kernel/bpf/offload.c

   1 /*
   2  * Copyright (C) 2017-2018 Netronome Systems, Inc.
   3  *
   4  * This software is licensed under the GNU General License Version 2,
   5  * June 1991 as shown in the file COPYING in the top-level directory of this
   6  * source tree.
   7  *
   8  * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
   9  * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
  10  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  11  * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
  12  * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
  13  * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
  14  */
  15
  16 #include <linux/bpf.h>
  17 #include <linux/bpf_verifier.h>
  18 #include <linux/bug.h>
  19 #include <linux/kdev_t.h>
  20 #include <linux/list.h>
  21 #include <linux/lockdep.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/printk.h>
  24 #include <linux/proc_ns.h>
  25 #include <linux/rhashtable.h>
  26 #include <linux/rtnetlink.h>
  27 #include <linux/rwsem.h>
  28
  29 /* Protects offdevs, members of bpf_offload_netdev and offload members
  30  * of all progs.
  31  * RTNL lock cannot be taken when holding this lock.
  32  */
  33 static DECLARE_RWSEM(bpf_devs_lock);
  34
  35 struct bpf_offload_dev {
  36         const struct bpf_prog_offload_ops *ops;
  37         struct list_head netdevs;
  38         void *priv;
  39 };
  40
  41 struct bpf_offload_netdev {
  42         struct rhash_head l;
  43         struct net_device *netdev;
  44         struct bpf_offload_dev *offdev;
  45         struct list_head progs;
  46         struct list_head maps;
  47         struct list_head offdev_netdevs;
  48 };
  49
  50 static const struct rhashtable_params offdevs_params = {
  51         .nelem_hint             = 4,
  52         .key_len                = sizeof(struct net_device *),
  53         .key_offset             = offsetof(struct bpf_offload_netdev, netdev),
  54         .head_offset            = offsetof(struct bpf_offload_netdev, l),
  55         .automatic_shrinking    = true,
  56 };
  57
  58 static struct rhashtable offdevs;
  59 static bool offdevs_inited;
  60
  61 static int bpf_dev_offload_check(struct net_device *netdev)
  62 {
  63         if (!netdev)
  64                 return -EINVAL;
  65         if (!netdev->netdev_ops->ndo_bpf)
  66                 return -EOPNOTSUPP;
  67         return 0;
  68 }
  69
  70 static struct bpf_offload_netdev *
  71 bpf_offload_find_netdev(struct net_device *netdev)
  72 {
  73         lockdep_assert_held(&bpf_devs_lock);
  74
  75         if (!offdevs_inited)
  76                 return NULL;
  77         return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
  78 }
  79
  80 int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
  81 {
  82         struct bpf_offload_netdev *ondev;
  83         struct bpf_prog_offload *offload;
  84         int err;
  85
  86         if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS &&
  87             attr->prog_type != BPF_PROG_TYPE_XDP)
  88                 return -EINVAL;
  89
  90         if (attr->prog_flags)
  91                 return -EINVAL;
  92
  93         offload = kzalloc(sizeof(*offload), GFP_USER);
  94         if (!offload)
  95                 return -ENOMEM;
  96
  97         offload->prog = prog;
  98
  99         offload->netdev = dev_get_by_index(current->nsproxy->net_ns,
 100                                            attr->prog_ifindex);
 101         err = bpf_dev_offload_check(offload->netdev);
 102         if (err)
 103                 goto err_maybe_put;
 104
 105         down_write(&bpf_devs_lock);
 106         ondev = bpf_offload_find_netdev(offload->netdev);
 107         if (!ondev) {
 108                 err = -EINVAL;
 109                 goto err_unlock;
 110         }
 111         offload->offdev = ondev->offdev;
 112         prog->aux->offload = offload;
 113         list_add_tail(&offload->offloads, &ondev->progs);
