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 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 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 28 #define PRIOIDX_SZ 128 29 30 static unsigned long prioidx_map[PRIOIDX_SZ]; 31 static DEFINE_SPINLOCK(prioidx_map_lock); 32 static atomic_t max_prioidx = ATOMIC_INIT(0); 33 34 static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp) 35 { 36 return container_of(cgroup_subsys_state(cgrp, net_prio_subsys_id), 37 struct cgroup_netprio_state, css); 38 } 39 40 static int get_prioidx(u32 *prio) 41 { 42 unsigned long flags; 43 u32 prioidx; 44 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); 49 return -ENOSPC; 50 } 51 set_bit(prioidx, prioidx_map); 52 spin_unlock_irqrestore(&prioidx_map_lock, flags); 53 atomic_set(&max_prioidx, prioidx); 54 *prio = prioidx; 55 return 0; 56 } 57 58 static void put_prioidx(u32 idx) 59 { 60 unsigned long flags; 61 62 spin_lock_irqsave(&prioidx_map_lock, flags); 63 clear_bit(idx, prioidx_map); 64 spin_unlock_irqrestore(&prioidx_map_lock, flags); 65 } 66 67 static void extend_netdev_table(struct net_device *dev, u32 new_len) 68 { 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; 73 int i; 74 75 old_priomap = rtnl_dereference(dev->priomap); 76 77 if (!new_priomap) { 78 pr_warn("Unable to alloc new priomap!\n"); 79 return; 80 } 81 82 for (i = 0; 83 old_priomap && (i < old_priomap->priomap_len); 84 i++) 85 new_priomap->priomap[i] = old_priomap->priomap[i]; 86 87 new_priomap->priomap_len = new_len; 88 89 rcu_assign_pointer(dev->priomap, new_priomap); 90 if (old_priomap) 91 kfree_rcu(old_priomap, rcu); 92 } 93 94 static void update_netdev_tables(void) 95 { 96 struct net_device *dev; 97 u32 max_len = atomic_read(&max_prioidx) + 1; 98 struct netprio_map *map; 99 100 rtnl_lock(); 101 for_each_netdev(&init_net, dev) { 102 map = rtnl_dereference(dev->priomap); 103 if ((!map) || 104 (map->priomap_len < max_len)) 105 extend_netdev_table(dev, max_len); 106 } 107 rtnl_unlock(); 108 } 109 110 static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp) 111 { 112 struct cgroup_netprio_state *cs; 113 int ret; 114 115 cs = kzalloc(sizeof(*cs), GFP_KERNEL); 116 if (!cs) 117 return ERR_PTR(-ENOMEM); 118 119 if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx) { 120 kfree(cs); 121 return ERR_PTR(-EINVAL); 122 } 123 124 ret = get_prioidx(&cs->prioidx); 125 if (ret != 0) { 126 pr_warn("No space in priority index array\n"); 127 kfree(cs); 128 return ERR_PTR(ret); 129 } 130 131 return &cs->css; 132 } 133 134 static void cgrp_destroy(struct cgroup *cgrp) 135 { 136 struct cgroup_netprio_state *cs; 137 struct net_device *dev; 138 struct netprio_map *map; 139 140 cs = cgrp_netprio_state(cgrp); 141 rtnl_lock(); 142 for_each_netdev(&init_net, dev) { 143 map = rtnl_dereference(dev->priomap); 144 if (map) 145 map->priomap[cs->prioidx] = 0; 146 } 147 rtnl_unlock(); 148 put_prioidx(cs->prioidx); 149 kfree(cs); 150 } 151 152 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft) 153 { 154 return (u64)cgrp_netprio_state(cgrp)->prioidx; 155 } 156 157 static int read_priomap(struct cgroup *cont, struct cftype *cft, 158 struct cgroup_map_cb *cb) 159 { 160 struct net_device *dev; 161 u32 prioidx = cgrp_netprio_state(cont)->prioidx; 162 u32 priority; 163 struct netprio_map *map; 164 165 rcu_read_lock(); 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); 170 } 171 rcu_read_unlock(); 172 return 0; 173 } 174 175 static int write_priomap(struct cgroup *cgrp, struct cftype *cft, 176 const char *buffer) 177 { 178 char *devname = kstrdup(buffer, GFP_KERNEL); 179 int ret = -EINVAL; 180 u32 prioidx = cgrp_netprio_state(cgrp)->prioidx; 181 unsigned long priority; 182 char *priostr; 183 struct net_device *dev; 184 struct netprio_map *map; 185 186 if (!devname) 187 return -ENOMEM; 188 189 /* 190 * Minimally sized valid priomap string 191 */ 192 if (strlen(devname) < 3) 193 goto out_free_devname; 194 195 priostr = strstr(devname, " "); 196 if (!priostr) 197 goto out_free_devname; 198 199 /* 200 *Separate the devname from the associated priority 201 *and advance the priostr poitner to the priority value 202 */ 203 *priostr = '\0'; 204 priostr++; 205 206 /* 207 * If the priostr points to NULL, we're at the end of the passed 208 * in string, and its not a valid write 209 */ 210 if (*priostr == '\0') 211 goto out_free_devname; 212 213 ret = kstrtoul(priostr, 10, &priority); 214 if (ret < 0) 215 goto out_free_devname; 216 217 ret = -ENODEV; 218 219 dev = dev_get_by_name(&init_net, devname); 220 if (!dev) 221 goto out_free_devname; 222 223 update_netdev_tables(); 224 ret = 0; 225 rcu_read_lock(); 226 map = rcu_dereference(dev->priomap); 227 if (map) 228 map->priomap[prioidx] = priority; 229 rcu_read_unlock(); 230 dev_put(dev); 231 232 out_free_devname: 233 kfree(devname); 234 return ret; 235 } 236 237 static struct cftype ss_files[] = { 238 { 239 .name = "prioidx", 240 .read_u64 = read_prioidx, 241 }, 242 { 243 .name = "ifpriomap", 244 .read_map = read_priomap, 245 .write_string = write_priomap, 246 }, 247 { } /* terminate */ 248 }; 249 250 struct cgroup_subsys net_prio_subsys = { 251 .name = "net_prio", 252 .create = cgrp_create, 253 .destroy = cgrp_destroy, 254 #ifdef CONFIG_NETPRIO_CGROUP 255 .subsys_id = net_prio_subsys_id, 256 #endif 257 .base_cftypes = ss_files, 258 .module = THIS_MODULE 259 }; 260 261 static int netprio_device_event(struct notifier_block *unused, 262 unsigned long event, void *ptr) 263 { 264 struct net_device *dev = ptr; 265 struct netprio_map *old; 266 267 /* 268 * Note this is called with rtnl_lock held so we have update side 269 * protection on our rcu assignments 270 */ 271 272 switch (event) { 273 case NETDEV_UNREGISTER: 274 old = rtnl_dereference(dev->priomap); 275 RCU_INIT_POINTER(dev->priomap, NULL); 276 if (old) 277 kfree_rcu(old, rcu); 278 break; 279 } 280 return NOTIFY_DONE; 281 } 282 283 static struct notifier_block netprio_device_notifier = { 284 .notifier_call = netprio_device_event 285 }; 286 287 static int __init init_cgroup_netprio(void) 288 { 289 int ret; 290 291 ret = cgroup_load_subsys(&net_prio_subsys); 292 if (ret) 293 goto out; 294 #ifndef CONFIG_NETPRIO_CGROUP 295 smp_wmb(); 296 net_prio_subsys_id = net_prio_subsys.subsys_id; 297 #endif 298 299 register_netdevice_notifier(&netprio_device_notifier); 300 301 out: 302 return ret; 303 } 304 305 static void __exit exit_cgroup_netprio(void) 306 { 307 struct netprio_map *old; 308 struct net_device *dev; 309 310 unregister_netdevice_notifier(&netprio_device_notifier); 311 312 cgroup_unload_subsys(&net_prio_subsys); 313 314 #ifndef CONFIG_NETPRIO_CGROUP 315 net_prio_subsys_id = -1; 316 synchronize_rcu(); 317 #endif 318 319 rtnl_lock(); 320 for_each_netdev(&init_net, dev) { 321 old = rtnl_dereference(dev->priomap); 322 RCU_INIT_POINTER(dev->priomap, NULL); 323 if (old) 324 kfree_rcu(old, rcu); 325 } 326 rtnl_unlock(); 327 } 328 329 module_init(init_cgroup_netprio); 330 module_exit(exit_cgroup_netprio); 331 MODULE_LICENSE("GPL v2"); 332