Re: [PATCH 1/5] fs: squashfs: port lzo compression support from kernel

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, Oct 04, 2016 at 12:10:44PM +0200, Enrico Jorns wrote:
> This ports lzo_wrapper from kernel code and adds some minimal adaptions
> to make squashfs lzo compression work in barebox.
> 
> Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
> ---
>  fs/squashfs/Kconfig       |  14 +++++
>  fs/squashfs/Makefile      |   1 +
>  fs/squashfs/lzo_wrapper.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/lzo.h       |  47 +++++++++++++++++
>  4 files changed, 190 insertions(+)
>  create mode 100644 fs/squashfs/lzo_wrapper.c
>  create mode 100644 include/linux/lzo.h
> 
> diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
> index dc25d93..d8ee554 100644
> --- a/fs/squashfs/Kconfig
> +++ b/fs/squashfs/Kconfig
> @@ -17,6 +17,20 @@ menuconfig FS_SQUASHFS
>  	  embedded systems where low overhead is needed.  Further information
>  	  and tools are available from http://squashfs.sourceforge.net.
>  
> +config SQUASHFS_LZO
> +	bool "Include support for LZO compressed file systems"
> +	default y
> +	depends on FS_SQUASHFS
> +	select LZO_DECOMPRESS
> +	help
> +	  Saying Y here includes support for reading Squashfs file systems
> +	  compressed with LZO compression.  LZO compression is mainly
> +	  aimed at embedded systems with slower CPUs where the overheads
> +	  of zlib are too high.
> +
> +	  LZO is not the standard compression used in Squashfs and so most
> +	  file systems will be readable without selecting this option.
> +
>  config SQUASHFS_XZ
>  	bool "Include support for XZ compressed file systems"
>  	default y
> diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
> index c0d024c..447e15e 100644
> --- a/fs/squashfs/Makefile
> +++ b/fs/squashfs/Makefile
> @@ -11,3 +11,4 @@ obj-y	+= inode.o
>  obj-y	+= namei.o
>  obj-y	+= super.o
>  obj-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
> +obj-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
> diff --git a/fs/squashfs/lzo_wrapper.c b/fs/squashfs/lzo_wrapper.c
> new file mode 100644
> index 0000000..b457955
> --- /dev/null
> +++ b/fs/squashfs/lzo_wrapper.c
> @@ -0,0 +1,128 @@
> +/*
> + * Squashfs - a compressed read only filesystem for Linux
> + *
> + * Copyright (c) 2010 LG Electronics
> + * Chan Jeong <chan.jeong@lge.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2,
> + * or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
> + *
> + * lzo_wrapper.c
> + */
> +
> +#include <linux/mutex.h>
> +#include <linux/lzo.h>
> +#include <types.h>
> +
> +#include "squashfs_fs.h"
> +#include "squashfs_fs_sb.h"
> +#include "squashfs.h"
> +#include "decompressor.h"
> +#include "page_actor.h"
> +
> +struct squashfs_lzo {
> +	void	*input;
> +	void	*output;
> +};
> +
> +static void *lzo_init(struct squashfs_sb_info *msblk, void *buff)
> +{
> +	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
> +
> +	struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
> +	if (stream == NULL)
> +		goto failed;
> +	stream->input = vmalloc(block_size);
> +	if (stream->input == NULL)
> +		goto failed;
> +	stream->output = vmalloc(block_size);
> +	if (stream->output == NULL)
> +		goto failed2;
> +
> +	return stream;
> +
> +failed2:
> +	vfree(stream->input);
> +failed:
> +	ERROR("Failed to allocate lzo workspace\n");
> +	kfree(stream);
> +	return ERR_PTR(-ENOMEM);
> +}
> +
> +
> +static void lzo_free(void *strm)
> +{
> +	struct squashfs_lzo *stream = strm;
> +
> +	if (stream) {
> +		vfree(stream->input);
> +		vfree(stream->output);
> +	}
> +	kfree(stream);
> +}
> +
> +
> +static int lzo_uncompress(struct squashfs_sb_info *msblk, void *strm,
> +	char **bh, int b, int offset, int length,
> +	struct squashfs_page_actor *output)
> +{
> +	struct squashfs_lzo *stream = strm;
> +	void *buff = stream->input, *data;
> +	int avail, i, bytes = length, res;
> +	size_t out_len = output->length;
> +
> +	for (i = 0; i < b; i++) {
> +		avail = min(bytes, msblk->devblksize - offset);
> +		memcpy(buff, bh[i] + offset, avail);
> +		buff += avail;
> +		bytes -= avail;
> +		offset = 0;
> +		kfree(bh[i]);
> +	}
> +
> +	res = lzo1x_decompress_safe(stream->input, (size_t)length,
> +					stream->output, &out_len);
> +	if (res != LZO_E_OK)
> +		goto failed;
> +
> +	res = bytes = (int)out_len;
> +	data = squashfs_first_page(output);
> +	buff = stream->output;
> +	while (data) {
> +		if (bytes <= PAGE_CACHE_SIZE) {
> +			memcpy(data, buff, bytes);
> +			break;
> +		} else {
> +			memcpy(data, buff, PAGE_CACHE_SIZE);
> +			buff += PAGE_CACHE_SIZE;
> +			bytes -= PAGE_CACHE_SIZE;
> +			data = squashfs_next_page(output);
> +		}
> +	}
> +	squashfs_finish_page(output);
> +
> +	return res;
> +
> +failed:
> +	return -EIO;
> +}
> +
> +const struct squashfs_decompressor squashfs_lzo_comp_ops = {
> +	.init = lzo_init,
> +	.free = lzo_free,
> +	.decompress = lzo_uncompress,
> +	.id = LZO_COMPRESSION,
> +	.name = "lzo",
> +	.supported = 1
> +};
> diff --git a/include/linux/lzo.h b/include/linux/lzo.h

We already have include/lzo.h with the same content, no need to add it
again.

Sascha

-- 
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