root/fs/jffs2/compr_lzo.c

DEFINITIONS

1. free_workspace
2. alloc_workspace
3. jffs2_lzo_compress
4. jffs2_lzo_decompress
5. jffs2_lzo_init
6. jffs2_lzo_exit

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2007 Nokia Corporation. All rights reserved.
 *
 * Created by Richard Purdie <rpurdie@openedhand.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/lzo.h>
#include "compr.h"

static void *lzo_mem;
static void *lzo_compress_buf;
static DEFINE_MUTEX(deflate_mutex);

static void free_workspace(void)
{
        vfree(lzo_mem);
        vfree(lzo_compress_buf);
}

static int __init alloc_workspace(void)
{
        lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
        lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));

        if (!lzo_mem || !lzo_compress_buf) {
                printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
                free_workspace();
                return -ENOMEM;
        }

        return 0;
}

static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
                              uint32_t *sourcelen, uint32_t *dstlen, void *model)
{
        size_t compress_size;
        int ret;

        mutex_lock(&deflate_mutex);
        ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
        mutex_unlock(&deflate_mutex);

        if (ret != LZO_E_OK)
                return -1;

        if (compress_size > *dstlen)
                return -1;

        memcpy(cpage_out, lzo_compress_buf, compress_size);
        *dstlen = compress_size;

        return 0;
}

static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
                                 uint32_t srclen, uint32_t destlen, void *model)
{
        size_t dl = destlen;
        int ret;

        ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl);

        if (ret != LZO_E_OK || dl != destlen)
                return -1;

        return 0;
}

static struct jffs2_compressor jffs2_lzo_comp = {
        .priority = JFFS2_LZO_PRIORITY,
        .name = "lzo",
        .compr = JFFS2_COMPR_LZO,
        .compress = &jffs2_lzo_compress,
        .decompress = &jffs2_lzo_decompress,
        .disabled = 0,
};

int __init jffs2_lzo_init(void)
{
        int ret;

        ret = alloc_workspace();
        if (ret < 0)
                return ret;

        ret = jffs2_register_compressor(&jffs2_lzo_comp);
        if (ret)
                free_workspace();

        return ret;
}

void jffs2_lzo_exit(void)
{
        jffs2_unregister_compressor(&jffs2_lzo_comp);
        free_workspace();
}