 114         dev_put(offload->netdev);
 115         up_write(&bpf_devs_lock);
 116
 117         return 0;
 118 err_unlock:
 119         up_write(&bpf_devs_lock);
 120 err_maybe_put:
 121         if (offload->netdev)
 122                 dev_put(offload->netdev);
 123         kfree(offload);
 124         return err;
 125 }
 126
 127 int bpf_prog_offload_verifier_prep(struct bpf_prog *prog)
 128 {
 129         struct bpf_prog_offload *offload;
 130         int ret = -ENODEV;
 131
 132         down_read(&bpf_devs_lock);
 133         offload = prog->aux->offload;
 134         if (offload) {
 135                 ret = offload->offdev->ops->prepare(prog);
 136                 offload->dev_state = !ret;
 137         }
 138         up_read(&bpf_devs_lock);
 139
 140         return ret;
 141 }
 142
 143 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
 144                                  int insn_idx, int prev_insn_idx)
 145 {
 146         struct bpf_prog_offload *offload;
 147         int ret = -ENODEV;
 148
 149         down_read(&bpf_devs_lock);
 150         offload = env->prog->aux->offload;
 151         if (offload)
 152                 ret = offload->offdev->ops->insn_hook(env, insn_idx,
 153                                                       prev_insn_idx);
 154         up_read(&bpf_devs_lock);
 155
 156         return ret;
 157 }
 158
 159 int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
 160 {
 161         struct bpf_prog_offload *offload;
 162         int ret = -ENODEV;
 163
 164         down_read(&bpf_devs_lock);
 165         offload = env->prog->aux->offload;
 166         if (offload) {
 167                 if (offload->offdev->ops->finalize)
 168                         ret = offload->offdev->ops->finalize(env);
 169                 else
 170                         ret = 0;
 171         }
 172         up_read(&bpf_devs_lock);
 173
 174         return ret;
 175 }
 176
 177 void
 178 bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
 179                               struct bpf_insn *insn)
 180 {
 181         const struct bpf_prog_offload_ops *ops;
 182         struct bpf_prog_offload *offload;
 183         int ret = -EOPNOTSUPP;
 184
 185         down_read(&bpf_devs_lock);
 186         offload = env->prog->aux->offload;
 187         if (offload) {
 188                 ops = offload->offdev->ops;
 189                 if (!offload->opt_failed && ops->replace_insn)
 190                         ret = ops->replace_insn(env, off, insn);
 191                 offload->opt_failed |= ret;
 192         }
 193         up_read(&bpf_devs_lock);
 194 }
 195
 196 void
 197 bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
 198 {
 199         struct bpf_prog_offload *offload;
 200         int ret = -EOPNOTSUPP;
 201
 202         down_read(&bpf_devs_lock);
 203         offload = env->prog->aux->offload;
 204         if (offload) {
 205                 if (!offload->opt_failed && offload->offdev->ops->remove_insns)
 206                         ret = offload->offdev->ops->remove_insns(env, off, cnt);
 207                 offload->opt_failed |= ret;
 208         }
 209         up_read(&bpf_devs_lock);
 210 }
 211
 212 static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
 213 {
 214         struct bpf_prog_offload *offload = prog->aux->offload;
 215
 216         if (offload->dev_state)
 217                 offload->offdev->ops->destroy(prog);
 218
 219         /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
 220         bpf_prog_free_id(prog, true);
 221
 222         list_del_init(&offload->offloads);
 223         kfree(offload);
 224         prog->aux->offload = NULL;
 225 }
 226
 227 void bpf_prog_offload_destroy(struct bpf_prog *prog)
 228 {
 229         down_write(&bpf_devs_lock);
 230         if (prog->aux->offload)
 231                 __bpf_prog_offload_destroy(prog);
 232         up_write(&bpf_devs_lock);
 233 }
 234
 235 static int bpf_prog_offload_translate(struct bpf_prog *prog)
