blob: 5b8aa2fae48b84e3255ecdfe83535457bd170901 [file] [log] [blame]
Neil Horman5bc14212011-11-22 05:10:51 +00001/*
2 * net/core/netprio_cgroup.c Priority Control Group
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * Authors: Neil Horman <nhorman@tuxdriver.com>
10 */
11
Joe Perchese005d192012-05-16 19:58:40 +000012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
Neil Horman5bc14212011-11-22 05:10:51 +000014#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/types.h>
17#include <linux/string.h>
18#include <linux/errno.h>
19#include <linux/skbuff.h>
20#include <linux/cgroup.h>
21#include <linux/rcupdate.h>
22#include <linux/atomic.h>
23#include <net/rtnetlink.h>
24#include <net/pkt_cls.h>
25#include <net/sock.h>
26#include <net/netprio_cgroup.h>
27
Neil Horman5bc14212011-11-22 05:10:51 +000028#define PRIOIDX_SZ 128
29
30static unsigned long prioidx_map[PRIOIDX_SZ];
31static DEFINE_SPINLOCK(prioidx_map_lock);
32static atomic_t max_prioidx = ATOMIC_INIT(0);
33
34static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
35{
36 return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
37 struct cgroup_netprio_state, css);
38}
39
40static int get_prioidx(u32 *prio)
41{
42 unsigned long flags;
43 u32 prioidx;
44
45 spin_lock_irqsave(&prioidx_map_lock, flags);
46 prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
Neil Horman5962b352012-02-03 05:18:43 +000047 if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
48 spin_unlock_irqrestore(&prioidx_map_lock, flags);
49 return -ENOSPC;
50 }
Neil Horman5bc14212011-11-22 05:10:51 +000051 set_bit(prioidx, prioidx_map);
52 spin_unlock_irqrestore(&prioidx_map_lock, flags);
Neil Horman5bc14212011-11-22 05:10:51 +000053 atomic_set(&max_prioidx, prioidx);
54 *prio = prioidx;
55 return 0;
56}
57
58static void put_prioidx(u32 idx)
59{
60 unsigned long flags;
61
62 spin_lock_irqsave(&prioidx_map_lock, flags);
63 clear_bit(idx, prioidx_map);
64 spin_unlock_irqrestore(&prioidx_map_lock, flags);
65}
66
67static void extend_netdev_table(struct net_device *dev, u32 new_len)
68{
69 size_t new_size = sizeof(struct netprio_map) +
70 ((sizeof(u32) * new_len));
71 struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
72 struct netprio_map *old_priomap;
73 int i;
74
75 old_priomap = rtnl_dereference(dev->priomap);
76
77 if (!new_priomap) {
Joe Perchese005d192012-05-16 19:58:40 +000078 pr_warn("Unable to alloc new priomap!\n");
Neil Horman5bc14212011-11-22 05:10:51 +000079 return;
80 }
81
82 for (i = 0;
83 old_priomap && (i < old_priomap->priomap_len);
84 i++)
85 new_priomap->priomap[i] = old_priomap->priomap[i];
86
87 new_priomap->priomap_len = new_len;
88
89 rcu_assign_pointer(dev->priomap, new_priomap);
90 if (old_priomap)
91 kfree_rcu(old_priomap, rcu);
92}
93
94static void update_netdev_tables(void)
95{
96 struct net_device *dev;
Neil Hormana87dfe12012-02-10 05:43:36 +000097 u32 max_len = atomic_read(&max_prioidx) + 1;
Neil Horman5bc14212011-11-22 05:10:51 +000098 struct netprio_map *map;
99
100 rtnl_lock();
101 for_each_netdev(&init_net, dev) {
102 map = rtnl_dereference(dev->priomap);
103 if ((!map) ||
104 (map->priomap_len < max_len))
105 extend_netdev_table(dev, max_len);
106 }
107 rtnl_unlock();
108}
109
Li Zefan761b3ef2012-01-31 13:47:36 +0800110static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
Neil Horman5bc14212011-11-22 05:10:51 +0000111{
112 struct cgroup_netprio_state *cs;
113 int ret;
114
115 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
116 if (!cs)
117 return ERR_PTR(-ENOMEM);
118
119 if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) {
120 kfree(cs);
121 return ERR_PTR(-EINVAL);
122 }
123
124 ret = get_prioidx(&cs->prioidx);
125 if (ret != 0) {
Joe Perchese005d192012-05-16 19:58:40 +0000126 pr_warn("No space in priority index array\n");
Neil Horman5bc14212011-11-22 05:10:51 +0000127 kfree(cs);
128 return ERR_PTR(ret);
129 }
130
131 return &cs->css;
132}
133
Li Zefan761b3ef2012-01-31 13:47:36 +0800134static void cgrp_destroy(struct cgroup *cgrp)
Neil Horman5bc14212011-11-22 05:10:51 +0000135{
136 struct cgroup_netprio_state *cs;
137 struct net_device *dev;
138 struct netprio_map *map;
139
140 cs = cgrp_netprio_state(cgrp);
141 rtnl_lock();
142 for_each_netdev(&init_net, dev) {
143 map = rtnl_dereference(dev->priomap);
144 if (map)
145 map->priomap[cs->prioidx] = 0;
146 }
147 rtnl_unlock();
148 put_prioidx(cs->prioidx);
149 kfree(cs);
150}
151
152static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
153{
154 return (u64)cgrp_netprio_state(cgrp)->prioidx;
155}
156
