fs/debugfs/inode.c

   1 /*
   2  *  inode.c - part of debugfs, a tiny little debug file system
   3  *
   4  *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   5  *  Copyright (C) 2004 IBM Inc.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License version
   9  *      2 as published by the Free Software Foundation.
  10  *
  11  *  debugfs is for people to use instead of /proc or /sys.
  12  *  See Documentation/DocBook/kernel-api for more details.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/fs.h>
  18 #include <linux/mount.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/init.h>
  21 #include <linux/kobject.h>
  22 #include <linux/namei.h>
  23 #include <linux/debugfs.h>
  24 #include <linux/fsnotify.h>
  25 #include <linux/string.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/parser.h>
  28 #include <linux/magic.h>
  29 #include <linux/slab.h>
  30
  31 #define DEBUGFS_DEFAULT_MODE    0700
  32
  33 static struct vfsmount *debugfs_mount;
  34 static int debugfs_mount_count;
  35 static bool debugfs_registered;
  36
  37 static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev,
  38                                        void *data, const struct file_operations *fops)
  39
  40 {
  41         struct inode *inode = new_inode(sb);
  42
  43         if (inode) {
  44                 inode->i_ino = get_next_ino();
  45                 inode->i_mode = mode;
  46                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  47                 switch (mode & S_IFMT) {
  48                 default:
  49                         init_special_inode(inode, mode, dev);
  50                         break;
  51                 case S_IFREG:
  52                         inode->i_fop = fops ? fops : &debugfs_file_operations;
  53                         inode->i_private = data;
  54                         break;
  55                 case S_IFLNK:
  56                         inode->i_op = &debugfs_link_operations;
  57                         inode->i_private = data;
  58                         break;
  59                 case S_IFDIR:
  60                         inode->i_op = &simple_dir_inode_operations;
  61                         inode->i_fop = &simple_dir_operations;
  62
  63                         /* directory inodes start off with i_nlink == 2
  64                          * (for "." entry) */
  65                         inc_nlink(inode);
  66                         break;
  67                 }
  68         }
  69         return inode;
  70 }
  71
  72 /* SMP-safe */
  73 static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
  74                          umode_t mode, dev_t dev, void *data,
  75                          const struct file_operations *fops)
  76 {
  77         struct inode *inode;
  78         int error = -EPERM;
  79
  80         if (dentry->d_inode)
  81                 return -EEXIST;
  82
  83         inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
  84         if (inode) {
  85                 d_instantiate(dentry, inode);
  86                 dget(dentry);
  87                 error = 0;
  88         }
  89         return error;
  90 }
  91
  92 static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
  93 {
  94         int res;
  95
  96         mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
  97         res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL);
  98         if (!res) {
  99                 inc_nlink(dir);
 100                 fsnotify_mkdir(dir, dentry);
 101         }
 102         return res;
 103 }
 104
 105 static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,
 106                         void *data)
 107 {
 108         mode = (mode & S_IALLUGO) | S_IFLNK;
 109         return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
 110 }
 111
 112 static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 113                           void *data, const struct file_operations *fops)
 114 {
 115         int res;
 116
 117         mode = (mode & S_IALLUGO) | S_IFREG;
 118         res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
 119         if (!res)
 120                 fsnotify_create(dir, dentry);
 121         return res;
 122 }
 123
 124 static inline int debugfs_positive(struct dentry *dentry)
 125 {
 126         return dentry->d_inode && !d_unhashed(dentry);
 127 }
 128
 129 struct debugfs_mount_opts {
 130         kuid_t uid;
 131         kgid_t gid;
 132         umode_t mode;
 133 };
 134
 135 enum {
 136         Opt_uid,
 137         Opt_gid,
 138         Opt_mode,
 139         Opt_err
 140 };
 141
 142 static const match_table_t tokens = {
 143         {Opt_uid, "uid=%u"},
 144         {Opt_gid, "gid=%u"},
 145         {Opt_mode, "mode=%o"},
 146         {Opt_err, NULL}
 147 };
 148
 149 struct debugfs_fs_info {
 150         struct debugfs_mount_opts mount_opts;
 151 };
 152
 153 static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
 154 {
 155         substring_t args[MAX_OPT_ARGS];
 156         int option;
 157         int token;
 158         kuid_t uid;
 159         kgid_t gid;
 160         char *p;
 161
 162         opts->mode = DEBUGFS_DEFAULT_MODE;
 163
 164         while ((p = strsep(&data, ",")) != NULL) {
 165                 if (!*p)
 166                         continue;
 167
 168                 token = match_token(p, tokens, args);
