1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Minimal file system backend for holding eBPF maps and programs, 4 * used by bpf(2) object pinning. 5 * 6 * Authors: 7 * 8 * Daniel Borkmann <daniel@iogearbox.net> 9 */ 10 11 #include <linux/init.h> 12 #include <linux/magic.h> 13 #include <linux/major.h> 14 #include <linux/mount.h> 15 #include <linux/namei.h> 16 #include <linux/fs.h> 17 #include <linux/fs_context.h> 18 #include <linux/fs_parser.h> 19 #include <linux/kdev_t.h> 20 #include <linux/filter.h> 21 #include <linux/bpf.h> 22 #include <linux/bpf_trace.h> 23 #include "preload/bpf_preload.h" 24 25 enum bpf_type { 26 BPF_TYPE_UNSPEC = 0, 27 BPF_TYPE_PROG, 28 BPF_TYPE_MAP, 29 BPF_TYPE_LINK, 30 }; 31 32 static void *bpf_any_get(void *raw, enum bpf_type type) 33 { 34 switch (type) { 35 case BPF_TYPE_PROG: 36 bpf_prog_inc(raw); 37 break; 38 case BPF_TYPE_MAP: 39 bpf_map_inc_with_uref(raw); 40 break; 41 case BPF_TYPE_LINK: 42 bpf_link_inc(raw); 43 break; 44 default: 45 WARN_ON_ONCE(1); 46 break; 47 } 48 49 return raw; 50 } 51 52 static void bpf_any_put(void *raw, enum bpf_type type) 53 { 54 switch (type) { 55 case BPF_TYPE_PROG: 56 bpf_prog_put(raw); 57 break; 58 case BPF_TYPE_MAP: 59 bpf_map_put_with_uref(raw); 60 break; 61 case BPF_TYPE_LINK: 62 bpf_link_put(raw); 63 break; 64 default: 65 WARN_ON_ONCE(1); 66 break; 67 } 68 } 69 70 static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type) 71 { 72 void *raw; 73 74 raw = bpf_map_get_with_uref(ufd); 75 if (!IS_ERR(raw)) { 76 *type = BPF_TYPE_MAP; 77 return raw; 78 } 79 80 raw = bpf_prog_get(ufd); 81 if (!IS_ERR(raw)) { 82 *type = BPF_TYPE_PROG; 83 return raw; 84 } 85 86 raw = bpf_link_get_from_fd(ufd); 87 if (!IS_ERR(raw)) { 88 *type = BPF_TYPE_LINK; 89 return raw; 90 } 91 92 return ERR_PTR(-EINVAL); 93 } 94 95 static const struct inode_operations bpf_dir_iops; 96 97 static const struct inode_operations bpf_prog_iops = { }; 98 static const struct inode_operations bpf_map_iops = { }; 99 static const struct inode_operations bpf_link_iops = { }; 100 101 static struct inode *bpf_get_inode(struct super_block *sb, 102 const struct inode *dir, 103 umode_t mode) 104 { 105 struct inode *inode; 106 107 switch (mode & S_IFMT) { 108 case S_IFDIR: 109 case S_IFREG: 110 case S_IFLNK: 111 break; 112 default: 113 return ERR_PTR(-EINVAL); 114 } 115 116 inode = new_inode(sb); 117 if (!inode) 118 return ERR_PTR(-ENOSPC); 119 120 inode->i_ino = get_next_ino(); 121 simple_inode_init_ts(inode); 122 123 inode_init_owner(&nop_mnt_idmap, inode, dir, mode); 124 125 return inode; 126 } 127 128 static int bpf_inode_type(const struct inode *inode, enum bpf_type *type) 129 { 130 *type = BPF_TYPE_UNSPEC; 131 if (inode->i_op == &bpf_prog_iops) 132 *type = BPF_TYPE_PROG; 133 else if (inode->i_op == &bpf_map_iops) 134 *type = BPF_TYPE_MAP; 135 else if (inode->i_op == &bpf_link_iops) 136 *type = BPF_TYPE_LINK; 137 else 138 return -EACCES; 139 140 return 0; 141 } 142 143 static void bpf_dentry_finalize(struct dentry *dentry, struct inode *inode, 144 struct inode *dir) 145 { 146 d_instantiate(dentry, inode); 147 dget(dentry); 148 149 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); 150 } 151 152 static int bpf_mkdir(struct mnt_idmap *idmap, struct