debugfs: update documented return values of debugfs helpers

Since commit ff9fb72bc077 ("debugfs: return error values, not NULL")
these helper functions do not return NULL anymore (with the exception
of debugfs_create_u32_array()).

Fixes: ff9fb72bc077 ("debugfs: return error values, not NULL")
Signed-off-by: Ronald Tschalär <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/filesystems/debugfs.txt

···
 indicated parent directory.  If parent is NULL, the directory will be
 created in the debugfs root.  On success, the return value is a struct
 dentry pointer which can be used to create files in the directory (and to
-clean it up at the end).  A NULL return value indicates that something went
-wrong.  If ERR_PTR(-ENODEV) is returned, that is an indication that the
-kernel has been built without debugfs support and none of the functions
-described below will work.
+clean it up at the end).  An ERR_PTR(-ERROR) return value indicates that
+something went wrong.  If ERR_PTR(-ENODEV) is returned, that is an
+indication that the kernel has been built without debugfs support and none
+of the functions described below will work.
 
 The most general way to create a file within a debugfs directory is with:
 
···
 resulting inode structure, and fops is a set of file operations which
 implement the file's behavior.  At a minimum, the read() and/or write()
 operations should be provided; others can be included as needed.  Again,
-the return value will be a dentry pointer to the created file, NULL for
-error, or ERR_PTR(-ENODEV) if debugfs support is missing.
+the return value will be a dentry pointer to the created file,
+ERR_PTR(-ERROR) on error, or ERR_PTR(-ENODEV) if debugfs support is
+missing.
 
 Create a file with an initial size, the following function can be used
 instead:
···
 
     void debugfs_remove(struct dentry *dentry);
 
-The dentry value can be NULL, in which case nothing will be removed.
+The dentry value can be NULL or an error value, in which case nothing will
+be removed.
 
 Once upon a time, debugfs users were required to remember the dentry
 pointer for every debugfs file they created so that all files could be

fs/debugfs/file.c

···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_u8(const char *name, umode_t mode,
 				 struct dentry *parent, u8 *value)
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 				  struct dentry *parent, u16 *value)
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 				 struct dentry *parent, u32 *value)
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 				 struct dentry *parent, u64 *value)
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
 				    struct dentry *parent, unsigned long *value)
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 				   struct dentry *parent, bool *value)
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 				   struct dentry *parent,
···
  * Writing is not supported. Seek within the file is also not supported.
  * Once array is created its size can not be changed.
  *
- * The function returns a pointer to dentry on success. If debugfs is not
- * enabled in the kernel, the value -%ENODEV will be returned.
+ * The function returns a pointer to dentry on success. If an error occurs,
+ * %ERR_PTR(-ERROR) or NULL will be returned. If debugfs is not enabled in
+ * the kernel, the value %ERR_PTR(-ENODEV) will be returned.
  */
 struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 					    struct dentry *parent,
···
  * This function will return a pointer to a dentry if it succeeds.  This
  * pointer must be passed to the debugfs_remove() function when the file is
  * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.)  If an error occurs, %NULL will be returned.
+ * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
+ * returned.
  *
- * If debugfs is not enabled in the kernel, the value -%ENODEV will be
- * returned.  It is not wise to check for this value, but rather, check for
- * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
- * code.
+ * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
+ * be returned.
  */
 struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
 				       struct dentry *parent,