xref: /openbmc/linux/net/sched/sch_mq.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /*
2  * net/sched/sch_mq.c		Classful multiqueue dummy scheduler
3  *
4  * Copyright (c) 2009 Patrick McHardy <kaber@trash.net>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * version 2 as published by the Free Software Foundation.
9  */
10 
11 #include <linux/types.h>
12 #include <linux/kernel.h>
13 #include <linux/string.h>
14 #include <linux/errno.h>
15 #include <linux/skbuff.h>
16 #include <net/netlink.h>
17 #include <net/pkt_sched.h>
18 
19 struct mq_sched {
20 	struct Qdisc		**qdiscs;
21 };
22 
23 static void mq_destroy(struct Qdisc *sch)
24 {
25 	struct net_device *dev = qdisc_dev(sch);
26 	struct mq_sched *priv = qdisc_priv(sch);
27 	unsigned int ntx;
28 
29 	if (!priv->qdiscs)
30 		return;
31 	for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
32 		qdisc_destroy(priv->qdiscs[ntx]);
33 	kfree(priv->qdiscs);
34 }
35 
36 static int mq_init(struct Qdisc *sch, struct nlattr *opt)
37 {
38 	struct net_device *dev = qdisc_dev(sch);
39 	struct mq_sched *priv = qdisc_priv(sch);
40 	struct netdev_queue *dev_queue;
41 	struct Qdisc *qdisc;
42 	unsigned int ntx;
43 
44 	if (sch->parent != TC_H_ROOT)
45 		return -EOPNOTSUPP;
46 
47 	if (!netif_is_multiqueue(dev))
48 		return -EOPNOTSUPP;
49 
50 	/* pre-allocate qdiscs, attachment can't fail */
51 	priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
52 			       GFP_KERNEL);
53 	if (priv->qdiscs == NULL)
54 		return -ENOMEM;
55 
56 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
57 		dev_queue = netdev_get_tx_queue(dev, ntx);
58 		qdisc = qdisc_create_dflt(dev, dev_queue, &pfifo_fast_ops,
59 					  TC_H_MAKE(TC_H_MAJ(sch->handle),
60 						    TC_H_MIN(ntx + 1)));
61 		if (qdisc == NULL)
62 			goto err;
63 		qdisc->flags |= TCQ_F_CAN_BYPASS;
64 		priv->qdiscs[ntx] = qdisc;
65 	}
66 
67 	sch->flags |= TCQ_F_MQROOT;
68 	return 0;
69 
70 err:
71 	mq_destroy(sch);
72 	return -ENOMEM;
73 }
74 
75 static void mq_attach(struct Qdisc *sch)
76 {
77 	struct net_device *dev = qdisc_dev(sch);
78 	struct mq_sched *priv = qdisc_priv(sch);
79 	struct Qdisc *qdisc;
80 	unsigned int ntx;
81 
82 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
83 		qdisc = priv->qdiscs[ntx];
84 		qdisc = dev_graft_qdisc(qdisc->dev_queue, qdisc);
85 		if (qdisc)
86 			qdisc_destroy(qdisc);
87 	}
88 	kfree(priv->qdiscs);
89 	priv->qdiscs = NULL;
90 }
91 
92 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
93 {
94 	struct net_device *dev = qdisc_dev(sch);
95 	struct Qdisc *qdisc;
96 	unsigned int ntx;
97 
98 	sch->q.qlen = 0;
99 	memset(&sch->bstats, 0, sizeof(sch->bstats));
100 	memset(&sch->qstats, 0, sizeof(sch->qstats));
101 
102 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
103 		qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
104 		spin_lock_bh(qdisc_lock(qdisc));
105 		sch->q.qlen		+= qdisc->q.qlen;
106 		sch->bstats.bytes	+= qdisc->bstats.bytes;
107 		sch->bstats.packets	+= qdisc->bstats.packets;
108 		sch->qstats.qlen	+= qdisc->qstats.qlen;
109 		sch->qstats.backlog	+= qdisc->qstats.backlog;
110 		sch->qstats.drops	+= qdisc->qstats.drops;
111 		sch->qstats.requeues	+= qdisc->qstats.requeues;
112 		sch->qstats.overlimits	+= qdisc->qstats.overlimits;
113 		spin_unlock_bh(qdisc_lock(qdisc));