157static int read_priomap(struct cgroup *cont, struct cftype *cft,
158 struct cgroup_map_cb *cb)
159{
160 struct net_device *dev;
161 u32 prioidx = cgrp_netprio_state(cont)->prioidx;
162 u32 priority;
163 struct netprio_map *map;
164
165 rcu_read_lock();
166 for_each_netdev_rcu(&init_net, dev) {
167 map = rcu_dereference(dev->priomap);
168 priority = map ? map->priomap[prioidx] : 0;
169 cb->fill(cb, dev->name, priority);
170 }
171 rcu_read_unlock();
172 return 0;
173}
174
175static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
176 const char *buffer)
177{
178 char *devname = kstrdup(buffer, GFP_KERNEL);
179 int ret = -EINVAL;
180 u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
181 unsigned long priority;
182 char *priostr;
183 struct net_device *dev;
184 struct netprio_map *map;
185
186 if (!devname)
187 return -ENOMEM;
188
189 /*
190 * Minimally sized valid priomap string
191 */
192 if (strlen(devname) < 3)
193 goto out_free_devname;
194
195 priostr = strstr(devname, " ");
196 if (!priostr)
197 goto out_free_devname;
198
199 /*
200 *Separate the devname from the associated priority
201 *and advance the priostr poitner to the priority value
202 */
203 *priostr = '\0';
204 priostr++;
205
206 /*
207 * If the priostr points to NULL, we're at the end of the passed
208 * in string, and its not a valid write
209 */
210 if (*priostr == '\0')
211 goto out_free_devname;
212
213 ret = kstrtoul(priostr, 10, &priority);
214 if (ret < 0)
215 goto out_free_devname;
216
217 ret = -ENODEV;
218
219 dev = dev_get_by_name(&init_net, devname);
220 if (!dev)
221 goto out_free_devname;
222
223 update_netdev_tables();
224 ret = 0;
225 rcu_read_lock();
226 map = rcu_dereference(dev->priomap);
227 if (map)
228 map->priomap[prioidx] = priority;
229 rcu_read_unlock();
230 dev_put(dev);
231
232out_free_devname:
233 kfree(devname);
234 return ret;
235}
236
237static struct cftype ss_files[] = {
238 {
239 .name = "prioidx",
240 .read_u64 = read_prioidx,
241 },
242 {
243 .name = "ifpriomap",
244 .read_map = read_priomap,
245 .write_string = write_priomap,
246 },
Tejun Heo4baf6e32012-04-01 12:09:55 -0700247 { } /* terminate */
Neil Horman5bc14212011-11-22 05:10:51 +0000248};
249
Tejun Heo676f7c82012-04-01 12:09:55 -0700250struct cgroup_subsys net_prio_subsys = {
251 .name = "net_prio",
252 .create = cgrp_create,
253 .destroy = cgrp_destroy,
Tejun Heo676f7c82012-04-01 12:09:55 -0700254#ifdef CONFIG_NETPRIO_CGROUP
255 .subsys_id = net_prio_subsys_id,
256#endif
Tejun Heo4baf6e32012-04-01 12:09:55 -0700257 .base_cftypes = ss_files,
Tejun Heo676f7c82012-04-01 12:09:55 -0700258 .module = THIS_MODULE
259};
Neil Horman5bc14212011-11-22 05:10:51 +0000260
261static int netprio_device_event(struct notifier_block *unused,
262 unsigned long event, void *ptr)
263{
264 struct net_device *dev = ptr;
265 struct netprio_map *old;
Neil Horman5bc14212011-11-22 05:10:51 +0000266
267 /*
268 * Note this is called with rtnl_lock held so we have update side
269 * protection on our rcu assignments
270 */
271
272 switch (event) {
Neil Horman5bc14212011-11-22 05:10:51 +0000273 case NETDEV_UNREGISTER:
274 old = rtnl_dereference(dev->priomap);
Eric Dumazet2cfa5a02011-11-23 07:09:32 +0000275 RCU_INIT_POINTER(dev->priomap, NULL);
Neil Horman5bc14212011-11-22 05:10:51 +0000276 if (old)
277 kfree_rcu(old, rcu);
278 break;
279 }
280 return NOTIFY_DONE;
281}
282
283static struct notifier_block netprio_device_notifier = {
284 .notifier_call = netprio_device_event
285};
286
287static int __init init_cgroup_netprio(void)
288{
289 int ret;
290
291 ret = cgroup_load_subsys(&net_prio_subsys);
292 if (ret)
293 goto out;
294#ifndef CONFIG_NETPRIO_CGROUP
295 smp_wmb();
296 net_prio_subsys_id = net_prio_subsys.subsys_id;
297#endif
298
299 register_netdevice_notifier(&netprio_device_notifier);
300
301out:
302 return ret;
303}
304
305static void __exit exit_cgroup_netprio(void)
306{
307 struct netprio_map *old;
308 struct net_device *dev;
309
310 unregister_netdevice_notifier(&netprio_device_notifier);
311
312 cgroup_unload_subsys(&net_prio_subsys);
313
314#ifndef CONFIG_NETPRIO_CGROUP
315 net_prio_subsys_id = -1;
316 synchronize_rcu();
317#endif
318
319 rtnl_lock();
320 for_each_netdev(&init_net, dev) {
321 old = rtnl_dereference(dev->priomap);
Eric Dumazet2cfa5a02011-11-23 07:09:32 +0000322 RCU_INIT_POINTER(dev->priomap, NULL);
Neil Horman5bc14212011-11-22 05:10:51 +0000323 if (old)
324 kfree_rcu(old, rcu);
325 }
326 rtnl_unlock();
327}
328
329module_init(init_cgroup_netprio);
330module_exit(exit_cgroup_netprio);
331MODULE_LICENSE("GPL v2");