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5bc1421e NH |
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 | ||
e005d193 JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
5bc1421e NH |
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 | ||
406a3c63 JF |
28 | #include <linux/fdtable.h> |
29 | ||
5bc1421e NH |
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); | |
5962b35c NH |
49 | if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) { |
50 | spin_unlock_irqrestore(&prioidx_map_lock, flags); | |
51 | return -ENOSPC; | |
52 | } | |
5bc1421e | 53 | set_bit(prioidx, prioidx_map); |
b761c9b1 G |
54 | if (atomic_read(&max_prioidx) < prioidx) |
55 | atomic_set(&max_prioidx, prioidx); | |
5bc1421e | 56 | spin_unlock_irqrestore(&prioidx_map_lock, flags); |
5bc1421e NH |
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 | ||
ef209f15 | 70 | static int extend_netdev_table(struct net_device *dev, u32 new_len) |
5bc1421e NH |
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) { | |
e005d193 | 81 | pr_warn("Unable to alloc new priomap!\n"); |
ef209f15 | 82 | return -ENOMEM; |
5bc1421e NH |
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); | |
ef209f15 G |
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 | rtnl_lock(); | |
105 | max_len = atomic_read(&max_prioidx) + 1; | |
106 | map = rtnl_dereference(dev->priomap); | |
107 | if (!map || map->priomap_len < max_len) | |
108 | ret = extend_netdev_table(dev, max_len); | |
109 | rtnl_unlock(); | |
110 | ||
111 | return ret; | |
5bc1421e NH |
112 | } |
113 | ||
ef209f15 | 114 | static int update_netdev_tables(void) |
5bc1421e | 115 | { |
ef209f15 | 116 | int ret = 0; |
5bc1421e | 117 | struct net_device *dev; |
ef209f15 | 118 | u32 max_len; |
5bc1421e NH |
119 | struct netprio_map *map; |
120 | ||
121 | rtnl_lock(); | |
ef209f15 | 122 | max_len = atomic_read(&max_prioidx) + 1; |
5bc1421e NH |
123 | for_each_netdev(&init_net, dev) { |
124 | map = rtnl_dereference(dev->priomap); | |
ef209f15 G |
125 | /* |
126 | * don't allocate priomap if we didn't | |
127 | * change net_prio.ifpriomap (map == NULL), | |
128 | * this will speed up skb_update_prio. | |
129 | */ | |
130 | if (map && map->priomap_len < max_len) { | |
131 | ret = extend_netdev_table(dev, max_len); | |
132 | if (ret < 0) | |
133 | break; | |
134 | } | |
5bc1421e NH |
135 | } |
136 | rtnl_unlock(); | |
ef209f15 | 137 | return ret; |
5bc1421e NH |
138 | } |
139 | ||
761b3ef5 | 140 | static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp) |
5bc1421e NH |
141 | { |
142 | struct cgroup_netprio_state *cs; | |
ef209f15 | 143 | int ret = -EINVAL; |
5bc1421e NH |
144 | |
145 | cs = kzalloc(sizeof(*cs), GFP_KERNEL); | |
146 | if (!cs) | |
147 | return ERR_PTR(-ENOMEM); | |
148 | ||
ef209f15 G |
149 | if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) |
150 | goto out; | |
5bc1421e NH |
151 | |
152 | ret = get_prioidx(&cs->prioidx); | |
ef209f15 | 153 | if (ret < 0) { |
e005d193 | 154 | pr_warn("No space in priority index array\n"); |
ef209f15 G |
155 | goto out; |
156 | } | |
157 | ||
158 | ret = update_netdev_tables(); | |
159 | if (ret < 0) { | |
160 | put_prioidx(cs->prioidx); | |
161 | goto out; | |
5bc1421e NH |
162 | } |
163 | ||
164 | return &cs->css; | |
ef209f15 G |
165 | out: |
166 | kfree(cs); | |
167 | return ERR_PTR(ret); | |
5bc1421e NH |
168 | } |
169 | ||
761b3ef5 | 170 | static void cgrp_destroy(struct cgroup *cgrp) |
5bc1421e NH |
171 | { |
172 | struct cgroup_netprio_state *cs; | |
173 | struct net_device *dev; | |
174 | struct netprio_map *map; | |
175 | ||
176 | cs = cgrp_netprio_state(cgrp); | |
177 | rtnl_lock(); | |