 169                 switch (token) {
 170                 case Opt_uid:
 171                         if (match_int(&args[0], &option))
 172                                 return -EINVAL;
 173                         uid = make_kuid(current_user_ns(), option);
 174                         if (!uid_valid(uid))
 175                                 return -EINVAL;
 176                         opts->uid = uid;
 177                         break;
 178                 case Opt_gid:
 179                         if (match_int(&args[0], &option))
 180                                 return -EINVAL;
 181                         gid = make_kgid(current_user_ns(), option);
 182                         if (!gid_valid(gid))
 183                                 return -EINVAL;
 184                         opts->gid = gid;
 185                         break;
 186                 case Opt_mode:
 187                         if (match_octal(&args[0], &option))
 188                                 return -EINVAL;
 189                         opts->mode = option & S_IALLUGO;
 190                         break;
 191                 /*
 192                  * We might like to report bad mount options here;
 193                  * but traditionally debugfs has ignored all mount options
 194                  */
 195                 }
 196         }
 197
 198         return 0;
 199 }
 200
 201 static int debugfs_apply_options(struct super_block *sb)
 202 {
 203         struct debugfs_fs_info *fsi = sb->s_fs_info;
 204         struct inode *inode = sb->s_root->d_inode;
 205         struct debugfs_mount_opts *opts = &fsi->mount_opts;
 206
 207         inode->i_mode &= ~S_IALLUGO;
 208         inode->i_mode |= opts->mode;
 209
 210         inode->i_uid = opts->uid;
 211         inode->i_gid = opts->gid;
 212
 213         return 0;
 214 }
 215
 216 static int debugfs_remount(struct super_block *sb, int *flags, char *data)
 217 {
 218         int err;
 219         struct debugfs_fs_info *fsi = sb->s_fs_info;
 220
 221         sync_filesystem(sb);
 222         err = debugfs_parse_options(data, &fsi->mount_opts);
 223         if (err)
 224                 goto fail;
 225
 226         debugfs_apply_options(sb);
 227
 228 fail:
 229         return err;
 230 }
 231
 232 static int debugfs_show_options(struct seq_file *m, struct dentry *root)
 233 {
 234         struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
 235         struct debugfs_mount_opts *opts = &fsi->mount_opts;
 236
 237         if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
 238                 seq_printf(m, ",uid=%u",
 239                            from_kuid_munged(&init_user_ns, opts->uid));
 240         if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
 241                 seq_printf(m, ",gid=%u",
 242                            from_kgid_munged(&init_user_ns, opts->gid));
 243         if (opts->mode != DEBUGFS_DEFAULT_MODE)
 244                 seq_printf(m, ",mode=%o", opts->mode);
 245
 246         return 0;
 247 }
 248
 249 static const struct super_operations debugfs_super_operations = {
 250         .statfs         = simple_statfs,
 251         .remount_fs     = debugfs_remount,
 252         .show_options   = debugfs_show_options,
 253 };
 254
 255 static int debug_fill_super(struct super_block *sb, void *data, int silent)
 256 {
 257         static struct tree_descr debug_files[] = {{""}};
 258         struct debugfs_fs_info *fsi;
 259         int err;
 260
 261         save_mount_options(sb, data);
 262
 263         fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
 264         sb->s_fs_info = fsi;
 265         if (!fsi) {
 266                 err = -ENOMEM;
 267                 goto fail;
 268         }
 269
 270         err = debugfs_parse_options(data, &fsi->mount_opts);
 271         if (err)
 272                 goto fail;
 273
 274         err  =  simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
 275         if (err)
 276                 goto fail;
 277
 278         sb->s_op = &debugfs_super_operations;
 279
 280         debugfs_apply_options(sb);
 281
 282         return 0;
 283
 284 fail:
 285         kfree(fsi);
 286         sb->s_fs_info = NULL;
 287         return err;
 288 }
 289
 290 static struct dentry *debug_mount(struct file_system_type *fs_type,
 291                         int flags, const char *dev_name,
 292                         void *data)
 293 {
 294         return mount_single(fs_type, flags, data, debug_fill_super);
 295 }
 296
 297 static struct file_system_type debug_fs_type = {
 298         .owner =        THIS_MODULE,
 299         .name =         "debugfs",
 300         .mount =        debug_mount,
 301         .kill_sb =      kill_litter_super,
 302 };
 303 MODULE_ALIAS_FS("debugfs");
 304
 305 static struct dentry *__create_file(const char *name, umode_t mode,
 306                                     struct dentry *parent, void *data,
 307                                     const struct file_operations *fops)
 308 {
 309         struct dentry *dentry = NULL;
 310         int error;
 311
 312         pr_debug("debugfs: creating file '%s'\n",name);
 313
 314         error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
 315                               &debugfs_mount_count);
 316         if (error)
 317                 goto exit;
 318
 319         /* If the parent is not specified, we create it in the root.
