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 PRIOIDX_SZ 128
32 static unsigned long prioidx_map[PRIOIDX_SZ];
33 static DEFINE_SPINLOCK(prioidx_map_lock);
34 static atomic_t max_prioidx = ATOMIC_INIT(0);
36 static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
38 return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
39 struct cgroup_netprio_state, css);
42 static int get_prioidx(u32 *prio)
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);
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);
61 static void put_prioidx(u32 idx)
65 spin_lock_irqsave(&prioidx_map_lock, flags);
66 clear_bit(idx, prioidx_map);
67 spin_unlock_irqrestore(&prioidx_map_lock, flags);
70 static int extend_netdev_table(struct net_device *dev, u32 new_len)
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;
77 old_priomap = rtnl_dereference(dev->priomap);
80 pr_warn("Unable to alloc new priomap!\n");
85 memcpy(new_priomap->priomap, old_priomap->priomap,
86 old_priomap->priomap_len *
87 sizeof(old_priomap->priomap[0]));
89 new_priomap->priomap_len = new_len;
91 rcu_assign_pointer(dev->priomap, new_priomap);
93 kfree_rcu(old_priomap, rcu);
97 static int write_update_netdev_table(struct net_device *dev)
101 struct netprio_map *map;
103 max_len = atomic_read(&max_prioidx) + 1;
104 map = rtnl_dereference(dev->priomap);
105 if (!map || map->priomap_len < max_len)
106 ret = extend_netdev_table(dev, max_len);
111 static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
113 struct cgroup_netprio_state *cs;
116 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
118 return ERR_PTR(-ENOMEM);
120 if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx)
123 ret = get_prioidx(&cs->prioidx);
125 pr_warn("No space in priority index array\n");
135 static void cgrp_destroy(struct cgroup *cgrp)
137 struct cgroup_netprio_state *cs;
138 struct net_device *dev;
139 struct netprio_map *map;
141 cs = cgrp_netprio_state(cgrp);
143 for_each_netdev(&init_net, dev) {
144 map = rtnl_dereference(dev->priomap);
145 if (map && cs->prioidx < map->priomap_len)
146 map->priomap[cs->prioidx] = 0;
149 put_prioidx(cs->prioidx);
153 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
155 return (u64)cgrp_netprio_state(cgrp)->prioidx;
158 static int read_priomap(struct cgroup *cont, struct cftype *cft,
159 struct cgroup_map_cb *cb)
161 struct net_device *dev;
162 u32 prioidx = cgrp_netprio_state(cont)->prioidx;
164 struct netprio_map *map;
167 for_each_netdev_rcu(&init_net, dev) {
168 map = rcu_dereference(dev->priomap);
169 priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;
170 cb->fill(cb, dev->name, priority);
176 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
179 char *devname = kstrdup(buffer, GFP_KERNEL);
181 u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
182 unsigned long priority;
184 struct net_device *dev;
185 struct netprio_map *map;
191 * Minimally sized valid priomap string
193 if (strlen(devname) < 3)
194 goto out_free_devname;
196 priostr = strstr(devname, " ");
198 goto out_free_devname;
201 *Separate the devname from the associated priority
202 *and advance the priostr pointer to the priority value
208 * If the priostr points to NULL, we're at the end of the passed
209 * in string, and its not a valid write
211 if (*priostr == '\0')
212 goto out_free_devname;
214 ret = kstrtoul(priostr, 10, &priority);
216 goto out_free_devname;
220 dev = dev_get_by_name(&init_net, devname);
222 goto out_free_devname;
225 ret = write_update_netdev_table(dev);
229 map = rtnl_dereference(dev->priomap);
231 map->priomap[prioidx] = priority;
242 static int update_netprio(const void *v, struct file *file, unsigned n)
245 struct socket *sock = sock_from_file(file, &err);
247 sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v;
251 static void net_prio_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
253 struct task_struct *p;
256 cgroup_taskset_for_each(p, cgrp, tset) {
258 v = (void *)(unsigned long)task_netprioidx(p);
259 iterate_fd(p->files, 0, update_netprio, v);
264 static struct cftype ss_files[] = {
267 .read_u64 = read_prioidx,
271 .read_map = read_priomap,
272 .write_string = write_priomap,
277 struct cgroup_subsys net_prio_subsys = {
279 .create = cgrp_create,
280 .destroy = cgrp_destroy,
281 .attach = net_prio_attach,
282 .subsys_id = net_prio_subsys_id,
283 .base_cftypes = ss_files,
284 .module = THIS_MODULE,
287 * net_prio has artificial limit on the number of cgroups and
288 * disallows nesting making it impossible to co-mount it with other
289 * hierarchical subsystems. Remove the artificially low PRIOIDX_SZ
290 * limit and properly nest configuration such that children follow
291 * their parents' configurations by default and are allowed to
292 * override and remove the following.
294 .broken_hierarchy = true,
297 static int netprio_device_event(struct notifier_block *unused,
298 unsigned long event, void *ptr)
300 struct net_device *dev = ptr;
301 struct netprio_map *old;
304 * Note this is called with rtnl_lock held so we have update side
305 * protection on our rcu assignments
309 case NETDEV_UNREGISTER:
310 old = rtnl_dereference(dev->priomap);
311 RCU_INIT_POINTER(dev->priomap, NULL);
319 static struct notifier_block netprio_device_notifier = {
320 .notifier_call = netprio_device_event
323 static int __init init_cgroup_netprio(void)
327 ret = cgroup_load_subsys(&net_prio_subsys);
331 register_netdevice_notifier(&netprio_device_notifier);
337 static void __exit exit_cgroup_netprio(void)
339 struct netprio_map *old;
340 struct net_device *dev;
342 unregister_netdevice_notifier(&netprio_device_notifier);
344 cgroup_unload_subsys(&net_prio_subsys);
347 for_each_netdev(&init_net, dev) {
348 old = rtnl_dereference(dev->priomap);
349 RCU_INIT_POINTER(dev->priomap, NULL);
356 module_init(init_cgroup_netprio);
357 module_exit(exit_cgroup_netprio);
358 MODULE_LICENSE("GPL v2");