inode *dir, 153 struct dentry *dentry, umode_t mode) 154 { 155 struct inode *inode; 156 157 inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFDIR); 158 if (IS_ERR(inode)) 159 return PTR_ERR(inode); 160 161 inode->i_op = &bpf_dir_iops; 162 inode->i_fop = &simple_dir_operations; 163 164 inc_nlink(inode); 165 inc_nlink(dir); 166 167 bpf_dentry_finalize(dentry, inode, dir); 168 return 0; 169 } 170 171 struct map_iter { 172 void *key; 173 bool done; 174 }; 175 176 static struct map_iter *map_iter(struct seq_file *m) 177 { 178 return m->private; 179 } 180 181 static struct bpf_map *seq_file_to_map(struct seq_file *m) 182 { 183 return file_inode(m->file)->i_private; 184 } 185 186 static void map_iter_free(struct map_iter *iter) 187 { 188 if (iter) { 189 kfree(iter->key); 190 kfree(iter); 191 } 192 } 193 194 static struct map_iter *map_iter_alloc(struct bpf_map *map) 195 { 196 struct map_iter *iter; 197 198 iter = kzalloc(sizeof(*iter), GFP_KERNEL | __GFP_NOWARN); 199 if (!iter) 200 goto error; 201 202 iter->key = kzalloc(map->key_size, GFP_KERNEL | __GFP_NOWARN); 203 if (!iter->key) 204 goto error; 205 206 return iter; 207 208 error: 209 map_iter_free(iter); 210 return NULL; 211 } 212 213 static void *map_seq_next(struct seq_file *m, void *v, loff_t *pos) 214 { 215 struct bpf_map *map = seq_file_to_map(m); 216 void *key = map_iter(m)->key; 217 void *prev_key; 218 219 (*pos)++; 220 if (map_iter(m)->done) 221 return NULL; 222 223 if (unlikely(v == SEQ_START_TOKEN)) 224 prev_key = NULL; 225 else 226 prev_key = key; 227 228 rcu_read_lock(); 229 if (map->ops->map_get_next_key(map, prev_key, key)) { 230 map_iter(m)->done = true; 231 key = NULL; 232 } 233 rcu_read_unlock(); 234 return key; 235 } 236 237 static void *map_seq_start(struct seq_file *m, loff_t *pos) 238 { 239 if (map_iter(m)->done) 240 return NULL; 241 242 return *pos ? map_iter(m)->key : SEQ_START_TOKEN; 243 } 244 245 static void map_seq_stop(struct seq_file *m, void *v) 246 { 247 } 248 249 static int map_seq_show(struct seq_file *m, void *v) 250 { 251 struct bpf_map *map = seq_file_to_map(m); 252 void *key = map_iter(m)->key; 253 254 if (unlikely(v == SEQ_START_TOKEN)) { 255 seq_puts(m, "# WARNING!! The output is for debug purpose only\n"); 256 seq_puts(m, "# WARNING!! The output format will change\n"); 257 } else { 258 map->ops->map_seq_show_elem(map, key, m); 259 } 260 261 return 0; 262 } 263 264 static const struct seq_operations bpffs_map_seq_ops = { 265 .start = map_seq_start, 266 .next = map_seq_next, 267 .show = map_seq_show, 268 .stop = map_seq_stop, 269 }; 270 271 static int bpffs_map_open(struct inode *inode, struct file *file) 272 { 273 struct bpf_map *map = inode->i_private; 274 struct map_iter *iter; 275 struct seq_file *m; 276 int err; 277 278 iter = map_iter_alloc(map); 279 if (!iter) 280 return -ENOMEM; 281 282 err = seq_open(file, &bpffs_map_seq_ops); 283 if (err) { 284 map_iter_free(iter); 285 return err; 286 } 287 288 m = file->private_data; 289 m->private = iter; 290 291 return 0; 292 } 293 294 static int bpffs_map_release(struct inode *inode, struct file *file) 295 { 296 struct seq_file *m = file->private_data; 297 298 map_iter_free(map_iter(m)); 299 300 return seq_release(inode, file); 301 } 302 303 /* bpffs_map_fops should only implement the basic 304 * read operation for a BPF map. The purpose is to 305 * provide a simple user intuitive way to do 306 * "cat bpffs/pathto/a-pinned-map". 