 320          * We need the root dentry to do this, which is in the super
 321          * block. A pointer to that is in the struct vfsmount that we
 322          * have around.
 323          */
 324         if (!parent)
 325                 parent = debugfs_mount->mnt_root;
 326
 327         mutex_lock(&parent->d_inode->i_mutex);
 328         dentry = lookup_one_len(name, parent, strlen(name));
 329         if (!IS_ERR(dentry)) {
 330                 switch (mode & S_IFMT) {
 331                 case S_IFDIR:
 332                         error = debugfs_mkdir(parent->d_inode, dentry, mode);
 333
 334                         break;
 335                 case S_IFLNK:
 336                         error = debugfs_link(parent->d_inode, dentry, mode,
 337                                              data);
 338                         break;
 339                 default:
 340                         error = debugfs_create(parent->d_inode, dentry, mode,
 341                                                data, fops);
 342                         break;
 343                 }
 344                 dput(dentry);
 345         } else
 346                 error = PTR_ERR(dentry);
 347         mutex_unlock(&parent->d_inode->i_mutex);
 348
 349         if (error) {
 350                 dentry = NULL;
 351                 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 352         }
 353 exit:
 354         return dentry;
 355 }
 356
 357 /**
 358  * debugfs_create_file - create a file in the debugfs filesystem
 359  * @name: a pointer to a string containing the name of the file to create.
 360  * @mode: the permission that the file should have.
 361  * @parent: a pointer to the parent dentry for this file.  This should be a
 362  *          directory dentry if set.  If this parameter is NULL, then the
 363  *          file will be created in the root of the debugfs filesystem.
 364  * @data: a pointer to something that the caller will want to get to later
 365  *        on.  The inode.i_private pointer will point to this value on
 366  *        the open() call.
 367  * @fops: a pointer to a struct file_operations that should be used for
 368  *        this file.
 369  *
 370  * This is the basic "create a file" function for debugfs.  It allows for a
 371  * wide range of flexibility in creating a file, or a directory (if you want
 372  * to create a directory, the debugfs_create_dir() function is
 373  * recommended to be used instead.)
 374  *
 375  * This function will return a pointer to a dentry if it succeeds.  This
 376  * pointer must be passed to the debugfs_remove() function when the file is
 377  * to be removed (no automatic cleanup happens if your module is unloaded,
 378  * you are responsible here.)  If an error occurs, %NULL will be returned.
 379  *
 380  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 381  * returned.
 382  */
 383 struct dentry *debugfs_create_file(const char *name, umode_t mode,
 384                                    struct dentry *parent, void *data,
 385                                    const struct file_operations *fops)
 386 {
 387         switch (mode & S_IFMT) {
 388         case S_IFREG:
 389         case 0:
 390                 break;
 391         default:
 392                 BUG();
 393         }
 394
 395         return __create_file(name, mode, parent, data, fops);
 396 }
 397 EXPORT_SYMBOL_GPL(debugfs_create_file);
 398
 399 /**
 400  * debugfs_create_dir - create a directory in the debugfs filesystem
 401  * @name: a pointer to a string containing the name of the directory to
 402  *        create.
 403  * @parent: a pointer to the parent dentry for this file.  This should be a
 404  *          directory dentry if set.  If this parameter is NULL, then the
 405  *          directory will be created in the root of the debugfs filesystem.
 406  *
 407  * This function creates a directory in debugfs with the given name.
 408  *
 409  * This function will return a pointer to a dentry if it succeeds.  This
 410  * pointer must be passed to the debugfs_remove() function when the file is
 411  * to be removed (no automatic cleanup happens if your module is unloaded,
 412  * you are responsible here.)  If an error occurs, %NULL will be returned.
 413  *
 414  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 415  * returned.
 416  */
 417 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
 418 {
 419         return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
 420                                    parent, NULL, NULL);
 421 }
 422 EXPORT_SYMBOL_GPL(debugfs_create_dir);
 423
 424 /**
 425  * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
 426  * @name: a pointer to a string containing the name of the symbolic link to
 427  *        create.
