xref: /kernel/linux/linux-5.10/net/sched/sch_multiq.c (revision 8c2ecf20) 
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, 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
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, &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
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		    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
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		    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
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(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(q->block);
165	for (band = 0; band < q->bands; band++)
166		qdisc_put(q->queues[band]);
167
168	kfree(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(qdisc_dev(sch)))
180		return -EOPNOTSUPP;
181	if (nla_len(opt) < sizeof(*qopt))
182		return -EINVAL;
183
184	qopt = nla_data(opt);
185
186	qopt->bands = qdisc_dev(sch)->real_num_tx_queues;
187
188	removed = kmalloc(sizeof(*removed) * (q->max_bands - q->bands),
189			  GFP_KERNEL);
190	if (!removed)
191		return -ENOMEM;
192
193	sch_tree_lock(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(child);
201			removed[n_removed++] = child;
202		}
203	}
204
205	sch_tree_unlock(sch);
206
207	for (i = 0; i < n_removed; i++)
208		qdisc_put(removed[i]);
209	kfree(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(sch->dev_queue,
215						  &pfifo_qdisc_ops,
216						  TC_H_MAKE(sch->handle,
217							    i + 1), extack);
218			if (child) {
219				sch_tree_lock(sch);
220				old = q->queues[i];
221				q->queues[i] = child;
222				if (child != &noop_qdisc)
223					qdisc_hash_add(child, true);
224
225				if (old != &noop_qdisc)
226					qdisc_purge_queue(old);
227				sch_tree_unlock(sch);
228				qdisc_put(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(&q->block, &q->filter_list, sch, extack);
247	if (err)
248		return err;
249
250	q->max_bands = qdisc_dev(sch)->num_tx_queues;
251
252	q->queues = kcalloc(q->max_bands, 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, TCA_OPTIONS, sizeof(opt), &opt))
271		goto nla_put_failure;
272
273	return skb->len;
274
275nla_put_failure:
276	nlmsg_trim(skb, 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, &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(qdisc_root_sleeping_running(sch),
341				  d, cl_q->cpu_bstats, &cl_q->bstats) < 0 ||
342	    qdisc_qstats_copy(d, cl_q) < 0)
343		return -1;
344
345	return 0;
346}
347
348static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
349{
350	struct multiq_sched_data *q = qdisc_priv(sch);
351	int band;
352
353	if (arg->stop)
354		return;
355
356	for (band = 0; band < q->bands; band++) {
357		if (arg->count < arg->skip) {
358			arg->count++;
359			continue;
360		}
361		if (arg->fn(sch, band + 1, arg) < 0) {
362			arg->stop = 1;
363			break;
364		}
365		arg->count++;
366	}
367}
368
369static struct tcf_block *multiq_tcf_block(struct Qdisc *sch, unsigned long cl,
370					  struct netlink_ext_ack *extack)
371{
372	struct multiq_sched_data *q = qdisc_priv(sch);
373
374	if (cl)
375		return NULL;
376	return q->block;
377}
378
379static const struct Qdisc_class_ops multiq_class_ops = {
380	.graft		=	multiq_graft,
381	.leaf		=	multiq_leaf,
382	.find		=	multiq_find,
383	.walk		=	multiq_walk,
384	.tcf_block	=	multiq_tcf_block,
385	.bind_tcf	=	multiq_bind,
386	.unbind_tcf	=	multiq_unbind,
387	.dump		=	multiq_dump_class,
388	.dump_stats	=	multiq_dump_class_stats,
389};
390
391static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
392	.next		=	NULL,
393	.cl_ops		=	&multiq_class_ops,
394	.id		=	"multiq",
395	.priv_size	=	sizeof(struct multiq_sched_data),
396	.enqueue	=	multiq_enqueue,
397	.dequeue	=	multiq_dequeue,
398	.peek		=	multiq_peek,
399	.init		=	multiq_init,
400	.reset		=	multiq_reset,
401	.destroy	=	multiq_destroy,
402	.change		=	multiq_tune,
403	.dump		=	multiq_dump,
404	.owner		=	THIS_MODULE,
405};
406
407static int __init multiq_module_init(void)
408{
409	return register_qdisc(&multiq_qdisc_ops);
410}
411
412static void __exit multiq_module_exit(void)
413{
414	unregister_qdisc(&multiq_qdisc_ops);
415}
416
417module_init(multiq_module_init)
418module_exit(multiq_module_exit)
419
420MODULE_LICENSE("GPL");
421