Commit | Line | Data |
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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 | ||
4a6ee25c | 30 | #define PRIOMAP_MIN_SZ 128 |
5bc1421e | 31 | |
4a6ee25c TH |
32 | /* |
33 | * Extend @dev->priomap so that it's large enough to accomodate | |
34 | * @target_idx. @dev->priomap.priomap_len > @target_idx after successful | |
35 | * return. Must be called under rtnl lock. | |
36 | */ | |
37 | static int extend_netdev_table(struct net_device *dev, u32 target_idx) | |
5bc1421e | 38 | { |
4a6ee25c TH |
39 | struct netprio_map *old, *new; |
40 | size_t new_sz, new_len; | |
5bc1421e | 41 | |
4a6ee25c | 42 | /* is the existing priomap large enough? */ |
52bca930 | 43 | old = rtnl_dereference(dev->priomap); |
4a6ee25c TH |
44 | if (old && old->priomap_len > target_idx) |
45 | return 0; | |
46 | ||
47 | /* | |
48 | * Determine the new size. Let's keep it power-of-two. We start | |
49 | * from PRIOMAP_MIN_SZ and double it until it's large enough to | |
50 | * accommodate @target_idx. | |
51 | */ | |
52 | new_sz = PRIOMAP_MIN_SZ; | |
53 | while (true) { | |
54 | new_len = (new_sz - offsetof(struct netprio_map, priomap)) / | |
55 | sizeof(new->priomap[0]); | |
56 | if (new_len > target_idx) | |
57 | break; | |
58 | new_sz *= 2; | |
59 | /* overflowed? */ | |
60 | if (WARN_ON(new_sz < PRIOMAP_MIN_SZ)) | |
61 | return -ENOSPC; | |
62 | } | |
5bc1421e | 63 | |
4a6ee25c TH |
64 | /* allocate & copy */ |
65 | new = kzalloc(new_sz, GFP_KERNEL); | |
62b5942a | 66 | if (!new) |
ef209f15 | 67 | return -ENOMEM; |
5bc1421e | 68 | |
52bca930 TH |
69 | if (old) |
70 | memcpy(new->priomap, old->priomap, | |
71 | old->priomap_len * sizeof(old->priomap[0])); | |
5bc1421e | 72 | |
52bca930 | 73 | new->priomap_len = new_len; |
5bc1421e | 74 | |
4a6ee25c | 75 | /* install the new priomap */ |
52bca930 TH |
76 | rcu_assign_pointer(dev->priomap, new); |
77 | if (old) | |
78 | kfree_rcu(old, rcu); | |
ef209f15 G |
79 | return 0; |
80 | } | |
81 | ||
666b0ebe TH |
82 | /** |
83 | * netprio_prio - return the effective netprio of a cgroup-net_device pair | |
6d37b974 | 84 | * @css: css part of the target pair |
666b0ebe TH |
85 | * @dev: net_device part of the target pair |
86 | * | |
87 | * Should be called under RCU read or rtnl lock. | |
88 | */ | |
6d37b974 | 89 | static u32 netprio_prio(struct cgroup_subsys_state *css, struct net_device *dev) |
666b0ebe TH |
90 | { |
91 | struct netprio_map *map = rcu_dereference_rtnl(dev->priomap); | |
6d37b974 | 92 | int id = css->cgroup->id; |
666b0ebe | 93 | |
6d37b974 TH |
94 | if (map && id < map->priomap_len) |
95 | return map->priomap[id]; | |
666b0ebe TH |
96 | return 0; |
97 | } | |
98 | ||
99 | /** | |
100 | * netprio_set_prio - set netprio on a cgroup-net_device pair | |
6d37b974 | 101 | * @css: css part of the target pair |
666b0ebe TH |
102 | * @dev: net_device part of the target pair |
103 | * @prio: prio to set | |
104 | * | |
6d37b974 | 105 | * Set netprio to @prio on @css-@dev pair. Should be called under rtnl |
666b0ebe TH |
106 | * lock and may fail under memory pressure for non-zero @prio. |
107 | */ | |
6d37b974 TH |
108 | static int netprio_set_prio(struct cgroup_subsys_state *css, |
109 | struct net_device *dev, u32 prio) | |
666b0ebe TH |
110 | { |
111 | struct netprio_map *map; | |
6d37b974 | 112 | int id = css->cgroup->id; |
666b0ebe TH |
113 | int ret; |
114 | ||
115 | /* avoid extending priomap for zero writes */ | |