114 	}
115 	return 0;
116 }
117 
118 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
119 {
120 	struct net_device *dev = qdisc_dev(sch);
121 	unsigned long ntx = cl - 1;
122 
123 	if (ntx >= dev->num_tx_queues)
124 		return NULL;
125 	return netdev_get_tx_queue(dev, ntx);
126 }
127 
128 static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
129 					    struct tcmsg *tcm)
130 {
131 	unsigned int ntx = TC_H_MIN(tcm->tcm_parent);
132 	struct netdev_queue *dev_queue = mq_queue_get(sch, ntx);
133 
134 	if (!dev_queue) {
135 		struct net_device *dev = qdisc_dev(sch);
136 
137 		return netdev_get_tx_queue(dev, 0);
138 	}
139 	return dev_queue;
140 }
141 
142 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
143 		    struct Qdisc **old)
144 {
145 	struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
146 	struct net_device *dev = qdisc_dev(sch);
147 
148 	if (dev->flags & IFF_UP)
149 		dev_deactivate(dev);
150 
151 	*old = dev_graft_qdisc(dev_queue, new);
152 
153 	if (dev->flags & IFF_UP)
154 		dev_activate(dev);
155 	return 0;
156 }
157 
158 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
159 {
160 	struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
161 
162 	return dev_queue->qdisc_sleeping;
163 }
164 
165 static unsigned long mq_get(struct Qdisc *sch, u32 classid)
166 {
167 	unsigned int ntx = TC_H_MIN(classid);
168 
169 	if (!mq_queue_get(sch, ntx))
170 		return 0;
171 	return ntx;
172 }
173 
174 static void mq_put(struct Qdisc *sch, unsigned long cl)
175 {
176 	return;
177 }
178 
179 static int mq_dump_class(struct Qdisc *sch, unsigned long cl,
180 			 struct sk_buff *skb, struct tcmsg *tcm)
181 {
182 	struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
183 
184 	tcm->tcm_parent = TC_H_ROOT;
185 	tcm->tcm_handle |= TC_H_MIN(cl);
186 	tcm->tcm_info = dev_queue->qdisc_sleeping->handle;
187 	return 0;
188 }
189 
190 static int mq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
191 			       struct gnet_dump *d)
192 {
193 	struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
194 
195 	sch = dev_queue->qdisc_sleeping;
196 	sch->qstats.qlen = sch->q.qlen;
197 	if (gnet_stats_copy_basic(d, &sch->bstats) < 0 ||
198 	    gnet_stats_copy_queue(d, &sch->qstats) < 0)
199 		return -1;
200 	return 0;
201 }
202 
203 static void mq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
204 {
205 	struct net_device *dev = qdisc_dev(sch);
206 	unsigned int ntx;
207 
208 	if (arg->stop)
209 		return;
210 
211 	arg->count = arg->skip;
212 	for (ntx = arg->skip; ntx < dev->num_tx_queues; ntx++) {
213 		if (arg->fn(sch, ntx + 1, arg) < 0) {
214 			arg->stop = 1;
215 			break;
216 		}
217 		arg->count++;
218 	}
219 }
220 
221 static const struct Qdisc_class_ops mq_class_ops = {
222 	.select_queue	= mq_select_queue,
223 	.graft		= mq_graft,
224 	.leaf		= mq_leaf,
225 	.get		= mq_get,
226 	.put		= mq_put,
227 	.walk		= mq_walk,
228 	.dump		= mq_dump_class,
229 	.dump_stats	= mq_dump_class_stats,
230 };
231 
232 struct Qdisc_ops mq_qdisc_ops __read_mostly = {
233 	.cl_ops		= &mq_class_ops,
234 	.id		= "mq",
235 	.priv_size	= sizeof(struct mq_sched),
236 	.init		= mq_init,
237 	.destroy	= mq_destroy,
238 	.attach		= mq_attach,
239 	.dump		= mq_dump,
240 	.owner		= THIS_MODULE,
241 };
242