Pileus Git - ~andy/linux/blob - net/core/netprio_cgroup.c

   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         if (atomic_read(&max_prioidx) < prioidx)
  53                 atomic_set(&max_prioidx, prioidx);
  54         spin_unlock_irqrestore(&prioidx_map_lock, flags);
  55         *prio = prioidx;
  56         return 0;
  57 }
  58
  59 static void put_prioidx(u32 idx)
  60 {
  61         unsigned long flags;
  62
  63         spin_lock_irqsave(&prioidx_map_lock, flags);
  64         clear_bit(idx, prioidx_map);
  65         spin_unlock_irqrestore(&prioidx_map_lock, flags);
  66 }
  67
  68 static int extend_netdev_table(struct net_device *dev, u32 new_len)
  69 {
  70         size_t new_size = sizeof(struct netprio_map) +
  71                            ((sizeof(u32) * new_len));
  72         struct netprio_map *new_priomap = kzalloc(new_size, GFP_KERNEL);
  73         struct netprio_map *old_priomap;
  74         int i;
  75
  76         old_priomap  = rtnl_dereference(dev->priomap);
  77
  78         if (!new_priomap) {
  79                 pr_warn("Unable to alloc new priomap!\n");
  80                 return -ENOMEM;
  81         }
  82
  83         for (i = 0;
  84              old_priomap && (i < old_priomap->priomap_len);
  85              i++)
  86                 new_priomap->priomap[i] = old_priomap->priomap[i];
  87
  88         new_priomap->priomap_len = new_len;
  89
  90         rcu_assign_pointer(dev->priomap, new_priomap);
  91         if (old_priomap)
  92                 kfree_rcu(old_priomap, rcu);
  93         return 0;
  94 }
  95
  96 static int write_update_netdev_table(struct net_device *dev)
  97 {
  98         int ret = 0;
  99         u32 max_len;
 100         struct netprio_map *map;
 101
 102         rtnl_lock();
 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);
 107         rtnl_unlock();
 108
 109         return ret;
 110 }
 111
 112 static int update_netdev_tables(void)
 113 {
 114         int ret = 0;
 115         struct net_device *dev;
 116         u32 max_len;
 117         struct netprio_map *map;
 118
 119         rtnl_lock();
 120         max_len = atomic_read(&max_prioidx) + 1;
 121         for_each_netdev(&init_net, dev) {
 122                 map = rtnl_dereference(dev->priomap);
 123                 /*
 124                  * don't allocate priomap if we didn't
 125                  * change net_prio.ifpriomap (map == NULL),
 126                  * this will speed up skb_update_prio.
 127                  */
 128                 if (map && map->priomap_len < max_len) {
 129                         ret = extend_netdev_table(dev, max_len);
 130                         if (ret < 0)
 131                                 break;
 132                 }
 133         }
 134         rtnl_unlock();
 135         return ret;
 136 }
 137
 138 static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
 139 {
 140         struct cgroup_netprio_state *cs;
 141         int ret = -EINVAL;
 142
 143         cs = kzalloc(sizeof(*cs), GFP_KERNEL);
 144         if (!cs)
 145                 return ERR_PTR(-ENOMEM);
 146
 147         if (cgrp->parent && cgrp_netprio_state(cgrp->parent)->prioidx)
 148                 goto out;
 149
 150         ret = get_prioidx(&cs->prioidx);
 151         if (ret < 0) {
 152                 pr_warn("No space in priority index array\n");
 153                 goto out;
 154         }
 155
 156         ret = update_netdev_tables();
 157         if (ret < 0) {
 158                 put_prioidx(cs->prioidx);
 159                 goto out;
 160         }
 161
 162         return &cs->css;
 163 out:
 164         kfree(cs);
 165         return ERR_PTR(ret);
 166 }
 167
 168 static void cgrp_destroy(struct cgroup *cgrp)
 169 {
 170         struct cgroup_netprio_state *cs;
 171         struct net_device *dev;
 172         struct netprio_map *map;
 173
 174         cs = cgrp_netprio_state(cgrp);
 175         rtnl_lock();
 176         for_each_netdev(&init_net, dev) {
 177                 map = rtnl_dereference(dev->priomap);
 178                 if (map && cs->prioidx < map->priomap_len)
 179                         map->priomap[cs->prioidx] = 0;
 180         }
 181         rtnl_unlock();
 182         put_prioidx(cs->prioidx);
 183         kfree(cs);
 184 }
 185
 186 static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
 187 {
 188         return (u64)cgrp_netprio_state(cgrp)->prioidx;
 189 }
 190
 191 static int read_priomap(struct cgroup *cont, struct cftype *cft,
 192                         struct cgroup_map_cb *cb)
 193 {
 194         struct net_device *dev;
 195         u32 prioidx = cgrp_netprio_state(cont)->prioidx;
 196         u32 priority;
 197         struct netprio_map *map;
 198
 199         rcu_read_lock();
 200         for_each_netdev_rcu(&init_net, dev) {
 201                 map = rcu_dereference(dev->priomap);
 202                 priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;
 203                 cb->fill(cb, dev->name, priority);
