Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[linux-2.6.git] / net / core / netprio_cgroup.c
1 /*
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
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/types.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/skbuff.h>
18 #include <linux/cgroup.h>
19 #include <linux/rcupdate.h>
20 #include <linux/atomic.h>
21 #include <net/rtnetlink.h>
22 #include <net/pkt_cls.h>
23 #include <net/sock.h>
24 #include <net/netprio_cgroup.h>
25
26 static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
27                                                struct cgroup *cgrp);
28 static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
29 static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp);
30
31 struct cgroup_subsys net_prio_subsys = {
32         .name           = "net_prio",
33         .create         = cgrp_create,
34         .destroy        = cgrp_destroy,
35         .populate       = cgrp_populate,
36 #ifdef CONFIG_NETPRIO_CGROUP
37         .subsys_id      = net_prio_subsys_id,
38 #endif
39         .module         = THIS_MODULE
40 };
41
42 #define PRIOIDX_SZ 128
43
44 static unsigned long prioidx_map[PRIOIDX_SZ];
45 static DEFINE_SPINLOCK(prioidx_map_lock);
46 static atomic_t max_prioidx = ATOMIC_INIT(0);
47
48 static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
49 {
50         return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
51                             struct cgroup_netprio_state, css);
52 }
53
54 static int get_prioidx(u32 *prio)
55 {
56         unsigned long flags;
57         u32 prioidx;
58
59         spin_lock_irqsave(&prioidx_map_lock, flags);
60         prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
61         set_bit(prioidx, prioidx_map);
62         spin_unlock_irqrestore(&prioidx_map_lock, flags);
63         if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ)
64                 return -ENOSPC;
65
66         atomic_set(&max_prioidx, prioidx);
67         *prio = prioidx;
68         return 0;
69 }
70
71 static void put_prioidx(u32 idx)
72 {
73         unsigned long flags;
74
75         spin_lock_irqsave(&prioidx_map_lock, flags);
76         clear_bit(idx, prioidx_map);
77         spin_unlock_irqrestore(&prioidx_map_lock, flags);
78 }
79
80 static void extend_netdev_table(struct net_device *dev, u32 new_len)
81 {
82         size_t new_size = sizeof(struct netprio_map) +
83                            ((sizeof(u32) * new_len));
84         struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
85         struct netprio_map *old_priomap;
86         int i;
87
88         old_priomap  = rtnl_dereference(dev->priomap);
89
90         if (!new_priomap) {
91                 printk(KERN_WARNING "Unable to alloc new priomap!\n");
92                 return;
93         }
94
95         for (i = 0;
96              old_priomap && (i < old_priomap->priomap_len);
97              i++)
98                 new_priomap->priomap[i] = old_priomap->priomap[i];
99
100         new_priomap->priomap_len = new_len;
101
102         rcu_assign_pointer(dev->priomap, new_priomap);
103         if (old_priomap)
104                 kfree_rcu(old_priomap, rcu);
105 }
106
107 static void update_netdev_tables(void)
108 {
109         struct net_device *dev;
110         u32 max_len = atomic_read(&max_prioidx);
111         struct netprio_map *map;
112
113         rtnl_lock();
114         for_each_netdev(&init_net, dev) {
115                 map = rtnl_dereference(dev->priomap);
116                 if ((!map) ||
117                     (map->priomap_len < max_len))
118                         extend_netdev_table(dev, max_len);
119         }
120         rtnl_unlock();
121 }
122
123 static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
124                                                  struct cgroup *cgrp)
125 {
126         struct cgroup_netprio_state *cs;
127         int ret;
128
129         cs = kzalloc(sizeof(*cs), GFP_KERNEL);
130         if (!cs)
131                 return ERR_PTR(-ENOMEM);
132
133         if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) {
134                 kfree(cs);
135                 return ERR_PTR(-EINVAL);
136         }
137
138         ret = get_prioidx(&cs->prioidx);
139         if (ret != 0) {
140                 printk(KERN_WARNING "No space in priority index array\n");
141                 kfree(cs);
142                 return ERR_PTR(ret);
143         }
144
145         return &cs->css;
146 }
147
148 static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
149 {
150         struct cgroup_netprio_state *cs;
151         struct net_device *dev;
152         struct netprio_map *map;
153
154         cs = cgrp_netprio_state(cgrp);
155         rtnl_lock();
156         for_each_netdev(&init_net, dev) {
157                 map = rtnl_dereference(dev->priomap);
158                 if (map)
159                         map->priomap[cs->prioidx] = 0;
160         }
161         rtnl_unlock();
162         put_prioidx(cs->prioidx);
163         kfree(cs);
164 }
165
166 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
167 {
168         return (u64)cgrp_netprio_state(cgrp)->prioidx;
169 }
170
171 static int read_priomap(struct cgroup *cont, struct cftype *cft,