178 | for_each_netdev(&init_net, dev) { | |
179 | map = rtnl_dereference(dev->priomap); | |
91c68ce2 | 180 | if (map && cs->prioidx < map->priomap_len) |
5bc1421e NH |
181 | map->priomap[cs->prioidx] = 0; |
182 | } | |
183 | rtnl_unlock(); | |
184 | put_prioidx(cs->prioidx); | |
185 | kfree(cs); | |
186 | } | |
187 | ||
188 | static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft) | |
189 | { | |
190 | return (u64)cgrp_netprio_state(cgrp)->prioidx; | |
191 | } | |
192 | ||
193 | static int read_priomap(struct cgroup *cont, struct cftype *cft, | |
194 | struct cgroup_map_cb *cb) | |
195 | { | |
196 | struct net_device *dev; | |
197 | u32 prioidx = cgrp_netprio_state(cont)->prioidx; | |
198 | u32 priority; | |
199 | struct netprio_map *map; | |
200 | ||
201 | rcu_read_lock(); | |
202 | for_each_netdev_rcu(&init_net, dev) { | |
203 | map = rcu_dereference(dev->priomap); | |
91c68ce2 | 204 | priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0; |
5bc1421e NH |
205 | cb->fill(cb, dev->name, priority); |
206 | } | |
207 | rcu_read_unlock(); | |
208 | return 0; | |
209 | } | |
210 | ||
211 | static int write_priomap(struct cgroup *cgrp, struct cftype *cft, | |
212 | const char *buffer) | |
213 | { | |
214 | char *devname = kstrdup(buffer, GFP_KERNEL); | |
215 | int ret = -EINVAL; | |
216 | u32 prioidx = cgrp_netprio_state(cgrp)->prioidx; | |
217 | unsigned long priority; | |
218 | char *priostr; | |
219 | struct net_device *dev; | |
220 | struct netprio_map *map; | |
221 | ||
222 | if (!devname) | |
223 | return -ENOMEM; | |
224 | ||
225 | /* | |
226 | * Minimally sized valid priomap string | |
227 | */ | |
228 | if (strlen(devname) < 3) | |
229 | goto out_free_devname; | |
230 | ||
231 | priostr = strstr(devname, " "); | |
232 | if (!priostr) | |
233 | goto out_free_devname; | |
234 | ||
235 | /* | |
236 | *Separate the devname from the associated priority | |
237 | *and advance the priostr poitner to the priority value | |
238 | */ | |
239 | *priostr = '\0'; | |
240 | priostr++; | |
241 | ||
242 | /* | |
243 | * If the priostr points to NULL, we're at the end of the passed | |
244 | * in string, and its not a valid write | |
245 | */ | |
246 | if (*priostr == '\0') | |
247 | goto out_free_devname; | |
248 | ||
249 | ret = kstrtoul(priostr, 10, &priority); | |
250 | if (ret < 0) | |
251 | goto out_free_devname; | |
252 | ||
253 | ret = -ENODEV; | |
254 | ||
255 | dev = dev_get_by_name(&init_net, devname); | |
256 | if (!dev) | |
257 | goto out_free_devname; | |
258 | ||
ef209f15 G |
259 | ret = write_update_netdev_table(dev); |
260 | if (ret < 0) | |
261 | goto out_put_dev; | |
262 | ||
5bc1421e NH |
263 | rcu_read_lock(); |
264 | map = rcu_dereference(dev->priomap); | |
265 | if (map) | |
266 | map->priomap[prioidx] = priority; | |
267 | rcu_read_unlock(); | |
ef209f15 G |
268 | |
269 | out_put_dev: | |
5bc1421e NH |
270 | dev_put(dev); |
271 | ||
272 | out_free_devname: | |
273 | kfree(devname); | |
274 | return ret; | |
275 | } | |
276 | ||
406a3c63 JF |
277 | void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) |
278 | { | |
279 | struct task_struct *p; | |
280 | char *tmp = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL); | |
281 | ||
282 | if (!tmp) { | |
283 | pr_warn("Unable to attach cgrp due to alloc failure!\n"); | |
284 | return; | |
285 | } | |
286 | ||
287 | cgroup_taskset_for_each(p, cgrp, tset) { | |
288 | unsigned int fd; | |
289 | struct fdtable *fdt; | |
290 | struct files_struct *files; | |
291 | ||
292 | task_lock(p); | |
293 | files = p->files; | |
294 | if (!files) { | |
295 | task_unlock(p); | |
296 | continue; | |
297 | } | |
298 | ||
