Merge branch 'for-3.7-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-3.10.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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #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
28 #include <linux/fdtable.h>
29
30 #define PRIOIDX_SZ 128
31
32 static unsigned long prioidx_map[PRIOIDX_SZ];
33 static DEFINE_SPINLOCK(prioidx_map_lock);
34 static atomic_t max_prioidx = ATOMIC_INIT(0);
35
36 static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
37 {
38         return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
39                             struct cgroup_netprio_state, css);
40 }
41
42 static int get_prioidx(u32 *prio)
43 {
44         unsigned long flags;
45         u32 prioidx;
46
47         spin_lock_irqsave(&prioidx_map_lock, flags);
48         prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
49         if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
50                 spin_unlock_irqrestore(&prioidx_map_lock, flags);
51                 return -ENOSPC;
52         }
53         set_bit(prioidx, prioidx_map);
54         if (atomic_read(&max_prioidx) < prioidx)
55                 atomic_set(&max_prioidx, prioidx);
56         spin_unlock_irqrestore(&prioidx_map_lock, flags);
57         *prio = prioidx;
58         return 0;
59 }
60
61 static void put_prioidx(u32 idx)
62 {
63         unsigned long flags;
64
65         spin_lock_irqsave(&prioidx_map_lock, flags);
66         clear_bit(idx, prioidx_map);
67         spin_unlock_irqrestore(&prioidx_map_lock, flags);
68 }
69
70 static int extend_netdev_table(struct net_device *dev, u32 new_len)
71 {
72         size_t new_size = sizeof(struct netprio_map) +
73                            ((sizeof(u32) * new_len));
74         struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
75         struct netprio_map *old_priomap;
76         int i;
77
78         old_priomap  = rtnl_dereference(dev->priomap);
79
80         if (!new_priomap) {
81                 pr_warn("Unable to alloc new priomap!\n");
82                 return -ENOMEM;
83         }
84
85         for (i = 0;
86              old_priomap && (i < old_priomap->priomap_len);
87              i++)
88                 new_priomap->priomap[i] = old_priomap->priomap[i];
89
90         new_priomap->priomap_len = new_len;
91
92         rcu_assign_pointer(dev->priomap, new_priomap);
93         if (old_priomap)
94                 kfree_rcu(old_priomap, rcu);
95         return 0;
96 }
97
98 static int write_update_netdev_table(struct net_device *dev)
99 {
100         int ret = 0;
101         u32 max_len;
102         struct netprio_map *map;
103
104         max_len = atomic_read(&max_prioidx) + 1;
105         map = rtnl_dereference(dev->priomap);
106         if (!map || map->priomap_len < max_len)
107                 ret = extend_netdev_table(dev, max_len);
108
109         return ret;
110 }
111
112 static int update_netdev_tables(void)
113 {
114         int ret = 0;
115         struct net_device *dev;
116         u32 max_len;
117         struct netprio_map *map;
118
119         rtnl_lock();
120         max_len = atomic_read(&max_prioidx) + 1;
121         for_each_netdev(&init_net, dev) {
122                 map = rtnl_dereference(dev->priomap);
123                 /*
124                  * don't allocate priomap if we didn't
125                  * change net_prio.ifpriomap (map == NULL),
126                  * this will speed up skb_update_prio.
127                  */
128                 if (map && map->priomap_len < max_len) {
129                         ret = extend_netdev_table(dev, max_len);
130                         if (ret < 0)
131                                 break;
132                 }
133         }
134         rtnl_unlock();
135         return ret;
136 }
137
138 static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
139 {
140         struct cgroup_netprio_state *cs;
141         int ret = -EINVAL;
142
143         cs = kzalloc(sizeof(*cs), GFP_KERNEL);
144         if (!cs)
145                 return ERR_PTR(-ENOMEM);
146
147         if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx)
148                 goto out;
149
150         ret = get_prioidx(&cs->prioidx);
151         if (ret < 0) {
152                 pr_warn("No space in priority index array\n");
153                 goto out;
154         }
155
156         ret = update_netdev_tables();
157         if (ret < 0) {
158                 put_prioidx(cs->prioidx);
159                 goto out;
160         }
161
162         return &cs->css;
163 out:
164         kfree(cs);
165         return ERR_PTR(ret);
166 }
167
168 static void cgrp_destroy(struct cgroup *cgrp)
169 {
170         struct cgroup_netprio_state *cs;
171         struct net_device *dev;
172         struct netprio_map *map;
173
174         cs = cgrp_netprio_state(cgrp);
175         rtnl_lock();
176         for_each_netdev(&init_net, dev) {
177                 map = rtnl_dereference(dev->priomap);
178                 if (map && cs->prioidx < map->priomap_len)
179                         map->priomap[cs->prioidx] = 0;
180         }
181         rtnl_unlock();
182         put_prioidx(cs->prioidx);
183         kfree(cs);
184 }
185
186 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
187 {
188         return (u64)cgrp_netprio_state(cgrp)->prioidx;
189 }
190
191 static int read_priomap(struct cgroup *cont, struct cftype *cft,
192                         struct cgroup_map_cb *cb)
193 {
194         struct net_device *dev;
195         u32 prioidx = cgrp_netprio_state(cont)->prioidx;
196         u32 priority;
197         struct netprio_map *map;
198
199         rcu_read_lock();
200         for_each_netdev_rcu(&init_net, dev) {
201                 map = rcu_dereference(dev->priomap);
202                 priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;
203                 cb->fill(cb, dev->name, priority);
204         }
205         rcu_read_unlock();
206         return 0;
207 }
208
209 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
210                          const char *buffer)
211 {
