1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/sched/sch_mq.c Classful multiqueue dummy scheduler
4 *
5 * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
6 */
7
8 #include <linux/types.h>
9 #include <linux/slab.h>
10 #include <linux/kernel.h>
11 #include <linux/export.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_cls.h>
17 #include <net/pkt_sched.h>
18 #include <net/sch_generic.h>
19
20 struct mq_sched {
21 struct Qdisc **qdiscs;
22 };
23
mq_offload(struct Qdisc * sch,enum tc_mq_command cmd)24 static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd)
25 {
26 struct net_device *dev = qdisc_dev(sch);
27 struct tc_mq_qopt_offload opt = {
28 .command = cmd,
29 .handle = sch->handle,
30 };
31
32 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
33 return -EOPNOTSUPP;
34
35 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_MQ, &opt);
36 }
37
mq_offload_stats(struct Qdisc * sch)38 static int mq_offload_stats(struct Qdisc *sch)
39 {
40 struct tc_mq_qopt_offload opt = {
41 .command = TC_MQ_STATS,
42 .handle = sch->handle,
43 .stats = {
44 .bstats = &sch->bstats,
45 .qstats = &sch->qstats,
46 },
47 };
48
49 return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_MQ, &opt);
50 }
51
mq_destroy(struct Qdisc * sch)52 static void mq_destroy(struct Qdisc *sch)
53 {
54 struct net_device *dev = qdisc_dev(sch);
55 struct mq_sched *priv = qdisc_priv(sch);
56 unsigned int ntx;
57
58 mq_offload(sch, TC_MQ_DESTROY);
59
60 if (!priv->qdiscs)
61 return;
62 for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
63 qdisc_put(priv->qdiscs[ntx]);
64 kfree(priv->qdiscs);
65 }
66
mq_init(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)67 static int mq_init(struct Qdisc *sch, struct nlattr *opt,
68 struct netlink_ext_ack *extack)
69 {
70 struct net_device *dev = qdisc_dev(sch);
71 struct mq_sched *priv = qdisc_priv(sch);
72 struct netdev_queue *dev_queue;
73 struct Qdisc *qdisc;
74 unsigned int ntx;
75
76 if (sch->parent != TC_H_ROOT)
77 return -EOPNOTSUPP;
78
79 if (!netif_is_multiqueue(dev))
80 return -EOPNOTSUPP;
81
82 /* pre-allocate qdiscs, attachment can't fail */
83 priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
84 GFP_KERNEL);
85 if (!priv->qdiscs)
86 return -ENOMEM;
87
88 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
89 dev_queue = netdev_get_tx_queue(dev, ntx);
90 qdisc = qdisc_create_dflt(dev_queue, get_default_qdisc_ops(dev, ntx),
91 TC_H_MAKE(TC_H_MAJ(sch->handle),
92 TC_H_MIN(ntx + 1)),
93 extack);
94 if (!qdisc)
95 return -ENOMEM;
96 priv->qdiscs[ntx] = qdisc;
97 qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
98 }
99
100 sch->flags |= TCQ_F_MQROOT;
101
102 mq_offload(sch, TC_MQ_CREATE);
103 return 0;
104 }
105
mq_attach(struct Qdisc * sch)106 static void mq_attach(struct Qdisc *sch)
107 {
108 struct net_device *dev = qdisc_dev(sch);
109 struct mq_sched *priv = qdisc_priv(sch);
110 struct Qdisc *qdisc, *old;
111 unsigned int ntx;
112
113 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
114 qdisc = priv->qdiscs[ntx];
115 old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
116 if (old)
117 qdisc_put(old);
118 #ifdef CONFIG_NET_SCHED
119 if (ntx < dev->real_num_tx_queues)
120 qdisc_hash_add(qdisc, false);
121 #endif
122
123 }
124 kfree(priv->qdiscs);
125 priv->qdiscs = NULL;
126 }
127
mq_dump(struct Qdisc * sch,struct sk_buff * skb)128 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
129 {
130 struct net_device *dev = qdisc_dev(sch);
131 struct Qdisc *qdisc;
132 unsigned int ntx;
133 __u32 qlen = 0;
134
135 sch->q.qlen = 0;
136 memset(&sch->bstats, 0, sizeof(sch->bstats));
137 memset(&sch->qstats, 0, sizeof(sch->qstats));
138
139 /* MQ supports lockless qdiscs. However, statistics accounting needs
140 * to account for all, none, or a mix of locked and unlocked child
141 * qdiscs. Percpu stats are added to counters in-band and locking
142 * qdisc totals are added at end.
