decompressor: Add LZ4 decompressor module

Date	Tue, 26 Feb 2013 15:24:27 +0900

This patch adds support for LZ4 decompression in the Linux Kernel.
LZ4 Decompression APIs for kernel are based on LZ4 implementation
by Yann Collet.

LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
LZ4 source repository : http://code.google.com/p/lz4/

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>

v2:
- Clean up code
- Enable unaligned access for ARM v6 and above with
  CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
- Add lz4_decompress() for faster decompression with
  uncompressed output size

Signed-off-by: Paul Reioux <reioux@gmail.com>
lib: Add support for LZ4-compressed kernel

Date	Tue, 26 Feb 2013 15:24:28 +0900

This patch adds support for extracting LZ4-compressed kernel images,
as well as LZ4-compressed ramdisk images in the kernel boot process.

This depends on the patch below
decompressor: Add LZ4 decompressor module

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>

v2:
- Clean up code
- Use lz4_decompress() for LZ4-compressed kernel during boot-process

Signed-off-by: Paul Reioux <reioux@gmail.com>
arm: Add support for LZ4-compressed kernel

Date	Tue, 26 Feb 2013 15:24:29 +0900

This patch integrates the LZ4 decompression code to the arm pre-boot code.
And it depends on two patchs below

lib: Add support for LZ4-compressed kernel
decompressor: Add LZ4 decompressor module

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>

v2:
- Apply CFLAGS, -Os to decompress.o to improve decompress
  performance during boot-up process

Signed-off-by: Paul Reioux <reioux@gmail.com>
lib: Add lz4 compressor module

From	Chanho Min <>

This patch adds support for LZ4 compression in the Linux Kernel.
LZ4 Compression APIs for kernel are based on LZ4 implementation
by Yann Collet and changed with kernel coding style.

LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
LZ4 source repository : http://code.google.com/p/lz4/
svn revision : r90

Two APIs are added:
lz4_compress() support basic lz4 compression whereas lz4hc_compress() support
high compression or CPU performance get lower but compression ratio get higher.
Also, we require the pre-allocated working memory with the defined size and
destination buffer must be allocated with the size of lz4_compressbound.

Signed-off-by: Chanho Min <chanho.min@lge.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>
crypto: Add lz4 Cryptographic API

From	Chanho Min <>

This patch adds support for lz4 and lz4hc compression algorithm
using the lib/lz4/* codebase.
Signed-off-by: Chanho Min <chanho.min@lge.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>
LZ4: compression/decompression signedness mismatch (v2)

LZ4 compression and decompression functions require different
in signedness input/output parameters: unsigned char for
compression and signed char for decompression.

Change decompression API to require "(const) unsigned char *".

v2: minor coding style fix.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

Signed-off-by: Paul Reioux <reioux@gmail.com>
zsmalloc: use PageFlag macro instead of [set|test]_bit

MM code always uses PageXXX to handle page flags.
Let's keep the consistency.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: rename zspage_order with zspage_pages

zspage_order defines how many pages are needed to make a zspage.
So _order_ is rather awkward naming. It already deceive Jonathan
- http://lwn.net/Articles/477067/
" For each size, the code calculates an optimum number of pages (up to 16)"

Let's change from _order_ to _pages_ and some function names.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: add/fix function comment

Add/fix the comment.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: zsmalloc: use unsigned long instead of void *

We should use unsigned long as handle instead of void * to avoid any
confusion. Without this, users may just treat zs_malloc return value as
a pointer and try to deference it.

This patch passed compile test(zram, zcache and ramster) and zram is
tested on qemu.

changelog
  * from v2
	- remove hval pointed out by Nitin
	- based on next-20120607
  * from v1
	- change zcache's zv_create return value
	- baesd on next-20120604

Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc documentation

Documentation of various struct page fields
used by zsmalloc.

Changes for v2:
	- Regroup descriptions as suggested by Konrad

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: fix uninit'ed variable warning

This patch fixes an uninitialized variable warning in
alloc_zspage().  It also fixes the secondary issue of
prev_page leaving scope on each loop iteration.  The only
reason this ever worked was because prev_page was occupying
the same space on the stack on each iteration.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: Finish conversion to a separate module

ZSMALLOC is tristate, but the code has no MODULE_LICENSE and since it
depends on GPL-only symbols it cannot be loaded as a module.  This in
turn breaks zram which now depends on it.  I assume it's meant to be
Dual BSD/GPL like the other z-stuff.

There is also no module_exit, which will make it impossible to unload.
Add the appropriate module_init and module_exit declarations suggested
by comments.

Reported-by: Christian Ohm <chr.ohm@gmx.net>
References: http://bugs.debian.org/677273
Cc: stable@vger.kernel.org # v3.4
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: remove x86 dependency

This patch replaces the page table assisted object mapping
method, which has x86 dependencies, with a arch-independent
method that does a simple copy into a temporary per-cpu
buffer.

While a copy seems like it would be worse than mapping the pages,
tests demonstrate the copying is always faster and, in the case of
running inside a KVM guest, roughly 4x faster.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: add single-page object fastpath in unmap

Improve zs_unmap_object() performance by adding a fast path for
objects that don't span pages.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: add details to zs_map_object boiler plate

Add information on the usage limits of zs_map_object()

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: prevent mappping in interrupt context

Because we use per-cpu mapping areas shared among the
pools/users, we can't allow mapping in interrupt context
because it can corrupt another users mappings.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zram: fix random data read

fd1a30de makes a bug that it uses (struct page *) as zsmalloc's handle
although it's a uncompressed page so that it can access random page,
return random data or even crashed by get_first_page in zs_map_object.

Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zram: remove special handle of uncompressed page

xvmalloc can't handle PAGE_SIZE page so that zram have to
handle it specially but zsmalloc can do it so let's remove
unnecessary special handling code.

Quote from Nitin
"I think page vs handle distinction was added since xvmalloc could not
handle full page allocation. Now that zsmalloc allows full page
allocation, we can just use it for both cases. This would also allow
removing the ZRAM_UNCOMPRESSED flag. The only downside will be slightly
slower code path for full page allocation but this event is anyways
supposed to be rare, so should be fine."

1. This patch reduces code very much.

 drivers/staging/zram/zram_drv.c   |  104 +++++--------------------------------
 drivers/staging/zram/zram_drv.h   |   17 +-----
 drivers/staging/zram/zram_sysfs.c |    6 +--
 3 files changed, 15 insertions(+), 112 deletions(-)

2. change pages_expand with bad_compress so it can count
   bad compression(above 75%) ratio.

3. remove zobj_header which is for back-reference for defragmentation
   because firstly, it's not used at the moment and zsmalloc can't handle
   bigger size than PAGE_SIZE so zram can't do it any more without redesign.

Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zram: conventions pr_warning -> pr_warn()

Porting zram to use the pr_warn() function instead of the deprecated
pr_warning().

Signed-off-by: Sam Hansen <solid.se7en@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>