 204         }
 205         rcu_read_unlock();
 206         return 0;
 207 }
 208
 209 static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
 210                          const char *buffer)
 211 {
 212         char *devname = kstrdup(buffer, GFP_KERNEL);
 213         int ret = -EINVAL;
 214         u32 prioidx = cgrp_netprio_state(cgrp)->prioidx;
 215         unsigned long priority;
 216         char *priostr;
 217         struct net_device *dev;
 218         struct netprio_map *map;
 219
 220         if (!devname)
 221                 return -ENOMEM;
 222
 223         /*
 224          * Minimally sized valid priomap string
 225          */
 226         if (strlen(devname) < 3)
 227                 goto out_free_devname;
 228
 229         priostr = strstr(devname, " ");
 230         if (!priostr)
 231                 goto out_free_devname;
 232
 233         /*
 234          *Separate the devname from the associated priority
 235          *and advance the priostr poitner to the priority value
 236          */
 237         *priostr = '\0';
 238         priostr++;
 239
 240         /*
 241          * If the priostr points to NULL, we're at the end of the passed
 242          * in string, and its not a valid write
 243          */
 244         if (*priostr == '\0')
 245                 goto out_free_devname;
 246
 247         ret = kstrtoul(priostr, 10, &priority);
 248         if (ret < 0)
 249                 goto out_free_devname;
 250
 251         ret = -ENODEV;
 252
 253         dev = dev_get_by_name(&init_net, devname);
 254         if (!dev)
 255                 goto out_free_devname;
 256
 257         ret = write_update_netdev_table(dev);
 258         if (ret < 0)
 259                 goto out_put_dev;
 260
 261         rcu_read_lock();
 262         map = rcu_dereference(dev->priomap);
 263         if (map)
 264                 map->priomap[prioidx] = priority;
 265         rcu_read_unlock();
 266
 267 out_put_dev:
 268         dev_put(dev);
 269
 270 out_free_devname:
 271         kfree(devname);
 272         return ret;
 273 }
 274
 275 static struct cftype ss_files[] = {
 276         {
 277                 .name = "prioidx",
 278                 .read_u64 = read_prioidx,
 279         },
 280         {
 281                 .name = "ifpriomap",
 282                 .read_map = read_priomap,
 283                 .write_string = write_priomap,
 284         },
 285         { }     /* terminate */
 286 };
 287
 288 struct cgroup_subsys net_prio_subsys = {
 289         .name           = "net_prio",
 290         .create         = cgrp_create,
 291         .destroy        = cgrp_destroy,
 292 #ifdef CONFIG_NETPRIO_CGROUP
 293         .subsys_id      = net_prio_subsys_id,
 294 #endif
 295         .base_cftypes   = ss_files,
 296         .module         = THIS_MODULE
 297 };
 298
 299 static int netprio_device_event(struct notifier_block *unused,
 300                                 unsigned long event, void *ptr)
 301 {
 302         struct net_device *dev = ptr;
 303         struct netprio_map *old;
 304
 305         /*
 306          * Note this is called with rtnl_lock held so we have update side
 307          * protection on our rcu assignments
 308          */
 309
 310         switch (event) {
 311         case NETDEV_UNREGISTER:
 312                 old = rtnl_dereference(dev->priomap);
 313                 RCU_INIT_POINTER(dev->priomap, NULL);
 314                 if (old)
 315                         kfree_rcu(old, rcu);
 316                 break;
 317         }
 318         return NOTIFY_DONE;
 319 }
 320
 321 static struct notifier_block netprio_device_notifier = {
 322         .notifier_call = netprio_device_event
 323 };
 324
 325 static int __init init_cgroup_netprio(void)
 326 {
 327         int ret;
 328
 329         ret = cgroup_load_subsys(&net_prio_subsys);
 330         if (ret)
 331                 goto out;
 332 #ifndef CONFIG_NETPRIO_CGROUP
 333         smp_wmb();
 334         net_prio_subsys_id = net_prio_subsys.subsys_id;
 335 #endif
 336
 337         register_netdevice_notifier(&netprio_device_notifier);
 338
 339 out:
 340         return ret;
 341 }
 342
 343 static void __exit exit_cgroup_netprio(void)
 344 {
 345         struct netprio_map *old;
 346         struct net_device *dev;
 347
 348         unregister_netdevice_notifier(&netprio_device_notifier);
 349
 350         cgroup_unload_subsys(&net_prio_subsys);
 351
 352 #ifndef CONFIG_NETPRIO_CGROUP
 353         net_prio_subsys_id = -1;
 354         synchronize_rcu();
 355 #endif
 356
 357         rtnl_lock();
 358         for_each_netdev(&init_net, dev) {
 359                 old = rtnl_dereference(dev->priomap);
 360                 RCU_INIT_POINTER(dev->priomap, NULL);
 361                 if (old)
 362                         kfree_rcu(old, rcu);
 363         }
 364         rtnl_unlock();
 365 }
 366
 367 module_init(init_cgroup_netprio);
 368 module_exit(exit_cgroup_netprio);
 369 MODULE_LICENSE("GPL v2");