static void cifs_extend_writeback(struct address_space *mapping,
				  long *_count,
				  loff_t start,
				  int max_pages,
				  size_t max_len,
				  unsigned int *_len)
static void cifs_extend_writeback(struct address_space *mapping,
				  struct xa_state *xas,
				  long *_count,
				  loff_t start,
				  int max_pages,
				  loff_t max_len,
				  size_t *_len)