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 #define PRIOIDX_SZ 128
30 static unsigned long prioidx_map[PRIOIDX_SZ];
31 static DEFINE_SPINLOCK(prioidx_map_lock);
32 static atomic_t max_prioidx = ATOMIC_INIT(0);
34 static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp)
36 return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id),
37 struct cgroup_netprio_state, css);
40 static int get_prioidx(u32 *prio)
45 spin_lock_irqsave(&prioidx_map_lock, flags);
46 prioidx = find_first_zero_bit(prioidx_map, sizeof(unsigned long) * PRIOIDX_SZ);
47 if (prioidx == sizeof(unsigned long) * PRIOIDX_SZ) {
48 spin_unlock_irqrestore(&prioidx_map_lock, flags);
51 set_bit(prioidx, prioidx_map);
52 spin_unlock_irqrestore(&prioidx_map_lock, flags);
53 atomic_set(&max_prioidx, prioidx);
58 static void put_prioidx(u32 idx)
62 spin_lock_irqsave(&prioidx_map_lock, flags);
63 clear_bit(idx, prioidx_map);
64 spin_unlock_irqrestore(&prioidx_map_lock, flags);
67 static void extend_netdev_table(struct net_device *dev, u32 new_len)
69 size_t new_size = sizeof(struct netprio_map) +
70 ((sizeof(u32) * new_len));
71 struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
72 struct netprio_map *old_priomap;
75 old_priomap = rtnl_dereference(dev->priomap);
78 pr_warn("Unable to alloc new priomap!\n");
83 old_priomap && (i < old_priomap->priomap_len);
85 new_priomap->priomap[i] = old_priomap->priomap[i];
87 new_priomap->priomap_len = new_len;
89 rcu_assign_pointer(dev->priomap, new_priomap);
91 kfree_rcu(old_priomap, rcu);
94 static void update_netdev_tables(void)
96 struct net_device *dev;
97 u32 max_len = atomic_read(&max_prioidx) + 1;
98 struct netprio_map *map;
101 for_each_netdev(&init_net, dev) {
102 map = rtnl_dereference(dev->priomap);
104 (map->priomap_len < max_len))
105 extend_netdev_table(dev, max_len);
110 static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
112 struct cgroup_netprio_state *cs;
115 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
117 return ERR_PTR(-ENOMEM);
119 if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) {
121 return ERR_PTR(-EINVAL);
124 ret = get_prioidx(&cs->prioidx);
126 pr_warn("No space in priority index array\n");
134 static void cgrp_destroy(struct cgroup *cgrp)
136 struct cgroup_netprio_state *cs;
137 struct net_device *dev;
138 struct netprio_map *map;
140 cs = cgrp_netprio_state(cgrp);
142 for_each_netdev(&init_net, dev) {
143 map = rtnl_dereference(dev->priomap);
145 map->priomap[cs->prioidx] = 0;
148 put_prioidx(cs->prioidx);
152 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
154 return (u64)cgrp_netprio_state(cgrp)->prioidx;
157 static int read_priomap(struct cgroup *cont, struct cftype *cft,
158 struct cgroup_map_cb *cb)
160 struct net_device *dev;
161 u32 prioidx = cgrp_netprio_state(cont)->prioidx;
163 struct netprio_map *map;
166 for_each_netdev_rcu(&init_net, dev) {
167 map = rcu_dereference(dev->priomap);
168 priority = map ? map->priomap[prioidx] : 0;
169 cb->fill(cb, dev->name, priority);
175 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
178 char *devname = kstrdup(buffer, GFP_KERNEL);
180 u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
181 unsigned long priority;
183 struct net_device *dev;
184 struct netprio_map *map;
190 * Minimally sized valid priomap string
192 if (strlen(devname) < 3)
193 goto out_free_devname;
195 priostr = strstr(devname, " ");
197 goto out_free_devname;
200 *Separate the devname from the associated priority
201 *and advance the priostr poitner to the priority value
207 * If the priostr points to NULL, we're at the end of the passed
208 * in string, and its not a valid write
210 if (*priostr == '\0')
211 goto out_free_devname;
213 ret = kstrtoul(priostr, 10, &priority);
215 goto out_free_devname;
219 dev = dev_get_by_name(&init_net, devname);
221 goto out_free_devname;
223 update_netdev_tables();
226 map = rcu_dereference(dev->priomap);
228 map->priomap[prioidx] = priority;
237 static struct cftype ss_files[] = {
240 .read_u64 = read_prioidx,
244 .read_map = read_priomap,
245 .write_string = write_priomap,
250 struct cgroup_subsys net_prio_subsys = {
252 .create = cgrp_create,
253 .destroy = cgrp_destroy,
254 #ifdef CONFIG_NETPRIO_CGROUP
255 .subsys_id = net_prio_subsys_id,
257 .base_cftypes = ss_files,
258 .module = THIS_MODULE
261 static int netprio_device_event(struct notifier_block *unused,
262 unsigned long event, void *ptr)
264 struct net_device *dev = ptr;
265 struct netprio_map *old;
268 * Note this is called with rtnl_lock held so we have update side
269 * protection on our rcu assignments
273 case NETDEV_UNREGISTER:
274 old = rtnl_dereference(dev->priomap);
275 RCU_INIT_POINTER(dev->priomap, NULL);
283 static struct notifier_block netprio_device_notifier = {
284 .notifier_call = netprio_device_event
287 static int __init init_cgroup_netprio(void)
291 ret = cgroup_load_subsys(&net_prio_subsys);
294 #ifndef CONFIG_NETPRIO_CGROUP
296 net_prio_subsys_id = net_prio_subsys.subsys_id;
299 register_netdevice_notifier(&netprio_device_notifier);
305 static void __exit exit_cgroup_netprio(void)
307 struct netprio_map *old;
308 struct net_device *dev;
310 unregister_netdevice_notifier(&netprio_device_notifier);
312 cgroup_unload_subsys(&net_prio_subsys);
314 #ifndef CONFIG_NETPRIO_CGROUP
315 net_prio_subsys_id = -1;
320 for_each_netdev(&init_net, dev) {
321 old = rtnl_dereference(dev->priomap);
322 RCU_INIT_POINTER(dev->priomap, NULL);
329 module_init(init_cgroup_netprio);
330 module_exit(exit_cgroup_netprio);
331 MODULE_LICENSE("GPL v2");