[Lzip-bug] Lzip patch for linux 5.10.25 released

[Antonio Diaz Diaz]

I am pleased to announce the release of the lzip patch for linux 5.10.25.

Since 2016 I maintain a patch adding lzip decompression support to the linux 
kernel. This includes support for lzip-compressed kernel image, initramfs, 
initrd, modules, and squashfs filesystems. The patch implements a linux 
module named lzip_decompress.

Decompression time is usually a small fraction of the total boot time. 
Therefore it is not worth using a faster but weaker algorithm just to save a 
fraction of a second from a total boot time of, say, 20 seconds.

Lzip related components in the kernel
=====================================

The lzip_decompress module in lib/lzip_decompress.c provides a versatile 
lzip decompression function able to do buffer to buffer decompression or 
stream decompression with fill and flush callback functions. The usage of 
the function is documented in include/linux/lzip.h.

For decompressing the kernel image, initramfs, and initrd, there is a 
wrapper function in lib/decompress_lunzip.c providing the same common 
interface as the other decompress_*.c files, which is defined in 
include/linux/decompress/generic.h.

For kernel makefiles, two commands are provided in scripts/Makefile.lib for 
use with $(call if_changed). The kernel image must be compressed with $(call 
if_changed,klzip) which will append a four-byte trailer containing the size 
of the uncompressed data, which is needed by the boot code. Other things 
should be compressed with $(call if_changed,lzip).

Testing
=======

Xlunzip is a test tool for the lzip_decompress module. It is similar to 
lunzip, but it uses the lzip_decompress module as a backend. The xlunzip 
tarball contains a copy of the lzip_decompress module and can be compiled 
and tested without downloading or applying the patch to the kernel. The 
homepage of xlunzip is at http://www.nongnu.org/lzip/xlunzip.html

The patch can be downloaded from
http://download.savannah.gnu.org/releases/lzip/kernel/linux-5.10.25_lzip-1.diff.lz

The sha256sum is:
c0e76e054adad5bb82a30d72ddaad9e785fdeb8ea4945f1c8e1630da1a9ee004 
linux-5.10.25_lzip-1.diff.lz

Please, test it and report any bugs you find.


Thanks,
Antonio Diaz, lzip author and maintainer.

--
If you care about data safety and long-term archiving, please consider using 
lzip. See http://www.nongnu.org/lzip/lzip_benchmark.html
http://www.nongnu.org/lzip/manual/lzip_manual.html#Quality-assurance and
http://www.nongnu.org/lzip/safety_of_the_lzip_format.html Thanks.