xref: /linux/net/sched/sch_mq.c (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)
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 
134 	sch->q.qlen = 0;
135 	gnet_stats_basic_sync_init(&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(qdisc_lock(qdisc));
146 
147 		gnet_stats_add_basic(&sch->bstats, qdisc->cpu_bstats,
148 				     &qdisc->bstats, false);
149 		gnet_stats_add_queue(&sch->qstats, qdisc->cpu_qstats,
150 				     &qdisc->qstats);
151 		sch->q.qlen += qdisc_qlen(qdisc);
152 
153 		spin_unlock_bh(qdisc_lock(qdisc));
154 	}
155 
156 	return mq_offload_stats(sch);
157 }
158 
mq_queue_get(struct Qdisc * sch,unsigned long cl)159 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
160 {
161 	struct net_device *dev = qdisc_dev(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, ntx);
167 }
168 
mq_select_queue(struct Qdisc * sch,struct tcmsg * tcm)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 
mq_graft(struct Qdisc * sch,unsigned long cl,struct Qdisc * new,struct Qdisc ** old,struct netlink_ext_ack * extack)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(sch);
181 
182 	if (dev->flags & IFF_UP)
183 		dev_deactivate(dev);
184 
185 	*old = dev_graft_qdisc(dev_queue, 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(qdisc_dev(sch), sch, new, *old,
197 				   TC_SETUP_QDISC_MQ, &graft_offload, extack);
198 	return 0;
199 }
200 
mq_leaf(struct Qdisc * sch,unsigned long cl)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 
mq_find(struct Qdisc * sch,u32 classid)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, ntx))
213 		return 0;
214 	return ntx;
215 }
216 
mq_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)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 
mq_dump_class_stats(struct Qdisc * sch,unsigned long cl,struct gnet_dump * d)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, sch->cpu_bstats, &sch->bstats, true) < 0 ||
235 	    qdisc_qstats_copy(d, sch) < 0)
236 		return -1;
237 	return 0;
238 }
239 
mq_walk(struct Qdisc * sch,struct qdisc_walker * arg)240 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
241 {
242 	struct net_device *dev = qdisc_dev(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, 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