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 | |
24 | static int mq_offload(struct Qdisc *sch, enum tc_mq_command cmd) |
25 | { |
26 | struct net_device *dev = qdisc_dev(qdisc: 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 | |
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(q: sch, type: TC_SETUP_QDISC_MQ, type_data: &opt); |
50 | } |
51 | |
52 | static void mq_destroy(struct Qdisc *sch) |
53 | { |
54 | struct net_device *dev = qdisc_dev(qdisc: sch); |
55 | struct mq_sched *priv = qdisc_priv(sch); |
56 | unsigned int ntx; |
57 | |
58 | mq_offload(sch, cmd: 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(qdisc: priv->qdiscs[ntx]); |
64 | kfree(objp: priv->qdiscs); |
65 | } |
66 | |
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(qdisc: 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(n: dev->num_tx_queues, size: 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, index: ntx); |
90 | qdisc = qdisc_create_dflt(dev_queue, ops: 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, cmd: TC_MQ_CREATE); |
103 | return 0; |
104 | } |
105 | |
106 | static void mq_attach(struct Qdisc *sch) |
107 | { |
108 | struct net_device *dev = qdisc_dev(qdisc: 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(dev_queue: qdisc->dev_queue, qdisc); |
116 | if (old) |
117 | qdisc_put(qdisc: old); |
118 | #ifdef CONFIG_NET_SCHED |
119 | if (ntx < dev->real_num_tx_queues) |
120 | qdisc_hash_add(q: qdisc, invisible: false); |
121 | #endif |
122 | |
123 | } |
124 | kfree(objp: priv->qdiscs); |
125 | priv->qdiscs = NULL; |
126 | } |
127 | |
128 | static int mq_dump(struct Qdisc *sch, struct sk_buff *skb) |
129 | { |
130 | struct net_device *dev = qdisc_dev(qdisc: sch); |
131 | struct Qdisc *qdisc; |
132 | unsigned int ntx; |
133 | |
134 | sch->q.qlen = 0; |
135 | gnet_stats_basic_sync_init(b: &sch->bstats); |
136 | memset(&sch->qstats, 0, sizeof(sch->qstats)); |
137 | |
138 | /* MQ supports lockless qdiscs. However, statistics accounting needs |
139 | * to account for all, none, or a mix of locked and unlocked child |
140 | * qdiscs. Percpu stats are added to counters in-band and locking |
141 | * qdisc totals are added at end. |
142 | */ |
143 | for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { |
144 | qdisc = rtnl_dereference(netdev_get_tx_queue(dev, ntx)->qdisc_sleeping); |
145 | spin_lock_bh(lock: qdisc_lock(qdisc)); |
146 | |
147 | gnet_stats_add_basic(bstats: &sch->bstats, cpu: qdisc->cpu_bstats, |
148 | b: &qdisc->bstats, running: false); |
149 | gnet_stats_add_queue(qstats: &sch->qstats, cpu_q: qdisc->cpu_qstats, |
150 | q: &qdisc->qstats); |
151 | sch->q.qlen += qdisc_qlen(q: qdisc); |
152 | |
153 | spin_unlock_bh(lock: qdisc_lock(qdisc)); |
154 | } |
155 | |
156 | return mq_offload_stats(sch); |
157 | } |
158 | |
159 | static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl) |
160 | { |
161 | struct net_device *dev = qdisc_dev(qdisc: sch); |
162 | unsigned long ntx = cl - 1; |
163 | |
164 | if (ntx >= dev->num_tx_queues) |
165 | return NULL; |
166 | return netdev_get_tx_queue(dev, index: ntx); |
167 | } |
168 | |
169 | static struct netdev_queue *mq_select_queue(struct Qdisc *sch, |
170 | struct tcmsg *tcm) |
171 | { |
172 | return mq_queue_get(sch, TC_H_MIN(tcm->tcm_parent)); |
173 | } |
174 | |
175 | static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new, |