116 | map = rtnl_dereference(dev->priomap); | |
6d37b974 | 117 | if (!prio && (!map || map->priomap_len <= id)) |
666b0ebe TH |
118 | return 0; |
119 | ||
6d37b974 | 120 | ret = extend_netdev_table(dev, id); |
666b0ebe TH |
121 | if (ret) |
122 | return ret; | |
123 | ||
124 | map = rtnl_dereference(dev->priomap); | |
6d37b974 | 125 | map->priomap[id] = prio; |
666b0ebe TH |
126 | return 0; |
127 | } | |
128 | ||
eb95419b TH |
129 | static struct cgroup_subsys_state * |
130 | cgrp_css_alloc(struct cgroup_subsys_state *parent_css) | |
5bc1421e | 131 | { |
6d37b974 | 132 | struct cgroup_subsys_state *css; |
88d642fa | 133 | |
6d37b974 TH |
134 | css = kzalloc(sizeof(*css), GFP_KERNEL); |
135 | if (!css) | |
5bc1421e NH |
136 | return ERR_PTR(-ENOMEM); |
137 | ||
6d37b974 | 138 | return css; |
5bc1421e NH |
139 | } |
140 | ||
eb95419b | 141 | static int cgrp_css_online(struct cgroup_subsys_state *css) |
5bc1421e | 142 | { |
eb95419b | 143 | struct cgroup_subsys_state *parent_css = css_parent(css); |
5bc1421e | 144 | struct net_device *dev; |
811d8d6f TH |
145 | int ret = 0; |
146 | ||
eb95419b | 147 | if (!parent_css) |
811d8d6f | 148 | return 0; |
5bc1421e | 149 | |
5bc1421e | 150 | rtnl_lock(); |
811d8d6f TH |
151 | /* |
152 | * Inherit prios from the parent. As all prios are set during | |
153 | * onlining, there is no need to clear them on offline. | |
154 | */ | |
155 | for_each_netdev(&init_net, dev) { | |
6d37b974 | 156 | u32 prio = netprio_prio(parent_css, dev); |
811d8d6f | 157 | |
6d37b974 | 158 | ret = netprio_set_prio(css, dev, prio); |
811d8d6f TH |
159 | if (ret) |
160 | break; | |
161 | } | |
5bc1421e | 162 | rtnl_unlock(); |
811d8d6f TH |
163 | return ret; |
164 | } | |
165 | ||
eb95419b | 166 | static void cgrp_css_free(struct cgroup_subsys_state *css) |
811d8d6f | 167 | { |
eb95419b | 168 | kfree(css); |
5bc1421e NH |
169 | } |
170 | ||
182446d0 | 171 | static u64 read_prioidx(struct cgroup_subsys_state *css, struct cftype *cft) |
5bc1421e | 172 | { |
182446d0 | 173 | return css->cgroup->id; |
5bc1421e NH |
174 | } |
175 | ||
182446d0 | 176 | static int read_priomap(struct cgroup_subsys_state *css, struct cftype *cft, |
5bc1421e NH |
177 | struct cgroup_map_cb *cb) |
178 | { | |
179 | struct net_device *dev; | |
5bc1421e NH |
180 | |
181 | rcu_read_lock(); | |
666b0ebe | 182 | for_each_netdev_rcu(&init_net, dev) |
6d37b974 | 183 | cb->fill(cb, dev->name, netprio_prio(css, dev)); |
5bc1421e NH |
184 | rcu_read_unlock(); |
185 | return 0; | |
186 | } | |
187 | ||
182446d0 | 188 | static int write_priomap(struct cgroup_subsys_state *css, struct cftype *cft, |
5bc1421e NH |
189 | const char *buffer) |
190 | { | |
6d5759dd | 191 | char devname[IFNAMSIZ + 1]; |
5bc1421e | 192 | struct net_device *dev; |
6d5759dd TH |
193 | u32 prio; |
194 | int ret; | |
5bc1421e | 195 | |
6d5759dd TH |
196 | if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2) |
197 | return -EINVAL; | |
5bc1421e NH |
198 | |
199 | dev = dev_get_by_name(&init_net, devname); | |
200 | if (!dev) | |
6d5759dd | 201 | return -ENODEV; |
5bc1421e | 202 | |
476ad154 | 203 | rtnl_lock(); |
6d5759dd | 204 | |
6d37b974 | 205 | ret = netprio_set_prio(css, dev, prio); |
ef209f15 | 206 | |
476ad154 | 207 | rtnl_unlock(); |
5bc1421e | 208 | dev_put(dev); |
5bc1421e NH |
209 | return ret; |
210 | } | |
211 | ||
c3c073f8 AV |
212 | static int update_netprio(const void *v, struct file *file, unsigned n) |
213 | { | |
214 | int err; | |