307 * 308 * Other operations (e.g. write, lookup...) should be realized by 309 * the userspace tools (e.g. bpftool) through the 310 * BPF_OBJ_GET_INFO_BY_FD and the map's lookup/update 311 * interface. 312 */ 313 static const struct file_operations bpffs_map_fops = { 314 .open = bpffs_map_open, 315 .read = seq_read, 316 .release = bpffs_map_release, 317 }; 318 319 static int bpffs_obj_open(struct inode *inode, struct file *file) 320 { 321 return -EIO; 322 } 323 324 static const struct file_operations bpffs_obj_fops = { 325 .open = bpffs_obj_open, 326 }; 327 328 static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw, 329 const struct inode_operations *iops, 330 const struct file_operations *fops) 331 { 332 struct inode *dir = dentry->d_parent->d_inode; 333 struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode); 334 if (IS_ERR(inode)) 335 return PTR_ERR(inode); 336 337 inode->i_op = iops; 338 inode->i_fop = fops; 339 inode->i_private = raw; 340 341 bpf_dentry_finalize(dentry, inode, dir); 342 return 0; 343 } 344 345 static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg) 346 { 347 return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops, 348 &bpffs_obj_fops); 349 } 350 351 static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg) 352 { 353 struct bpf_map *map = arg; 354 355 return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops, 356 bpf_map_support_seq_show(map) ? 357 &bpffs_map_fops : &bpffs_obj_fops); 358 } 359 360 static int bpf_mklink(struct dentry *dentry, umode_t mode, void *arg) 361 { 362 struct bpf_link *link = arg; 363 364 return bpf_mkobj_ops(dentry, mode, arg, &bpf_link_iops, 365 bpf_link_is_iter(link) ? 366 &bpf_iter_fops : &bpffs_obj_fops); 367 } 368 369 static struct dentry * 370 bpf_lookup(struct inode *dir, struct dentry *dentry, unsigned flags) 371 { 372 /* Dots in names (e.g. "/sys/fs/bpf/foo.bar") are reserved for future 373 * extensions. That allows popoulate_bpffs() create special files. 374 */ 375 if ((dir->i_mode & S_IALLUGO) && 376 strchr(dentry->d_name.name, '.')) 377 return ERR_PTR(-EPERM); 378 379 return simple_lookup(dir, dentry, flags); 380 } 381 382 static int bpf_symlink(struct mnt_idmap *idmap, struct inode *dir, 383 struct dentry *dentry, const char *target) 384 { 385 char *link = kstrdup(target, GFP_USER | __GFP_NOWARN); 386 struct inode *inode; 387 388 if (!link) 389 return -ENOMEM; 390 391 inode = bpf_get_inode(dir->i_sb, dir, S_IRWXUGO | S_IFLNK); 392 if (IS_ERR(inode)) { 393 kfree(link); 394 return PTR_ERR(inode); 395 } 396 397 inode->i_op = &simple_symlink_inode_operations; 398 inode->i_link = link; 399 400 bpf_dentry_finalize(dentry, inode, dir); 401 return 0; 402 } 403 404 static const struct inode_operations bpf_dir_iops = { 405 .lookup = bpf_lookup, 406 .mkdir = bpf_mkdir, 407 .symlink = bpf_symlink, 408 .rmdir = simple_rmdir, 409 .rename = simple_rename, 410 .link = simple_link, 411 .unlink = simple_unlink, 412 }; 413 414 /* pin iterator link into bpffs */ 415 static int bpf_iter_link_pin_kernel(struct dentry *parent, 416 const char *name, struct bpf_link *link) 417 { 418 umode_t mode = S_IFREG | S_IRUSR; 419 struct dentry *dentry; 420 int ret; 421 422 inode_lock(parent->d_inode); 423 dentry = lookup_one_len(name, parent, strlen(name)); 424 if (IS_ERR(dentry)) { 425 inode_unlock(parent->d_inode); 426 return PTR_ERR(dentry); 427 } 428 ret = bpf_mkobj_ops(dentry, mode, link, &bpf_link_iops, 429 &bpf_iter_fops); 430 dput(dentry); 431 inode_unlock(parent->d_inode); 432 return ret; 433 } 434 435 static int bpf_obj_do_pin(int path_fd, const char __user *pathname, void *raw, 436 enum bpf_type type) 437 { 438 struct dentry *dentry; 439 struct inode *dir; 440 struct path path; 441 umode_t mode; 442 int ret; 443 444 dentry = user_path_create(path_fd, pathname, &path, 0); 445 if (IS_ERR(dentry)) 446 return PTR_ERR(dentry); 447 448 dir = d_inode(path.dentry); 449 if (dir->i_op != &bpf_dir_iops) { 450 ret = -EPERM; 451 goto out; 452 } 453 454 mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask()); 455 ret = security_path_mknod(&path, dentry, mode, 0); 456 if (ret) 457 goto out; 458 459 switch (type) { 460 case BPF_TYPE_PROG: 461 ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw); 462 break; 463 case BPF_TYPE_MAP: 464 ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw); 465 break; 466 case BPF_TYPE_LINK: 467 ret = vfs_mkobj(dentry, mode, bpf_mklink, raw); 468 break; 469 default: 470 ret = -EPERM; 471 } 472 out: 473 done_path_create(&path, dentry); 474 return ret; 475 } 476 477 int bpf_obj_pin_user(u32 ufd, int path_fd, const char __user *pathname) 478 { 479 enum bpf_type type; 480 void *raw; 481 int ret; 482 483 raw = bpf_fd_probe_obj(ufd, &type); 484 if (IS_ERR(raw)) 485 return PTR_ERR(raw); 486 487 ret = bpf_obj_do_pin(path_fd, pathname, raw, type); 488 if (ret != 0) 489 bpf_any_put(raw, type); 490 491 return ret; 492 } 493 494 static void *bpf_obj_do_get(int path_fd, const char __user *pathname, 495 enum bpf_type *type, int flags) 496 { 497 struct inode *inode; 498 struct path path; 499 void *raw; 500 int ret; 501 502 ret = user_path_at(path_fd, pathname, LOOKUP_FOLLOW, &path); 503 if (ret) 504 return ERR_PTR(ret); 505 506 inode = d_backing_inode(path.dentry); 507 ret = path_permission(&path, ACC_MODE(flags)); 508 if (ret) 509 goto out; 510 511 ret = bpf_inode_type(inode, type); 512 if (ret) 513 goto out; 514 515 raw = bpf_any_get(inode->i_private, *type); 516 if (!IS_ERR(raw)) 517 touch_atime(&path); 518 519 path_put(&path); 520 return raw; 521 out: 522 path_put(&path); 523 return ERR_PTR(ret); 524 } 525 526 int bpf_obj_get_user(int path_fd, const char __user *pathname, int flags) 527 { 528 enum bpf_type type = BPF_TYPE_UNSPEC; 529 int f_flags; 530 void *raw; 531 int ret; 532 533 f_flags = bpf_get_file_flag(flags); 534 if (f_flags < 0) 535 return f_flags; 536 537 raw = bpf_obj_do_get(path_fd, pathname, &type, f_flags); 538 if (IS_ERR(raw)) 539 return PTR_ERR(raw); 540 541 if (type == BPF_TYPE_PROG) 542 ret = bpf_prog_new_fd(raw); 543 else if (type == BPF_TYPE_MAP) 544 ret = bpf_map_new_fd(raw, f_flags); 545 else if (type == BPF_TYPE_LINK) 546 ret = (f_flags != O_RDWR) ? -EINVAL : bpf_link_new_fd(raw); 547 else 548 return -ENOENT; 549 550 if (ret < 0) 551 bpf_any_put(raw, type); 