 236 {
 237         struct bpf_prog_offload *offload;
 238         int ret = -ENODEV;
 239
 240         down_read(&bpf_devs_lock);
 241         offload = prog->aux->offload;
 242         if (offload)
 243                 ret = offload->offdev->ops->translate(prog);
 244         up_read(&bpf_devs_lock);
 245
 246         return ret;
 247 }
 248
 249 static unsigned int bpf_prog_warn_on_exec(const void *ctx,
 250                                           const struct bpf_insn *insn)
 251 {
 252         WARN(1, "attempt to execute device eBPF program on the host!");
 253         return 0;
 254 }
 255
 256 int bpf_prog_offload_compile(struct bpf_prog *prog)
 257 {
 258         prog->bpf_func = bpf_prog_warn_on_exec;
 259
 260         return bpf_prog_offload_translate(prog);
 261 }
 262
 263 struct ns_get_path_bpf_prog_args {
 264         struct bpf_prog *prog;
 265         struct bpf_prog_info *info;
 266 };
 267
 268 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data)
 269 {
 270         struct ns_get_path_bpf_prog_args *args = private_data;
 271         struct bpf_prog_aux *aux = args->prog->aux;
 272         struct ns_common *ns;
 273         struct net *net;
 274
 275         rtnl_lock();
 276         down_read(&bpf_devs_lock);
 277
 278         if (aux->offload) {
 279                 args->info->ifindex = aux->offload->netdev->ifindex;
 280                 net = dev_net(aux->offload->netdev);
 281                 get_net(net);
 282                 ns = &net->ns;
 283         } else {
 284                 args->info->ifindex = 0;
 285                 ns = NULL;
 286         }
 287
 288         up_read(&bpf_devs_lock);
 289         rtnl_unlock();
 290
 291         return ns;
 292 }
 293
 294 int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
 295                                struct bpf_prog *prog)
 296 {
 297         struct ns_get_path_bpf_prog_args args = {
 298                 .prog   = prog,
 299                 .info   = info,
 300         };
 301         struct bpf_prog_aux *aux = prog->aux;
 302         struct inode *ns_inode;
 303         struct path ns_path;
 304         char __user *uinsns;
 305         int res;
 306         u32 ulen;
 307
 308         res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
 309         if (res) {
 310                 if (!info->ifindex)
 311                         return -ENODEV;
 312                 return res;
 313         }
 314
 315         down_read(&bpf_devs_lock);
 316
 317         if (!aux->offload) {
 318                 up_read(&bpf_devs_lock);
 319                 return -ENODEV;
 320         }
 321
 322         ulen = info->jited_prog_len;
 323         info->jited_prog_len = aux->offload->jited_len;
 324         if (info->jited_prog_len && ulen) {
 325                 uinsns = u64_to_user_ptr(info->jited_prog_insns);
 326                 ulen = min_t(u32, info->jited_prog_len, ulen);
 327                 if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) {
 328                         up_read(&bpf_devs_lock);
 329                         return -EFAULT;
 330                 }
 331         }
 332
 333         up_read(&bpf_devs_lock);
 334
 335         ns_inode = ns_path.dentry->d_inode;
 336         info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
 337         info->netns_ino = ns_inode->i_ino;
 338         path_put(&ns_path);
 339
 340         return 0;
 341 }
 342
 343 const struct bpf_prog_ops bpf_offload_prog_ops = {
 344 };
 345
 346 static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap,
 347                                enum bpf_netdev_command cmd)
 348 {
 349         struct netdev_bpf data = {};
 350         struct net_device *netdev;
 351
 352         ASSERT_RTNL();
 353
 354         data.command = cmd;
 355         data.offmap = offmap;
 356         /* Caller must make sure netdev is valid */
 357         netdev = offmap->netdev;
 358
 359         return netdev->netdev_ops->ndo_bpf(netdev, &data);