212         char *devname = kstrdup(buffer, GFP_KERNEL);
213         int ret = -EINVAL;
214         u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
215         unsigned long priority;
216         char *priostr;
217         struct net_device *dev;
218         struct netprio_map *map;
219
220         if (!devname)
221                 return -ENOMEM;
222
223         /*
224          * Minimally sized valid priomap string
225          */
226         if (strlen(devname) < 3)
227                 goto out_free_devname;
228
229         priostr = strstr(devname, " ");
230         if (!priostr)
231                 goto out_free_devname;
232
233         /*
234          *Separate the devname from the associated priority
235          *and advance the priostr pointer to the priority value
236          */
237         *priostr = '\0';
238         priostr++;
239
240         /*
241          * If the priostr points to NULL, we're at the end of the passed
242          * in string, and its not a valid write
243          */
244         if (*priostr == '\0')
245                 goto out_free_devname;
246
247         ret = kstrtoul(priostr, 10, &priority);
248         if (ret < 0)
249                 goto out_free_devname;
250
251         ret = -ENODEV;
252
253         dev = dev_get_by_name(&init_net, devname);
254         if (!dev)
255                 goto out_free_devname;
256
257         rtnl_lock();
258         ret = write_update_netdev_table(dev);
259         if (ret < 0)
260                 goto out_put_dev;
261
262         map = rtnl_dereference(dev->priomap);
263         if (map)
264                 map->priomap[prioidx] = priority;
265
266 out_put_dev:
267         rtnl_unlock();
268         dev_put(dev);
269
270 out_free_devname:
271         kfree(devname);
272         return ret;
273 }
274
275 void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
276 {
277         struct task_struct *p;
278
279         cgroup_taskset_for_each(p, cgrp, tset) {
280                 unsigned int fd;
281                 struct fdtable *fdt;
282                 struct files_struct *files;
283
284                 task_lock(p);
285                 files = p->files;
286                 if (!files) {
287                         task_unlock(p);
288                         continue;
289                 }
290
291                 spin_lock(&files->file_lock);
292                 fdt = files_fdtable(files);
293                 for (fd = 0; fd < fdt->max_fds; fd++) {
294                         struct file *file;
295                         struct socket *sock;
296                         int err;
297
298                         file = fcheck_files(files, fd);
299                         if (!file)
300                                 continue;
301
302                         sock = sock_from_file(file, &err);
303                         if (sock)
304                                 sock_update_netprioidx(sock->sk, p);
305                 }
306                 spin_unlock(&files->file_lock);
307                 task_unlock(p);
308         }
309 }
310
311 static struct cftype ss_files[] = {
312         {
313                 .name = "prioidx",
314                 .read_u64 = read_prioidx,
315         },
316         {
317                 .name = "ifpriomap",
318                 .read_map = read_priomap,
319                 .write_string = write_priomap,
320         },
321         { }     /* terminate */
322 };
323
324 struct cgroup_subsys net_prio_subsys = {
325         .name           = "net_prio",
326         .create         = cgrp_create,
327         .destroy        = cgrp_destroy,
328         .attach         = net_prio_attach,
329         .subsys_id      = net_prio_subsys_id,
330         .base_cftypes   = ss_files,
331         .module         = THIS_MODULE,
332
333         /*
334          * net_prio has artificial limit on the number of cgroups and
335          * disallows nesting making it impossible to co-mount it with other
336          * hierarchical subsystems.  Remove the artificially low PRIOIDX_SZ
337          * limit and properly nest configuration such that children follow
338          * their parents' configurations by default and are allowed to
339          * override and remove the following.
340          */
341         .broken_hierarchy = true,
342 };
343
344 static int netprio_device_event(struct notifier_block *unused,
345                                 unsigned long event, void *ptr)
346 {
347         struct net_device *dev = ptr;
348         struct netprio_map *old;
349
350         /*
351          * Note this is called with rtnl_lock held so we have update side
352          * protection on our rcu assignments
353          */
354
355         switch (event) {
356         case NETDEV_UNREGISTER:
357                 old = rtnl_dereference(dev->priomap);
358                 RCU_INIT_POINTER(dev->priomap, NULL);
359                 if (old)
360                         kfree_rcu(old, rcu);
361                 break;
362         }
363         return NOTIFY_DONE;
364 }
365
366 static struct notifier_block netprio_device_notifier = {
367         .notifier_call = netprio_device_event
368 };
369
370 static int __init init_cgroup_netprio(void)
371 {
372         int ret;
373
374         ret = cgroup_load_subsys(&net_prio_subsys);
375         if (ret)
376                 goto out;
377
378         register_netdevice_notifier(&netprio_device_notifier);
379
380 out:
381         return ret;
382 }
383
384 static void __exit exit_cgroup_netprio(void)
385 {
386         struct netprio_map *old;
387         struct net_device *dev;
388
389         unregister_netdevice_notifier(&netprio_device_notifier);
390
391         cgroup_unload_subsys(&net_prio_subsys);
392
393         rtnl_lock();
394         for_each_netdev(&init_net, dev) {
395                 old = rtnl_dereference(dev->priomap);
396                 RCU_INIT_POINTER(dev->priomap, NULL);
397                 if (old)
398                         kfree_rcu(old, rcu);
399         }
400         rtnl_unlock();
401 }
402
403 module_init(init_cgroup_netprio);
404 module_exit(exit_cgroup_netprio);
405 MODULE_LICENSE("GPL v2");