552 return ret; 553 } 554 555 static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type) 556 { 557 struct bpf_prog *prog; 558 int ret = inode_permission(&nop_mnt_idmap, inode, MAY_READ); 559 if (ret) 560 return ERR_PTR(ret); 561 562 if (inode->i_op == &bpf_map_iops) 563 return ERR_PTR(-EINVAL); 564 if (inode->i_op == &bpf_link_iops) 565 return ERR_PTR(-EINVAL); 566 if (inode->i_op != &bpf_prog_iops) 567 return ERR_PTR(-EACCES); 568 569 prog = inode->i_private; 570 571 ret = security_bpf_prog(prog); 572 if (ret < 0) 573 return ERR_PTR(ret); 574 575 if (!bpf_prog_get_ok(prog, &type, false)) 576 return ERR_PTR(-EINVAL); 577 578 bpf_prog_inc(prog); 579 return prog; 580 } 581 582 struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type) 583 { 584 struct bpf_prog *prog; 585 struct path path; 586 int ret = kern_path(name, LOOKUP_FOLLOW, &path); 587 if (ret) 588 return ERR_PTR(ret); 589 prog = __get_prog_inode(d_backing_inode(path.dentry), type); 590 if (!IS_ERR(prog)) 591 touch_atime(&path); 592 path_put(&path); 593 return prog; 594 } 595 EXPORT_SYMBOL(bpf_prog_get_type_path); 596 597 /* 598 * Display the mount options in /proc/mounts. 599 */ 600 static int bpf_show_options(struct seq_file *m, struct dentry *root) 601 { 602 umode_t mode = d_inode(root)->i_mode & S_IALLUGO & ~S_ISVTX; 603 604 if (mode != S_IRWXUGO) 605 seq_printf(m, ",mode=%o", mode); 606 return 0; 607 } 608 609 static void bpf_free_inode(struct inode *inode) 610 { 611 enum bpf_type type; 612 613 if (S_ISLNK(inode->i_mode)) 614 kfree(inode->i_link); 615 if (!bpf_inode_type(inode, &type)) 616 bpf_any_put(inode->i_private, type); 617 free_inode_nonrcu(inode); 618 } 619 620 static const struct super_operations bpf_super_ops = { 621 .statfs = simple_statfs, 622 .drop_inode = generic_delete_inode, 623 .show_options = bpf_show_options, 624 .free_inode = bpf_free_inode, 625 }; 626 627 enum { 628 OPT_MODE, 629 }; 630 631 static const struct fs_parameter_spec bpf_fs_parameters[] = { 632 fsparam_u32oct ("mode", OPT_MODE), 633 {} 634 }; 635 636 struct bpf_mount_opts { 637 umode_t mode; 638 }; 639 640 static int bpf_parse_param(struct fs_context *fc, struct fs_parameter *param) 641 { 642 struct bpf_mount_opts *opts = fc->fs_private; 643 struct fs_parse_result result; 644 int opt; 645 646 opt = fs_parse(fc, bpf_fs_parameters, param, &result); 647 if (opt < 0) { 648 /* We might like to report bad mount options here, but 649 * traditionally we've ignored all mount options, so we'd 650 * better continue to ignore non-existing options for bpf. 651 */ 652 if (opt == -ENOPARAM) { 653 opt = vfs_parse_fs_param_source(fc, param); 654 if (opt != -ENOPARAM) 655 return opt; 656 657 return 0; 658 } 659 660 if (opt < 0) 661 return opt; 662 } 663 664 switch (opt) { 665 case OPT_MODE: 666 opts->mode = result.uint_32 & S_IALLUGO; 667 break; 668 } 669 670 return 0; 671 } 672 673 struct bpf_preload_ops *bpf_preload_ops; 674 EXPORT_SYMBOL_GPL(bpf_preload_ops); 675 676 static bool bpf_preload_mod_get(void) 677 { 678 /* If bpf_preload.ko wasn't loaded earlier then load it now. 679 * When bpf_preload is built into vmlinux the module's __init 680 * function will populate it. 681 */ 682 if (!bpf_preload_ops) { 683 request_module("bpf_preload"); 684 if (!bpf_preload_ops) 685 return false; 686 } 687 /* And grab the reference, so the module doesn't disappear while the 688 * kernel is interacting with the kernel module and its UMD. 689 */ 690 if (!try_module_get(bpf_preload_ops->owner)) { 691 pr_err("bpf_preload module get failed.