2 * net/core/netprio_cgroup.c Priority Control Group
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.
9 * Authors: Neil Horman <nhorman@tuxdriver.com>
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
26 #include <net/netprio_cgroup.h>
28 #include <linux/fdtable.h>
30 #define PRIOMAP_MIN_SZ 128
32 static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
34 return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
35 struct cgroup_netprio_state, css);
39 * Extend @dev->priomap so that it's large enough to accomodate
40 * @target_idx. @dev->priomap.priomap_len > @target_idx after successful
41 * return. Must be called under rtnl lock.
43 static int extend_netdev_table(struct net_device *dev, u32 target_idx)
45 struct netprio_map *old, *new;
46 size_t new_sz, new_len;
48 /* is the existing priomap large enough? */
49 old = rtnl_dereference(dev->priomap);
50 if (old && old->priomap_len > target_idx)
54 * Determine the new size. Let's keep it power-of-two. We start
55 * from PRIOMAP_MIN_SZ and double it until it's large enough to
56 * accommodate @target_idx.
58 new_sz = PRIOMAP_MIN_SZ;
60 new_len = (new_sz - offsetof(struct netprio_map, priomap)) /
61 sizeof(new->priomap[0]);
62 if (new_len > target_idx)
66 if (WARN_ON(new_sz < PRIOMAP_MIN_SZ))
71 new = kzalloc(new_sz, GFP_KERNEL);
73 pr_warn("Unable to alloc new priomap!\n");
78 memcpy(new->priomap, old->priomap,
79 old->priomap_len * sizeof(old->priomap[0]));
81 new->priomap_len = new_len;
83 /* install the new priomap */
84 rcu_assign_pointer(dev->priomap, new);
91 * netprio_prio - return the effective netprio of a cgroup-net_device pair
92 * @cgrp: cgroup part of the target pair
93 * @dev: net_device part of the target pair
95 * Should be called under RCU read or rtnl lock.
97 static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev)
99 struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
101 if (map && cgrp->id < map->priomap_len)
102 return map->priomap[cgrp->id];
107 * netprio_set_prio - set netprio on a cgroup-net_device pair
108 * @cgrp: cgroup part of the target pair
109 * @dev: net_device part of the target pair
112 * Set netprio to @prio on @cgrp-@dev pair. Should be called under rtnl
113 * lock and may fail under memory pressure for non-zero @prio.
115 static int netprio_set_prio(struct cgroup *cgrp, struct net_device *dev,
118 struct netprio_map *map;
121 /* avoid extending priomap for zero writes */
122 map = rtnl_dereference(dev->priomap);
123 if (!prio && (!map || map->priomap_len <= cgrp->id))
126 ret = extend_netdev_table(dev, cgrp->id);
130 map = rtnl_dereference(dev->priomap);
131 map->priomap[cgrp->id] = prio;
135 static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp)
137 struct cgroup_netprio_state *cs;
139 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
141 return ERR_PTR(-ENOMEM);
146 static int cgrp_css_online(struct cgroup *cgrp)
148 struct cgroup *parent = cgrp->parent;
149 struct net_device *dev;
157 * Inherit prios from the parent. As all prios are set during
158 * onlining, there is no need to clear them on offline.
160 for_each_netdev(&init_net, dev) {
161 u32 prio = netprio_prio(parent, dev);
163 ret = netprio_set_prio(cgrp, dev, prio);
171 static void cgrp_css_free(struct cgroup *cgrp)
173 kfree(cgrp_netprio_state(cgrp));
176 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
181 static int read_priomap(struct cgroup *cont, struct cftype *cft,
182 struct cgroup_map_cb *cb)
184 struct net_device *dev;
187 for_each_netdev_rcu(&init_net, dev)
188 cb->fill(cb, dev->name, netprio_prio(cont, dev));
193 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
196 char devname[IFNAMSIZ + 1];
197 struct net_device *dev;
201 if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
204 dev = dev_get_by_name(&init_net, devname);
210 ret = netprio_set_prio(cgrp, dev, prio);
217 static int update_netprio(const void *v, struct file *file, unsigned n)
220 struct socket *sock = sock_from_file(file, &err);
222 sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v;
226 static void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
228 struct task_struct *p;
231 cgroup_taskset_for_each(p, cgrp, tset) {
233 v = (void *)(unsigned long)task_netprioidx(p);
234 iterate_fd(p->files, 0, update_netprio, v);
239 static struct cftype ss_files[] = {
242 .read_u64 = read_prioidx,
246 .read_map = read_priomap,
247 .write_string = write_priomap,
252 struct cgroup_subsys net_prio_subsys = {
254 .css_alloc = cgrp_css_alloc,
255 .css_online = cgrp_css_online,
256 .css_free = cgrp_css_free,
257 .attach = net_prio_attach,
258 .subsys_id = net_prio_subsys_id,
259 .base_cftypes = ss_files,
260 .module = THIS_MODULE,
263 static int netprio_device_event(struct notifier_block *unused,
264 unsigned long event, void *ptr)
266 struct net_device *dev = ptr;
267 struct netprio_map *old;
270 * Note this is called with rtnl_lock held so we have update side
271 * protection on our rcu assignments
275 case NETDEV_UNREGISTER:
276 old = rtnl_dereference(dev->priomap);
277 RCU_INIT_POINTER(dev->priomap, NULL);
285 static struct notifier_block netprio_device_notifier = {
286 .notifier_call = netprio_device_event
289 static int __init init_cgroup_netprio(void)
293 ret = cgroup_load_subsys(&net_prio_subsys);
297 register_netdevice_notifier(&netprio_device_notifier);
303 static void __exit exit_cgroup_netprio(void)
305 struct netprio_map *old;
306 struct net_device *dev;
308 unregister_netdevice_notifier(&netprio_device_notifier);
310 cgroup_unload_subsys(&net_prio_subsys);
313 for_each_netdev(&init_net, dev) {
314 old = rtnl_dereference(dev->priomap);
315 RCU_INIT_POINTER(dev->priomap, NULL);
322 module_init(init_cgroup_netprio);
323 module_exit(exit_cgroup_netprio);
324 MODULE_LICENSE("GPL v2");