get_previous_size_availability() should have only one parameter in comments.

private-include/block_header.h

@@ -135,8 +135,6 @@ size_t get_previous_size(void *ptr);
  * space) 
  *
  * \param ptr 	The pointer to the data part of the previous memory block.
- * \param previous_size_availability The size for the data part of the previous
- * memory block on data layout level.
  */
 size_t get_previous_size_availability(void *ptr);