176 | struct Qdisc **old, struct netlink_ext_ack *extack) |
177 | { |
178 | struct netdev_queue *dev_queue = mq_queue_get(sch, cl); |
179 | struct tc_mq_qopt_offload graft_offload; |
180 | struct net_device *dev = qdisc_dev(qdisc: sch); |
181 | |
182 | if (dev->flags & IFF_UP) |
183 | dev_deactivate(dev); |
184 | |
185 | *old = dev_graft_qdisc(dev_queue, qdisc: new); |
186 | if (new) |
187 | new->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT; |
188 | if (dev->flags & IFF_UP) |
189 | dev_activate(dev); |
190 | |
191 | graft_offload.handle = sch->handle; |
192 | graft_offload.graft_params.queue = cl - 1; |
193 | graft_offload.graft_params.child_handle = new ? new->handle : 0; |
194 | graft_offload.command = TC_MQ_GRAFT; |
195 | |
196 | qdisc_offload_graft_helper(dev: qdisc_dev(qdisc: sch), sch, new, old: *old, |
197 | type: TC_SETUP_QDISC_MQ, type_data: &graft_offload, extack); |
198 | return 0; |
199 | } |
200 | |
201 | static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl) |
202 | { |
203 | struct netdev_queue *dev_queue = mq_queue_get(sch, cl); |
204 | |
205 | return rtnl_dereference(dev_queue->qdisc_sleeping); |
206 | } |
207 | |
208 | static unsigned long mq_find(struct Qdisc *sch, u32 classid) |
209 | { |
210 | unsigned int ntx = TC_H_MIN(classid); |
211 | |
212 | if (!mq_queue_get(sch, cl: ntx)) |
213 | return 0; |
214 | return ntx; |
215 | } |
216 | |
217 | static int mq_dump_class(struct Qdisc *sch, unsigned long cl, |
218 | struct sk_buff *skb, struct tcmsg *tcm) |
219 | { |
220 | struct netdev_queue *dev_queue = mq_queue_get(sch, cl); |
221 | |
222 | tcm->tcm_parent = TC_H_ROOT; |
223 | tcm->tcm_handle |= TC_H_MIN(cl); |
224 | tcm->tcm_info = rtnl_dereference(dev_queue->qdisc_sleeping)->handle; |
225 | return 0; |
226 | } |
227 | |
228 | static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl, |
229 | struct gnet_dump *d) |
230 | { |
231 | struct netdev_queue *dev_queue = mq_queue_get(sch, cl); |
232 | |
233 | sch = rtnl_dereference(dev_queue->qdisc_sleeping); |
234 | if (gnet_stats_copy_basic(d, cpu: sch->cpu_bstats, b: &sch->bstats, running: true) < 0 || |
235 | qdisc_qstats_copy(d, sch) < 0) |
236 | return -1; |
237 | return 0; |
238 | } |
239 | |
240 | static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg) |
241 | { |
242 | struct net_device *dev = qdisc_dev(qdisc: sch); |
243 | unsigned int ntx; |
244 | |
245 | if (arg->stop) |
246 | return; |
247 | |
248 | arg->count = arg->skip; |
249 | for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) { |
250 | if (!tc_qdisc_stats_dump(sch, cl: ntx + 1, arg)) |
251 | break; |
252 | } |
253 | } |
254 | |
255 | static const struct Qdisc_class_ops mq_class_ops = { |
256 | .select_queue = mq_select_queue, |
257 | .graft = mq_graft, |
258 | .leaf = mq_leaf, |
259 | .find = mq_find, |
260 | .walk = mq_walk, |
261 | .dump = mq_dump_class, |
262 | .dump_stats = mq_dump_class_stats, |
263 | }; |
264 | |
265 | struct Qdisc_ops mq_qdisc_ops __read_mostly = { |
266 | .cl_ops = &mq_class_ops, |
267 | .id = "mq" , |
268 | .priv_size = sizeof(struct mq_sched), |
269 | .init = mq_init, |
270 | .destroy = mq_destroy, |
271 | .attach = mq_attach, |
272 | .change_real_num_tx = mq_change_real_num_tx, |
273 | .dump = mq_dump, |
274 | .owner = THIS_MODULE, |
275 | }; |
276 | |