 428  * @parent: a pointer to the parent dentry for this symbolic link.  This
 429  *          should be a directory dentry if set.  If this parameter is NULL,
 430  *          then the symbolic link will be created in the root of the debugfs
 431  *          filesystem.
 432  * @target: a pointer to a string containing the path to the target of the
 433  *          symbolic link.
 434  *
 435  * This function creates a symbolic link with the given name in debugfs that
 436  * links to the given target path.
 437  *
 438  * This function will return a pointer to a dentry if it succeeds.  This
 439  * pointer must be passed to the debugfs_remove() function when the symbolic
 440  * link is to be removed (no automatic cleanup happens if your module is
 441  * unloaded, you are responsible here.)  If an error occurs, %NULL will be
 442  * returned.
 443  *
 444  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 445  * returned.
 446  */
 447 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
 448                                       const char *target)
 449 {
 450         struct dentry *result;
 451         char *link;
 452
 453         link = kstrdup(target, GFP_KERNEL);
 454         if (!link)
 455                 return NULL;
 456
 457         result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
 458         if (!result)
 459                 kfree(link);
 460         return result;
 461 }
 462 EXPORT_SYMBOL_GPL(debugfs_create_symlink);
 463
 464 static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
 465 {
 466         int ret = 0;
 467
 468         if (debugfs_positive(dentry)) {
 469                 if (dentry->d_inode) {
 470                         dget(dentry);
 471                         switch (dentry->d_inode->i_mode & S_IFMT) {
 472                         case S_IFDIR:
 473                                 ret = simple_rmdir(parent->d_inode, dentry);
 474                                 break;
 475                         case S_IFLNK:
 476                                 kfree(dentry->d_inode->i_private);
 477                                 /* fall through */
 478                         default:
 479                                 simple_unlink(parent->d_inode, dentry);
 480                                 break;
 481                         }
 482                         if (!ret)
 483                                 d_delete(dentry);
 484                         dput(dentry);
 485                 }
 486         }
 487         return ret;
 488 }
 489
 490 /**
 491  * debugfs_remove - removes a file or directory from the debugfs filesystem
 492  * @dentry: a pointer to a the dentry of the file or directory to be
 493  *          removed.
 494  *
 495  * This function removes a file or directory in debugfs that was previously
 496  * created with a call to another debugfs function (like
 497  * debugfs_create_file() or variants thereof.)
 498  *
 499  * This function is required to be called in order for the file to be
 500  * removed, no automatic cleanup of files will happen when a module is
 501  * removed, you are responsible here.
 502  */
 503 void debugfs_remove(struct dentry *dentry)
 504 {
 505         struct dentry *parent;
 506         int ret;
 507
 508         if (IS_ERR_OR_NULL(dentry))
 509                 return;
 510
 511         parent = dentry->d_parent;
 512         if (!parent || !parent->d_inode)
 513                 return;
 514
 515         mutex_lock(&parent->d_inode->i_mutex);
 516         ret = __debugfs_remove(dentry, parent);
 517         mutex_unlock(&parent->d_inode->i_mutex);
 518         if (!ret)
 519                 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 520 }
 521 EXPORT_SYMBOL_GPL(debugfs_remove);
 522
 523 /**
 524  * debugfs_remove_recursive - recursively removes a directory
 525  * @dentry: a pointer to a the dentry of the directory to be removed.
 526  *
 527  * This function recursively removes a directory tree in debugfs that
 528  * was previously created with a call to another debugfs function
 529  * (like debugfs_create_file() or variants thereof.)
 530  *
 531  * This function is required to be called in order for the file to be
 532  * removed, no automatic cleanup of files will happen when a module is
 533  * removed, you are responsible here.
 534  */
 535 void debugfs_remove_recursive(struct dentry *dentry)
 536 {
 537         struct dentry *child, *parent;
 538
 539         if (IS_ERR_OR_NULL(dentry))
 540                 return;
 541
 542         parent = dentry->d_parent;
 543         if (!parent || !parent->d_inode)
 544                 return;
 545
 546         parent = dentry;
 547  down:
 548         mutex_lock(&parent->d_inode->i_mutex);
 549  loop:
 550         /*
 551          * The parent->d_subdirs is protected by the d_lock. Outside that
 552          * lock, the child can be unlinked and set to be freed which can
 553          * use the d_u.d_child as the rcu head and corrupt this list.
