
301
302static unsigned long multiq_find(struct Qdisc *sch, u32 classid)
303{
304 struct multiq_sched_data *q = qdisc_priv(sch);
305 unsigned long band = TC_H_MIN(classid);
306
307 if (band - 1 >= q->bands)
308 return 0;
309 return band;
310}
311
312static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent,
313 u32 classid)
314{
315 return multiq_find(sch, classid);
316}
317
318
319static void multiq_unbind(struct Qdisc *q, unsigned long cl)
320{
321}
322
323static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
324 struct sk_buff *skb, struct tcmsg *tcm)
325{
326 struct multiq_sched_data *q = qdisc_priv(sch);
327
328 tcm->tcm_handle |= TC_H_MIN(cl);
329 tcm->tcm_info = q->queues[cl - 1]->handle;
330 return 0;
331}
332
333static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
334 struct gnet_dump *d)
335{
336 struct multiq_sched_data *q = qdisc_priv(sch);
337 struct Qdisc *cl_q;
338
339 cl_q = q->queues[cl - 1];
340 if (gnet_stats_copy_basic(d, cpu: cl_q->cpu_bstats, b: &cl_q->bstats, running: true) < 0 ||
341 qdisc_qstats_copy(d, sch: cl_q) < 0)
342 return -1;
343
344 return 0;
345}
346
347static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
348{
349 struct multiq_sched_data *q = qdisc_priv(sch);
350 int band;
351
352 if (arg->stop)
353 return;
354
355 for (band = 0; band < q->bands; band++) {
356 if (!tc_qdisc_stats_dump(sch, cl: band + 1, arg))
357 break;
358 }
359}
360
361static struct tcf_block *multiq_tcf_block(struct Qdisc *sch, unsigned long cl,
362 struct netlink_ext_ack *extack)
363{
364 struct multiq_sched_data *q = qdisc_priv(sch);
365
366 if (cl)
367 return NULL;
368 return q->block;
369}
370
371static const struct Qdisc_class_ops multiq_class_ops = {
372 .graft = multiq_graft,
373 .leaf = multiq_leaf,
374 .find = multiq_find,
375 .walk = multiq_walk,
376 .tcf_block = multiq_tcf_block,
377 .bind_tcf = multiq_bind,
378 .unbind_tcf = multiq_unbind,
379 .dump = multiq_dump_class,
380 .dump_stats = multiq_dump_class_stats,
381};
382
383static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
384 .next = NULL,
385 .cl_ops = &multiq_class_ops,
386 .id = "multiq",
387 .priv_size = sizeof(struct multiq_sched_data),
388 .enqueue = multiq_enqueue,
389 .dequeue = multiq_dequeue,
390 .peek = multiq_peek,
391 .init = multiq_init,
392 .reset = multiq_reset,
393 .destroy = multiq_destroy,
394 .change = multiq_tune,
395 .dump = multiq_dump,
396 .owner = THIS_MODULE,
397};
398
399static int __init multiq_module_init(void)
400{
401 return register_qdisc(qops: &multiq_qdisc_ops);
402}
403
404static void __exit multiq_module_exit(void)
405{
406 unregister_qdisc(qops: &multiq_qdisc_ops);
407}
408
409module_init(multiq_module_init)
410module_exit(multiq_module_exit)
411
412MODULE_LICENSE("GPL");
413

source code of linux/net/sched/sch_multiq.c