215 | struct socket *sock = sock_from_file(file, &err); | |
216 | if (sock) | |
217 | sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v; | |
218 | return 0; | |
219 | } | |
220 | ||
eb95419b TH |
221 | static void net_prio_attach(struct cgroup_subsys_state *css, |
222 | struct cgroup_taskset *tset) | |
406a3c63 JF |
223 | { |
224 | struct task_struct *p; | |
c3c073f8 | 225 | void *v; |
406a3c63 | 226 | |
d99c8727 | 227 | cgroup_taskset_for_each(p, css, tset) { |
406a3c63 | 228 | task_lock(p); |
c3c073f8 AV |
229 | v = (void *)(unsigned long)task_netprioidx(p); |
230 | iterate_fd(p->files, 0, update_netprio, v); | |
406a3c63 JF |
231 | task_unlock(p); |
232 | } | |
406a3c63 JF |
233 | } |
234 | ||
5bc1421e NH |
235 | static struct cftype ss_files[] = { |
236 | { | |
237 | .name = "prioidx", | |
238 | .read_u64 = read_prioidx, | |
239 | }, | |
240 | { | |
241 | .name = "ifpriomap", | |
242 | .read_map = read_priomap, | |
243 | .write_string = write_priomap, | |
244 | }, | |
4baf6e33 | 245 | { } /* terminate */ |
5bc1421e NH |
246 | }; |
247 | ||
676f7c8f TH |
248 | struct cgroup_subsys net_prio_subsys = { |
249 | .name = "net_prio", | |
92fb9748 | 250 | .css_alloc = cgrp_css_alloc, |
811d8d6f | 251 | .css_online = cgrp_css_online, |
92fb9748 | 252 | .css_free = cgrp_css_free, |
406a3c63 | 253 | .attach = net_prio_attach, |
676f7c8f | 254 | .subsys_id = net_prio_subsys_id, |
4baf6e33 | 255 | .base_cftypes = ss_files, |
8c7f6edb | 256 | .module = THIS_MODULE, |
676f7c8f | 257 | }; |
5bc1421e NH |
258 | |
259 | static int netprio_device_event(struct notifier_block *unused, | |
260 | unsigned long event, void *ptr) | |
261 | { | |
351638e7 | 262 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
5bc1421e | 263 | struct netprio_map *old; |
5bc1421e NH |
264 | |
265 | /* | |
266 | * Note this is called with rtnl_lock held so we have update side | |
267 | * protection on our rcu assignments | |
268 | */ | |
269 | ||
270 | switch (event) { | |
5bc1421e NH |
271 | case NETDEV_UNREGISTER: |
272 | old = rtnl_dereference(dev->priomap); | |
2cfa5a04 | 273 | RCU_INIT_POINTER(dev->priomap, NULL); |
5bc1421e NH |
274 | if (old) |
275 | kfree_rcu(old, rcu); | |
276 | break; | |
277 | } | |
278 | return NOTIFY_DONE; | |
279 | } | |
280 | ||
281 | static struct notifier_block netprio_device_notifier = { | |
282 | .notifier_call = netprio_device_event | |
283 | }; | |
284 | ||
285 | static int __init init_cgroup_netprio(void) | |
286 | { | |
287 | int ret; | |
288 | ||
289 | ret = cgroup_load_subsys(&net_prio_subsys); | |
290 | if (ret) | |
291 | goto out; | |
5bc1421e NH |
292 | |
293 | register_netdevice_notifier(&netprio_device_notifier); | |
294 | ||
295 | out: | |
296 | return ret; | |
297 | } | |
298 | ||
299 | static void __exit exit_cgroup_netprio(void) | |
300 | { | |
301 | struct netprio_map *old; | |
302 | struct net_device *dev; | |
303 | ||
304 | unregister_netdevice_notifier(&netprio_device_notifier); | |
305 | ||
306 | cgroup_unload_subsys(&net_prio_subsys); | |
307 | ||
5bc1421e NH |
308 | rtnl_lock(); |
309 | for_each_netdev(&init_net, dev) { | |
310 | old = rtnl_dereference(dev->priomap); | |
2cfa5a04 | 311 | RCU_INIT_POINTER(dev->priomap, NULL); |
5bc1421e NH |
312 | if (old) |
313 | kfree_rcu(old, rcu); | |
314 | } | |
315 | rtnl_unlock(); | |
316 | } | |
317 | ||
318 | module_init(init_cgroup_netprio); | |
319 | module_exit(exit_cgroup_netprio); | |
320 | MODULE_LICENSE("GPL v2"); |