 360 }
 361
 362 struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
 363 {
 364         struct net *net = current->nsproxy->net_ns;
 365         struct bpf_offload_netdev *ondev;
 366         struct bpf_offloaded_map *offmap;
 367         int err;
 368
 369         if (!capable(CAP_SYS_ADMIN))
 370                 return ERR_PTR(-EPERM);
 371         if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
 372             attr->map_type != BPF_MAP_TYPE_HASH)
 373                 return ERR_PTR(-EINVAL);
 374
 375         offmap = kzalloc(sizeof(*offmap), GFP_USER);
 376         if (!offmap)
 377                 return ERR_PTR(-ENOMEM);
 378
 379         bpf_map_init_from_attr(&offmap->map, attr);
 380
 381         rtnl_lock();
 382         down_write(&bpf_devs_lock);
 383         offmap->netdev = __dev_get_by_index(net, attr->map_ifindex);
 384         err = bpf_dev_offload_check(offmap->netdev);
 385         if (err)
 386                 goto err_unlock;
 387
 388         ondev = bpf_offload_find_netdev(offmap->netdev);
 389         if (!ondev) {
 390                 err = -EINVAL;
 391                 goto err_unlock;
 392         }
 393
 394         err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC);
 395         if (err)
 396                 goto err_unlock;
 397
 398         list_add_tail(&offmap->offloads, &ondev->maps);
 399         up_write(&bpf_devs_lock);
 400         rtnl_unlock();
 401
 402         return &offmap->map;
 403
 404 err_unlock:
 405         up_write(&bpf_devs_lock);
 406         rtnl_unlock();
 407         kfree(offmap);
 408         return ERR_PTR(err);
 409 }
 410
 411 static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap)
 412 {
 413         WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE));
 414         /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */
 415         bpf_map_free_id(&offmap->map, true);
 416         list_del_init(&offmap->offloads);
 417         offmap->netdev = NULL;
 418 }
 419
 420 void bpf_map_offload_map_free(struct bpf_map *map)
 421 {
 422         struct bpf_offloaded_map *offmap = map_to_offmap(map);
 423
 424         rtnl_lock();
 425         down_write(&bpf_devs_lock);
 426         if (offmap->netdev)
 427                 __bpf_map_offload_destroy(offmap);
 428         up_write(&bpf_devs_lock);
 429         rtnl_unlock();
 430
 431         kfree(offmap);
 432 }
 433
 434 int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value)
 435 {
 436         struct bpf_offloaded_map *offmap = map_to_offmap(map);
 437         int ret = -ENODEV;
 438
 439         down_read(&bpf_devs_lock);
 440         if (offmap->netdev)
 441                 ret = offmap->dev_ops->map_lookup_elem(offmap, key, value);
 442         up_read(&bpf_devs_lock);
 443
 444         return ret;
 445 }
 446
 447 int bpf_map_offload_update_elem(struct bpf_map *map,
 448                                 void *key, void *value, u64 flags)
 449 {
 450         struct bpf_offloaded_map *offmap = map_to_offmap(map);
 451         int ret = -ENODEV;
 452
 453         if (unlikely(flags > BPF_EXIST))
 454                 return -EINVAL;
 455
 456         down_read(&bpf_devs_lock);
 457         if (offmap->netdev)
 458                 ret = offmap->dev_ops->map_update_elem(offmap, key, value,
 459                                                        flags);
 460         up_read(&bpf_devs_lock);
 461
 462         return ret;
 463 }
 464
 465 int bpf_map_offload_delete_elem(struct bpf_map *map, void *key)
 466 {
 467         struct bpf_offloaded_map *offmap = map_to_offmap(map);
 468         int ret = -ENODEV;
 469
 470         down_read(&bpf_devs_lock);
 471         if (offmap->netdev)
 472                 ret = offmap->dev_ops->map_delete_elem(offmap, key);
 473         up_read(&bpf_devs_lock);
 474
 475         return ret;
 476 }
 477
 478 int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key)
 479 {
 480         struct bpf_offloaded_map *offmap = map_to_offmap(map);
