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

[Yegor Yefremov <yegorslists@googlemail.com>]

On Tue, Oct 4, 2016 at 9:34 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> 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>

Tested-by: Yegor Yefremov <yegorslists@googlemail.com>

>> ---
>>  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
>
> --
> Pengutronix e.K.                           |                             |
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>
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