\n"); 692 return false; 693 } 694 return true; 695 } 696 697 static void bpf_preload_mod_put(void) 698 { 699 if (bpf_preload_ops) 700 /* now user can "rmmod bpf_preload" if necessary */ 701 module_put(bpf_preload_ops->owner); 702 } 703 704 static DEFINE_MUTEX(bpf_preload_lock); 705 706 static int populate_bpffs(struct dentry *parent) 707 { 708 struct bpf_preload_info objs[BPF_PRELOAD_LINKS] = {}; 709 int err = 0, i; 710 711 /* grab the mutex to make sure the kernel interactions with bpf_preload 712 * are serialized 713 */ 714 mutex_lock(&bpf_preload_lock); 715 716 /* if bpf_preload.ko wasn't built into vmlinux then load it */ 717 if (!bpf_preload_mod_get()) 718 goto out; 719 720 err = bpf_preload_ops->preload(objs); 721 if (err) 722 goto out_put; 723 for (i = 0; i < BPF_PRELOAD_LINKS; i++) { 724 bpf_link_inc(objs[i].link); 725 err = bpf_iter_link_pin_kernel(parent, 726 objs[i].link_name, objs[i].link); 727 if (err) { 728 bpf_link_put(objs[i].link); 729 goto out_put; 730 } 731 } 732 out_put: 733 bpf_preload_mod_put(); 734 out: 735 mutex_unlock(&bpf_preload_lock); 736 return err; 737 } 738 739 static int bpf_fill_super(struct super_block *sb, struct fs_context *fc) 740 { 741 static const struct tree_descr bpf_rfiles[] = { { "" } }; 742 struct bpf_mount_opts *opts = fc->fs_private; 743 struct inode *inode; 744 int ret; 745 746 ret = simple_fill_super(sb, BPF_FS_MAGIC, bpf_rfiles); 747 if (ret) 748 return ret; 749 750 sb->s_op = &bpf_super_ops; 751 752 inode = sb->s_root->d_inode; 753 inode->i_op = &bpf_dir_iops; 754 inode->i_mode &= ~S_IALLUGO; 755 populate_bpffs(sb->s_root); 756 inode->i_mode |= S_ISVTX | opts->mode; 757 return 0; 758 } 759 760 static int bpf_get_tree(struct fs_context *fc) 761 { 762 return get_tree_nodev(fc, bpf_fill_super); 763 } 764 765 static void bpf_free_fc(struct fs_context *fc) 766 { 767 kfree(fc->fs_private); 768 } 769 770 static const struct fs_context_operations bpf_context_ops = { 771 .free = bpf_free_fc, 772 .parse_param = bpf_parse_param, 773 .get_tree = bpf_get_tree, 774 }; 775 776 /* 777 * Set up the filesystem mount context. 778 */ 779 static int bpf_init_fs_context(struct fs_context *fc) 780 { 781 struct bpf_mount_opts *opts; 782 783 opts = kzalloc(sizeof(struct bpf_mount_opts), GFP_KERNEL); 784 if (!opts) 785 return -ENOMEM; 786 787 opts->mode = S_IRWXUGO; 788 789 fc->fs_private = opts; 790 fc->ops = &bpf_context_ops; 791 return 0; 792 } 793 794 static struct file_system_type bpf_fs_type = { 795 .owner = THIS_MODULE, 796 .name = "bpf", 797 .init_fs_context = bpf_init_fs_context, 798 .parameters = bpf_fs_parameters, 799 .kill_sb = kill_litter_super, 800 }; 801 802 static int __init bpf_init(void) 803 { 804 int ret; 805 806 ret = sysfs_create_mount_point(fs_kobj, "bpf"); 807 if (ret) 808 return ret; 809 810 ret = register_filesystem(&bpf_fs_type); 811 if (ret) 812 sysfs_remove_mount_point(fs_kobj, "bpf"); 813 814 return ret; 815 } 816 fs_initcall(bpf_init); 817