Linux Kernel  3.7.1
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sch_mq.c
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1 /*
2  * net/sched/sch_mq.c Classful multiqueue dummy scheduler
3  *
4  * Copyright (c) 2009 Patrick McHardy <[email protected]>
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/slab.h>
13 #include <linux/kernel.h>
14 #include <linux/export.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/skbuff.h>
18 #include <net/netlink.h>
19 #include <net/pkt_sched.h>
20 
21 struct mq_sched {
22  struct Qdisc **qdiscs;
23 };
24 
25 static void mq_destroy(struct Qdisc *sch)
26 {
27  struct net_device *dev = qdisc_dev(sch);
28  struct mq_sched *priv = qdisc_priv(sch);
29  unsigned int ntx;
30 
31  if (!priv->qdiscs)
32  return;
33  for (ntx = 0; ntx < dev->num_tx_queues && priv->qdiscs[ntx]; ntx++)
34  qdisc_destroy(priv->qdiscs[ntx]);
35  kfree(priv->qdiscs);
36 }
37 
38 static int mq_init(struct Qdisc *sch, struct nlattr *opt)
39 {
40  struct net_device *dev = qdisc_dev(sch);
41  struct mq_sched *priv = qdisc_priv(sch);
42  struct netdev_queue *dev_queue;
43  struct Qdisc *qdisc;
44  unsigned int ntx;
45 
46  if (sch->parent != TC_H_ROOT)
47  return -EOPNOTSUPP;
48 
49  if (!netif_is_multiqueue(dev))
50  return -EOPNOTSUPP;
51 
52  /* pre-allocate qdiscs, attachment can't fail */
53  priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
54  GFP_KERNEL);
55  if (priv->qdiscs == NULL)
56  return -ENOMEM;
57 
58  for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
59  dev_queue = netdev_get_tx_queue(dev, ntx);
60  qdisc = qdisc_create_dflt(dev_queue, &pfifo_fast_ops,
62  TC_H_MIN(ntx + 1)));
63  if (qdisc == NULL)
64  goto err;
65  priv->qdiscs[ntx] = qdisc;
66  }
67 
68  sch->flags |= TCQ_F_MQROOT;
69  return 0;
70 
71 err:
72  mq_destroy(sch);
73  return -ENOMEM;
74 }
75 
76 static void mq_attach(struct Qdisc *sch)
77 {
78  struct net_device *dev = qdisc_dev(sch);
79  struct mq_sched *priv = qdisc_priv(sch);
80  struct Qdisc *qdisc;
81  unsigned int ntx;
82 
83  for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
84  qdisc = priv->qdiscs[ntx];
85  qdisc = dev_graft_qdisc(qdisc->dev_queue, qdisc);
86  if (qdisc)
87  qdisc_destroy(qdisc);
88  }
89  kfree(priv->qdiscs);
90  priv->qdiscs = NULL;
91 }
92 
93 static int mq_dump(struct Qdisc *sch, struct sk_buff *skb)
94 {
95  struct net_device *dev = qdisc_dev(sch);
96  struct Qdisc *qdisc;
97  unsigned int ntx;
98 
99  sch->q.qlen = 0;
100  memset(&sch->bstats, 0, sizeof(sch->bstats));
101  memset(&sch->qstats, 0, sizeof(sch->qstats));
102 
103  for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
104  qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
105  spin_lock_bh(qdisc_lock(qdisc));
106  sch->q.qlen += qdisc->q.qlen;
107  sch->bstats.bytes += qdisc->bstats.bytes;
108  sch->bstats.packets += qdisc->bstats.packets;
109  sch->qstats.qlen += qdisc->qstats.qlen;
110  sch->qstats.backlog += qdisc->qstats.backlog;
111  sch->qstats.drops += qdisc->qstats.drops;
112  sch->qstats.requeues += qdisc->qstats.requeues;
113  sch->qstats.overlimits += qdisc->qstats.overlimits;
114  spin_unlock_bh(qdisc_lock(qdisc));
115  }
116  return 0;
117 }
118 
119 static struct netdev_queue *mq_queue_get(struct Qdisc *sch, unsigned long cl)
120 {
121  struct net_device *dev = qdisc_dev(sch);
122  unsigned long ntx = cl - 1;
123 
124  if (ntx >= dev->num_tx_queues)
125  return NULL;
126  return netdev_get_tx_queue(dev, ntx);
127 }
128 
129 static struct netdev_queue *mq_select_queue(struct Qdisc *sch,
130  struct tcmsg *tcm)
131 {
132  unsigned int ntx = TC_H_MIN(tcm->tcm_parent);
133  struct netdev_queue *dev_queue = mq_queue_get(sch, ntx);
134 
135  if (!dev_queue) {
136  struct net_device *dev = qdisc_dev(sch);
137 
138  return netdev_get_tx_queue(dev, 0);
139  }
140  return dev_queue;
141 }
142 
143 static int mq_graft(struct Qdisc *sch, unsigned long cl, struct Qdisc *new,
144  struct Qdisc **old)
145 {
146  struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
147  struct net_device *dev = qdisc_dev(sch);
148 
149  if (dev->flags & IFF_UP)
150  dev_deactivate(dev);
151 
152  *old = dev_graft_qdisc(dev_queue, new);
153 
154  if (dev->flags & IFF_UP)
155  dev_activate(dev);
156  return 0;
157 }
158 
159 static struct Qdisc *mq_leaf(struct Qdisc *sch, unsigned long cl)
160 {
161  struct netdev_queue *dev_queue = mq_queue_get(sch, cl);
162 
163  return dev_queue->qdisc_sleeping;
164 }
165 
166 static unsigned long mq_get(struct Qdisc *sch, u32 classid)
167 {
168  unsigned int ntx = TC_H_MIN(classid);
169 
170  if (!mq_queue_get(sch, ntx))
171  return 0;
172  return ntx;
173 }
174 
175 static void mq_put(struct Qdisc *sch, unsigned long cl)
176 {
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 
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 };