diff options
| -rw-r--r-- | fs/debugfs/inode.c | 36 | ||||
| -rw-r--r-- | include/linux/debugfs.h | 8 |
2 files changed, 44 insertions, 0 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index f17fcf89e18e..7fb1732a3630 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -248,6 +248,42 @@ static struct file_system_type debug_fs_type = { }; MODULE_ALIAS_FS("debugfs"); +/** + * debugfs_lookup() - look up an existing debugfs file + * @name: a pointer to a string containing the name of the file to look up. + * @parent: a pointer to the parent dentry of the file. + * + * This function will return a pointer to a dentry if it succeeds. If the file + * doesn't exist or an error occurs, %NULL will be returned. The returned + * dentry must be passed to dput() when it is no longer needed. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. + */ +struct dentry *debugfs_lookup(const char *name, struct dentry *parent) +{ + struct dentry *dentry; + + if (IS_ERR(parent)) + return NULL; + + if (!parent) + parent = debugfs_mount->mnt_root; + + inode_lock(d_inode(parent)); + dentry = lookup_one_len(name, parent, strlen(name)); + inode_unlock(d_inode(parent)); + + if (IS_ERR(dentry)) + return NULL; + if (!d_really_is_positive(dentry)) { + dput(dentry); + return NULL; + } + return dentry; +} +EXPORT_SYMBOL_GPL(debugfs_lookup); + static struct dentry *start_creating(const char *name, struct dentry *parent) { struct dentry *dentry; diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index 014cc564d1c4..c0befcf41b58 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -80,6 +80,8 @@ static const struct file_operations __fops = { \ #if defined(CONFIG_DEBUG_FS) +struct dentry *debugfs_lookup(const char *name, struct dentry *parent); + struct dentry *debugfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops); @@ -181,6 +183,12 @@ ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf, * want to duplicate the design decision mistakes of procfs and devfs again. */ +static inline struct dentry *debugfs_lookup(const char *name, + struct dentry *parent) +{ + return ERR_PTR(-ENODEV); +} + static inline struct dentry *debugfs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops) |