 481         int ret = -ENODEV;
 482
 483         down_read(&bpf_devs_lock);
 484         if (offmap->netdev)
 485                 ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key);
 486         up_read(&bpf_devs_lock);
 487
 488         return ret;
 489 }
 490
 491 struct ns_get_path_bpf_map_args {
 492         struct bpf_offloaded_map *offmap;
 493         struct bpf_map_info *info;
 494 };
 495
 496 static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data)
 497 {
 498         struct ns_get_path_bpf_map_args *args = private_data;
 499         struct ns_common *ns;
 500         struct net *net;
 501
 502         rtnl_lock();
 503         down_read(&bpf_devs_lock);
 504
 505         if (args->offmap->netdev) {
 506                 args->info->ifindex = args->offmap->netdev->ifindex;
 507                 net = dev_net(args->offmap->netdev);
 508                 get_net(net);
 509                 ns = &net->ns;
 510         } else {
 511                 args->info->ifindex = 0;
 512                 ns = NULL;
 513         }
 514
 515         up_read(&bpf_devs_lock);
 516         rtnl_unlock();
 517
 518         return ns;
 519 }
 520
 521 int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
 522 {
 523         struct ns_get_path_bpf_map_args args = {
 524                 .offmap = map_to_offmap(map),
 525                 .info   = info,
 526         };
 527         struct inode *ns_inode;
 528         struct path ns_path;
 529         int res;
 530
 531         res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
 532         if (res) {
 533                 if (!info->ifindex)
 534                         return -ENODEV;
 535                 return res;
 536         }
 537
 538         ns_inode = ns_path.dentry->d_inode;
 539         info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
 540         info->netns_ino = ns_inode->i_ino;
 541         path_put(&ns_path);
 542
 543         return 0;
 544 }
 545
 546 static bool __bpf_offload_dev_match(struct bpf_prog *prog,
 547                                     struct net_device *netdev)
 548 {
 549         struct bpf_offload_netdev *ondev1, *ondev2;
 550         struct bpf_prog_offload *offload;
 551
 552         if (!bpf_prog_is_dev_bound(prog->aux))
 553                 return false;
 554
 555         offload = prog->aux->offload;
 556         if (!offload)
 557                 return false;
 558         if (offload->netdev == netdev)
 559                 return true;
 560
 561         ondev1 = bpf_offload_find_netdev(offload->netdev);
 562         ondev2 = bpf_offload_find_netdev(netdev);
 563
 564         return ondev1 && ondev2 && ondev1->offdev == ondev2->offdev;
 565 }
 566
 567 bool bpf_offload_dev_match(struct bpf_prog *prog, struct net_device *netdev)
 568 {
 569         bool ret;
 570
 571         down_read(&bpf_devs_lock);
 572         ret = __bpf_offload_dev_match(prog, netdev);
 573         up_read(&bpf_devs_lock);
 574
 575         return ret;
 576 }
 577 EXPORT_SYMBOL_GPL(bpf_offload_dev_match);
 578
 579 bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map)
 580 {
 581         struct bpf_offloaded_map *offmap;
 582         bool ret;
 583
 584         if (!bpf_map_is_dev_bound(map))
 585                 return bpf_map_offload_neutral(map);
 586         offmap = map_to_offmap(map);
 587
 588         down_read(&bpf_devs_lock);
 589         ret = __bpf_offload_dev_match(prog, offmap->netdev);
 590         up_read(&bpf_devs_lock);
 591
 592         return ret;
 593 }
 594
 595 int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
 596                                     struct net_device *netdev)
 597 {
 598         struct bpf_offload_netdev *ondev;
 599         int err;
 600
 601         ondev = kzalloc(sizeof(*ondev), GFP_KERNEL);
 602         if (!ondev)
 603                 return -ENOMEM;
 604
 605         ondev->netdev = netdev;
 606         ondev->offdev = offdev;
 607         INIT_LIST_HEAD(&ondev->progs);