172                         struct cgroup_map_cb *cb)
173 {
174         struct net_device *dev;
175         u32 prioidx = cgrp_netprio_state(cont)->prioidx;
176         u32 priority;
177         struct netprio_map *map;
178
179         rcu_read_lock();
180         for_each_netdev_rcu(&init_net, dev) {
181                 map = rcu_dereference(dev->priomap);
182                 priority = map ? map->priomap[prioidx] : 0;
183                 cb->fill(cb, dev->name, priority);
184         }
185         rcu_read_unlock();
186         return 0;
187 }
188
189 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
190                          const char *buffer)
191 {
192         char *devname = kstrdup(buffer, GFP_KERNEL);
193         int ret = -EINVAL;
194         u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
195         unsigned long priority;
196         char *priostr;
197         struct net_device *dev;
198         struct netprio_map *map;
199
200         if (!devname)
201                 return -ENOMEM;
202
203         /*
204          * Minimally sized valid priomap string
205          */
206         if (strlen(devname) < 3)
207                 goto out_free_devname;
208
209         priostr = strstr(devname, " ");
210         if (!priostr)
211                 goto out_free_devname;
212
213         /*
214          *Separate the devname from the associated priority
215          *and advance the priostr poitner to the priority value
216          */
217         *priostr = '\0';
218         priostr++;
219
220         /*
221          * If the priostr points to NULL, we're at the end of the passed
222          * in string, and its not a valid write
223          */
224         if (*priostr == '\0')
225                 goto out_free_devname;
226
227         ret = kstrtoul(priostr, 10, &priority);
228         if (ret < 0)
229                 goto out_free_devname;
230
231         ret = -ENODEV;
232
233         dev = dev_get_by_name(&init_net, devname);
234         if (!dev)
235                 goto out_free_devname;
236
237         update_netdev_tables();
238         ret = 0;
239         rcu_read_lock();
240         map = rcu_dereference(dev->priomap);
241         if (map)
242                 map->priomap[prioidx] = priority;
243         rcu_read_unlock();
244         dev_put(dev);
245
246 out_free_devname:
247         kfree(devname);
248         return ret;
249 }
250
251 static struct cftype ss_files[] = {
252         {
253                 .name = "prioidx",
254                 .read_u64 = read_prioidx,
255         },
256         {
257                 .name = "ifpriomap",
258                 .read_map = read_priomap,
259                 .write_string = write_priomap,
260         },
261 };
262
263 static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
264 {
265         return cgroup_add_files(cgrp, ss, ss_files, ARRAY_SIZE(ss_files));
266 }
267
268 static int netprio_device_event(struct notifier_block *unused,
269                                 unsigned long event, void *ptr)
270 {
271         struct net_device *dev = ptr;
272         struct netprio_map *old;
273         u32 max_len = atomic_read(&max_prioidx);
274
275         /*
276          * Note this is called with rtnl_lock held so we have update side
277          * protection on our rcu assignments
278          */
279
280         switch (event) {
281
282         case NETDEV_REGISTER:
283                 if (max_len)
284                         extend_netdev_table(dev, max_len);
285                 break;
286         case NETDEV_UNREGISTER:
287                 old = rtnl_dereference(dev->priomap);
288                 RCU_INIT_POINTER(dev->priomap, NULL);
289                 if (old)
290                         kfree_rcu(old, rcu);
291                 break;
292         }
293         return NOTIFY_DONE;
294 }
295
296 static struct notifier_block netprio_device_notifier = {
297         .notifier_call = netprio_device_event
298 };
299
300 static int __init init_cgroup_netprio(void)
301 {
302         int ret;
303
304         ret = cgroup_load_subsys(&net_prio_subsys);
305         if (ret)
306                 goto out;
307 #ifndef CONFIG_NETPRIO_CGROUP
308         smp_wmb();
309         net_prio_subsys_id = net_prio_subsys.subsys_id;
310 #endif
311
312         register_netdevice_notifier(&netprio_device_notifier);
313
314 out:
315         return ret;
316 }
317
318 static void __exit exit_cgroup_netprio(void)
319 {
320         struct netprio_map *old;
321         struct net_device *dev;
322
323         unregister_netdevice_notifier(&netprio_device_notifier);
324
325         cgroup_unload_subsys(&net_prio_subsys);
326
327 #ifndef CONFIG_NETPRIO_CGROUP
328         net_prio_subsys_id = -1;
329         synchronize_rcu();
330 #endif
331
332         rtnl_lock();
333         for_each_netdev(&init_net, dev) {
334                 old = rtnl_dereference(dev->priomap);
335                 RCU_INIT_POINTER(dev->priomap, NULL);
336                 if (old)
337                         kfree_rcu(old, rcu);
338         }
339         rtnl_unlock();
340 }
341
342 module_init(init_cgroup_netprio);
343 module_exit(exit_cgroup_netprio);
344 MODULE_LICENSE("GPL v2");