143 */
144 for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
145 qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
146 spin_lock_bh(qdisc_lock(qdisc));
147
148 if (qdisc_is_percpu_stats(qdisc)) {
149 qlen = qdisc_qlen_sum(qdisc);
150 __gnet_stats_copy_basic(NULL, &sch->bstats,
151 qdisc->cpu_bstats,
152 &qdisc->bstats);
153 __gnet_stats_copy_queue(&sch->qstats,
154 qdisc->cpu_qstats,
155 &qdisc->qstats, qlen);
156 sch->q.qlen += qlen;
157 } else {
158 sch->q.qlen += qdisc->q.qlen;
159 sch->bstats.bytes += qdisc->bstats.bytes;
160 sch->bstats.packets += qdisc->bstats.packets;
161 sch->qstats.qlen += qdisc->qstats.qlen;
162 sch->qstats.backlog += qdisc->qstats.backlog;
163 sch->qstats.drops += qdisc->qstats.drops;
164 sch->qstats.requeues += qdisc->qstats.requeues;
165 sch->qstats.overlimits += qdisc->qstats.overlimits;
166 }
167
168 spin_unlock_bh(qdisc_lock(qdisc));
169 }
170
171 return mq_offload_stats(sch);
172 }
173
mq_queue_get(struct Qdisc * sch,unsigned long cl)174 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
175 {
176 struct net_device *dev = qdisc_dev(sch);
177 unsigned long ntx = cl - 1;
178
179 if (ntx >= dev->num_tx_queues)
180 return NULL;
181 return netdev_get_tx_queue(dev, ntx);
182 }
183
mq_select_queue(struct Qdisc * sch,struct tcmsg * tcm)184 static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
185 struct tcmsg *tcm)
186 {
187 return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent));
188 }
189
mq_graft(struct Qdisc * sch,unsigned long cl,struct Qdisc * new,struct Qdisc ** old,struct netlink_ext_ack * extack)190 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
191 struct Qdisc **old, struct netlink_ext_ack *extack)
192 {
193 struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
194 struct tc_mq_qopt_offload graft_offload;
195 struct net_device *dev = qdisc_dev(sch);
196
197 if (dev->flags & IFF_UP)
198 dev_deactivate(dev);
199
200 *old = dev_graft_qdisc(dev_queue, new);
201 if (new)
202 new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
203 if (dev->flags & IFF_UP)
204 dev_activate(dev);
205
206 graft_offload.handle = sch->handle;
207 graft_offload.graft_params.queue = cl - 1;
208 graft_offload.graft_params.child_handle = new ? new->handle : 0;
209 graft_offload.command = TC_MQ_GRAFT;
210
211 qdisc_offload_graft_helper(qdisc_dev(sch), sch, new, *old,
212 TC_SETUP_QDISC_MQ, &graft_offload, extack);
213 return 0;
214 }
215
mq_leaf(struct Qdisc * sch,unsigned long cl)216 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
217 {
218 struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
219
220 return dev_queue->qdisc_sleeping;
221 }
222
mq_find(struct Qdisc * sch,u32 classid)223 static unsigned long mq_find(struct Qdisc *sch, u32 classid)
224 {
225 unsigned int ntx = TC_H_MIN(classid);
226
227 if (!mq_queue_get(sch, ntx))
228 return 0;
229 return ntx;
230 }
231
mq_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)232 static int mq_dump_class(struct Qdisc *sch, unsigned long cl,
233 struct sk_buff *skb, struct tcmsg *tcm)
234 {
235 struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
236
237 tcm->tcm_parent = TC_H_ROOT;
238 tcm->tcm_handle |= TC_H_MIN(cl);
239 tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
240 return 0;
241 }
242
mq_dump_class_stats(struct Qdisc * sch,unsigned long cl,struct gnet_dump * d)243 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
244 struct gnet_dump *d)
245 {
246 struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
247
248 sch = dev_queue->qdisc_sleeping;
249 if (gnet_stats_copy_basic(&sch->running, d, sch->cpu_bstats,
250 &sch->bstats) < 0 ||
251 qdisc_qstats_copy(d, sch) < 0)
252 return -1;
253 return 0;
254 }
255
mq_walk(struct Qdisc * sch,struct qdisc_walker * arg)256 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
257 {
258 struct net_device *dev = qdisc_dev(sch);
259 unsigned int ntx;
260
261 if (arg->stop)
262 return;
263
264 arg->count = arg->skip;
265 for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
266 if (arg->fn(sch, ntx + 1, arg) < 0) {
267 arg->stop = 1;
268 break;
269 }
270 arg->count++;
271 }
272 }
273
274 static const struct Qdisc_class_ops mq_class_ops = {
275 .select_queue = mq_select_queue,
276 .graft = mq_graft,
277 .leaf = mq_leaf,
278 .find = mq_find,
279 .walk = mq_walk,
280 .dump = mq_dump_class,
281 .dump_stats = mq_dump_class_stats,
282 };
283
284 struct Qdisc_ops mq_qdisc_ops __read_mostly = {
285 .cl_ops = &mq_class_ops,
286 .id = "mq",
287 .priv_size = sizeof(struct mq_sched),
288 .init = mq_init,
289 .destroy = mq_destroy,
290 .attach = mq_attach,
291 .dump = mq_dump,
292 .owner = THIS_MODULE,
293 };
294