 608         INIT_LIST_HEAD(&ondev->maps);
 609
 610         down_write(&bpf_devs_lock);
 611         err = rhashtable_insert_fast(&offdevs, &ondev->l, offdevs_params);
 612         if (err) {
 613                 netdev_warn(netdev, "failed to register for BPF offload\n");
 614                 goto err_unlock_free;
 615         }
 616
 617         list_add(&ondev->offdev_netdevs, &offdev->netdevs);
 618         up_write(&bpf_devs_lock);
 619         return 0;
 620
 621 err_unlock_free:
 622         up_write(&bpf_devs_lock);
 623         kfree(ondev);
 624         return err;
 625 }
 626 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_register);
 627
 628 void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
 629                                        struct net_device *netdev)
 630 {
 631         struct bpf_offload_netdev *ondev, *altdev;
 632         struct bpf_offloaded_map *offmap, *mtmp;
 633         struct bpf_prog_offload *offload, *ptmp;
 634
 635         ASSERT_RTNL();
 636
 637         down_write(&bpf_devs_lock);
 638         ondev = rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
 639         if (WARN_ON(!ondev))
 640                 goto unlock;
 641
 642         WARN_ON(rhashtable_remove_fast(&offdevs, &ondev->l, offdevs_params));
 643         list_del(&ondev->offdev_netdevs);
 644
 645         /* Try to move the objects to another netdev of the device */
 646         altdev = list_first_entry_or_null(&offdev->netdevs,
 647                                           struct bpf_offload_netdev,
 648                                           offdev_netdevs);
 649         if (altdev) {
 650                 list_for_each_entry(offload, &ondev->progs, offloads)
 651                         offload->netdev = altdev->netdev;
 652                 list_splice_init(&ondev->progs, &altdev->progs);
 653
 654                 list_for_each_entry(offmap, &ondev->maps, offloads)
 655                         offmap->netdev = altdev->netdev;
 656                 list_splice_init(&ondev->maps, &altdev->maps);
 657         } else {
 658                 list_for_each_entry_safe(offload, ptmp, &ondev->progs, offloads)
 659                         __bpf_prog_offload_destroy(offload->prog);
 660                 list_for_each_entry_safe(offmap, mtmp, &ondev->maps, offloads)
 661                         __bpf_map_offload_destroy(offmap);
 662         }
 663
 664         WARN_ON(!list_empty(&ondev->progs));
 665         WARN_ON(!list_empty(&ondev->maps));
 666         kfree(ondev);
 667 unlock:
 668         up_write(&bpf_devs_lock);
 669 }
 670 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
 671
 672 struct bpf_offload_dev *
 673 bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
 674 {
 675         struct bpf_offload_dev *offdev;
 676         int err;
 677
 678         down_write(&bpf_devs_lock);
 679         if (!offdevs_inited) {
 680                 err = rhashtable_init(&offdevs, &offdevs_params);
 681                 if (err) {
 682                         up_write(&bpf_devs_lock);
 683                         return ERR_PTR(err);
 684                 }
 685                 offdevs_inited = true;
 686         }
 687         up_write(&bpf_devs_lock);
 688
 689         offdev = kzalloc(sizeof(*offdev), GFP_KERNEL);
 690         if (!offdev)
 691                 return ERR_PTR(-ENOMEM);
 692
 693         offdev->ops = ops;
 694         offdev->priv = priv;
 695         INIT_LIST_HEAD(&offdev->netdevs);
 696
 697         return offdev;
 698 }
 699 EXPORT_SYMBOL_GPL(bpf_offload_dev_create);
 700
 701 void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
 702 {
 703         WARN_ON(!list_empty(&offdev->netdevs));
 704         kfree(offdev);
 705 }
 706 EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);
 707
 708 void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
 709 {
 710         return offdev->priv;
 711 }
 712 EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);