 554          */
 555         spin_lock(&parent->d_lock);
 556         list_for_each_entry(child, &parent->d_subdirs, d_child) {
 557                 if (!debugfs_positive(child))
 558                         continue;
 559
 560                 /* perhaps simple_empty(child) makes more sense */
 561                 if (!list_empty(&child->d_subdirs)) {
 562                         spin_unlock(&parent->d_lock);
 563                         mutex_unlock(&parent->d_inode->i_mutex);
 564                         parent = child;
 565                         goto down;
 566                 }
 567
 568                 spin_unlock(&parent->d_lock);
 569
 570                 if (!__debugfs_remove(child, parent))
 571                         simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 572
 573                 /*
 574                  * The parent->d_lock protects agaist child from unlinking
 575                  * from d_subdirs. When releasing the parent->d_lock we can
 576                  * no longer trust that the next pointer is valid.
 577                  * Restart the loop. We'll skip this one with the
 578                  * debugfs_positive() check.
 579                  */
 580                 goto loop;
 581         }
 582         spin_unlock(&parent->d_lock);
 583
 584         mutex_unlock(&parent->d_inode->i_mutex);
 585         child = parent;
 586         parent = parent->d_parent;
 587         mutex_lock(&parent->d_inode->i_mutex);
 588
 589         if (child != dentry)
 590                 /* go up */
 591                 goto loop;
 592
 593         if (!__debugfs_remove(child, parent))
 594                 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
 595         mutex_unlock(&parent->d_inode->i_mutex);
 596 }
 597 EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
 598
 599 /**
 600  * debugfs_rename - rename a file/directory in the debugfs filesystem
 601  * @old_dir: a pointer to the parent dentry for the renamed object. This
 602  *          should be a directory dentry.
 603  * @old_dentry: dentry of an object to be renamed.
 604  * @new_dir: a pointer to the parent dentry where the object should be
 605  *          moved. This should be a directory dentry.
 606  * @new_name: a pointer to a string containing the target name.
 607  *
 608  * This function renames a file/directory in debugfs.  The target must not
 609  * exist for rename to succeed.
 610  *
 611  * This function will return a pointer to old_dentry (which is updated to
 612  * reflect renaming) if it succeeds. If an error occurs, %NULL will be
 613  * returned.
 614  *
 615  * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 616  * returned.
 617  */
 618 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 619                 struct dentry *new_dir, const char *new_name)
 620 {
 621         int error;
 622         struct dentry *dentry = NULL, *trap;
 623         const char *old_name;
 624
 625         trap = lock_rename(new_dir, old_dir);
 626         /* Source or destination directories don't exist? */
 627         if (!old_dir->d_inode || !new_dir->d_inode)
 628                 goto exit;
 629         /* Source does not exist, cyclic rename, or mountpoint? */
 630         if (!old_dentry->d_inode || old_dentry == trap ||
 631             d_mountpoint(old_dentry))
 632                 goto exit;
 633         dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
 634         /* Lookup failed, cyclic rename or target exists? */
 635         if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
 636                 goto exit;
 637
 638         old_name = fsnotify_oldname_init(old_dentry->d_name.name);
 639
 640         error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
 641                 dentry);
 642         if (error) {
 643                 fsnotify_oldname_free(old_name);
 644                 goto exit;
 645         }
 646         d_move(old_dentry, dentry);
 647         fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
 648                 S_ISDIR(old_dentry->d_inode->i_mode),
 649                 NULL, old_dentry);
 650         fsnotify_oldname_free(old_name);
 651         unlock_rename(new_dir, old_dir);
 652         dput(dentry);
 653         return old_dentry;
 654 exit:
 655         if (dentry && !IS_ERR(dentry))
 656                 dput(dentry);
 657         unlock_rename(new_dir, old_dir);
 658         return NULL;
 659 }
 660 EXPORT_SYMBOL_GPL(debugfs_rename);
 661
 662 /**
 663  * debugfs_initialized - Tells whether debugfs has been registered
 664  */
 665 bool debugfs_initialized(void)
 666 {
 667         return debugfs_registered;
 668 }
 669 EXPORT_SYMBOL_GPL(debugfs_initialized);
 670
 671
 672 static struct kobject *debug_kobj;
 673
 674 static int __init debugfs_init(void)
 675 {
 676         int retval;
 677
 678         debug_kobj = kobject_create_and_add("debug", kernel_kobj);
 679         if (!debug_kobj)
 680                 return -EINVAL;
 681
 682         retval = register_filesystem(&debug_fs_type);
 683         if (retval)
 684                 kobject_put(debug_kobj);
 685         else
 686                 debugfs_registered = true;
 687
 688         return retval;
 689 }
 690 core_initcall(debugfs_init);
 691