Update dfi_s390.c to support reading of compressed dump segments.
For this, introduce a callback function for reading memory chunks
associated with compressed dump segments. Apart from the segment location
on disk this function requires the entry_offset array from the dump segment
header in order to process each compressed entry separately, thus allowing
fast seek processing for zgetdump (no need to decompress a big dump segment
to extract a single piece of data).
In addition, split mem_chunks_add_ext() in several functions.
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>