decompress_bunzip2 and decompress_unlzma have a nasty hack that subtracts
4 from the input length if being called in the pre-boot environment.

This is a nasty hack because it relies on the fact that flush = NULL only
when called from the pre-boot environment (i.e.
arch/x86/boot/compressed/misc.c).  initramfs.c/do_mounts_rd.c pass in a
flush buffer (flush != NULL).

This hack prevents the decompressors from being used with flush = NULL by
other callers unless knowledge of the hack is propagated to them.

This patch removes the hack by making decompress (called only from the
pre-boot environment) a wrapper function that subtracts 4 from the input
length before calling the decompressor.
Signed-off-by: NPhillip Lougher <phillip@lougher.demon.co.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Impact: cleanup

lib/decompress_bunzip2.c depends on slab.h without including it:

    CC      lib/decompress_bunzip2.o
  lib/decompress_bunzip2.c: In function ‘start_bunzip’:
  lib/decompress_bunzip2.c:636: error: implicit declaration of function ‘kmalloc’
  lib/decompress_bunzip2.c:636: warning: assignment makes pointer from integer without a cast
  lib/decompress_bunzip2.c: In function ‘bunzip2’:
  lib/decompress_bunzip2.c:682: warning: assignment makes pointer from integer without a cast
  lib/decompress_bunzip2.c:693: warning: assignment makes pointer from integer without a cast
  lib/decompress_bunzip2.c:726: error: implicit declaration of function ‘kfree’
  make[1]: *** [lib/decompress_bunzip2.o] Error 1
  make: *** [lib/] Error 2

It gets included implicitly currently - but this will not be the
case with upcoming kmemtrace changes.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
LKML-Reference: <1237886032.25315.48.camel@penberg-laptop>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: Replaces inflate.c with a wrapper around zlib_inflate; new library code

This is the first part of the bzip2/lzma patch

The bzip patch is based on an idea by Christian Ludwig, includes support for
compressing the kernel with bzip2 or lzma rather than gzip. Both
compressors give smaller sizes than gzip.  Lzma's decompresses faster
than bzip2.

It also supports ramdisks and initramfs' compressed using these two
compressors.

The functionality has been successfully used for a couple of years by
the udpcast project

This version applies to "tip" kernel 2.6.28

This part contains:
- changed inflate.c to accomodate rest of patch
- implementation of bzip2 compression (not used at this stage yet)
- implementation of lzma compression (not used at this stage yet)
- Makefile routines to support bzip2 and lzma kernel compression
Signed-off-by: NAlain Knaff <alain@knaff.lu>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>