299 | rcu_read_lock(); | |
300 | fdt = files_fdtable(files); | |
301 | for (fd = 0; fd < fdt->max_fds; fd++) { | |
302 | char *path; | |
303 | struct file *file; | |
304 | struct socket *sock; | |
305 | unsigned long s; | |
306 | int rv, err = 0; | |
307 | ||
308 | file = fcheck_files(files, fd); | |
309 | if (!file) | |
310 | continue; | |
311 | ||
312 | path = d_path(&file->f_path, tmp, PAGE_SIZE); | |
313 | rv = sscanf(path, "socket:[%lu]", &s); | |
314 | if (rv <= 0) | |
315 | continue; | |
316 | ||
317 | sock = sock_from_file(file, &err); | |
318 | if (!err) | |
319 | sock_update_netprioidx(sock->sk, p); | |
320 | } | |
321 | rcu_read_unlock(); | |
322 | task_unlock(p); | |
323 | } | |
324 | kfree(tmp); | |
325 | } | |
326 | ||
5bc1421e NH |
327 | static struct cftype ss_files[] = { |
328 | { | |
329 | .name = "prioidx", | |
330 | .read_u64 = read_prioidx, | |
331 | }, | |
332 | { | |
333 | .name = "ifpriomap", | |
334 | .read_map = read_priomap, | |
335 | .write_string = write_priomap, | |
336 | }, | |
4baf6e33 | 337 | { } /* terminate */ |
5bc1421e NH |
338 | }; |
339 | ||
676f7c8f TH |
340 | struct cgroup_subsys net_prio_subsys = { |
341 | .name = "net_prio", | |
342 | .create = cgrp_create, | |
343 | .destroy = cgrp_destroy, | |
406a3c63 | 344 | .attach = net_prio_attach, |
676f7c8f TH |
345 | #ifdef CONFIG_NETPRIO_CGROUP |
346 | .subsys_id = net_prio_subsys_id, | |
347 | #endif | |
4baf6e33 | 348 | .base_cftypes = ss_files, |
676f7c8f TH |
349 | .module = THIS_MODULE |
350 | }; | |
5bc1421e NH |
351 | |
352 | static int netprio_device_event(struct notifier_block *unused, | |
353 | unsigned long event, void *ptr) | |
354 | { | |
355 | struct net_device *dev = ptr; | |
356 | struct netprio_map *old; | |
5bc1421e NH |
357 | |
358 | /* | |
359 | * Note this is called with rtnl_lock held so we have update side | |
360 | * protection on our rcu assignments | |
361 | */ | |
362 | ||
363 | switch (event) { | |
5bc1421e NH |
364 | case NETDEV_UNREGISTER: |
365 | old = rtnl_dereference(dev->priomap); | |
2cfa5a04 | 366 | RCU_INIT_POINTER(dev->priomap, NULL); |
5bc1421e NH |
367 | if (old) |
368 | kfree_rcu(old, rcu); | |
369 | break; | |
370 | } | |
371 | return NOTIFY_DONE; | |
372 | } | |
373 | ||
374 | static struct notifier_block netprio_device_notifier = { | |
375 | .notifier_call = netprio_device_event | |
376 | }; | |
377 | ||
378 | static int __init init_cgroup_netprio(void) | |
379 | { | |
380 | int ret; | |
381 | ||
382 | ret = cgroup_load_subsys(&net_prio_subsys); | |
383 | if (ret) | |
384 | goto out; | |
385 | #ifndef CONFIG_NETPRIO_CGROUP | |
386 | smp_wmb(); | |
387 | net_prio_subsys_id = net_prio_subsys.subsys_id; | |
388 | #endif | |
389 | ||
390 | register_netdevice_notifier(&netprio_device_notifier); | |
391 | ||
392 | out: | |
393 | return ret; | |
394 | } | |
395 | ||
396 | static void __exit exit_cgroup_netprio(void) | |
397 | { | |
398 | struct netprio_map *old; | |
399 | struct net_device *dev; | |
400 | ||
401 | unregister_netdevice_notifier(&netprio_device_notifier); | |
402 | ||
403 | cgroup_unload_subsys(&net_prio_subsys); | |
404 | ||
405 | #ifndef CONFIG_NETPRIO_CGROUP | |
406 | net_prio_subsys_id = -1; | |
407 | synchronize_rcu(); | |
408 | #endif | |
409 | ||
410 | rtnl_lock(); | |
411 | for_each_netdev(&init_net, dev) { | |
412 | old = rtnl_dereference(dev->priomap); | |
2cfa5a04 | 413 | RCU_INIT_POINTER(dev->priomap, NULL); |
5bc1421e NH |
414 | if (old) |
415 | kfree_rcu(old, rcu); | |
416 | } | |
417 | rtnl_unlock(); | |
418 | } | |
419 | ||
420 | module_init(init_cgroup_netprio); | |
421 | module_exit(exit_cgroup_netprio); | |
422 | MODULE_LICENSE("GPL v2"); |