compr.c
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/*
* fs/logfs/compr.c - compression routines
*
* As should be obvious for Linux kernel code, license is GPLv2
*
* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
*/
#include "logfs.h"
#include <linux/vmalloc.h>
#include <linux/zlib.h>
#define COMPR_LEVEL 3
static DEFINE_MUTEX(compr_mutex);
static struct z_stream_s stream;
int logfs_compress(void *in, void *out, size_t inlen, size_t outlen)
{
int err, ret;
ret = -EIO;
mutex_lock(&compr_mutex);
err = zlib_deflateInit(&stream, COMPR_LEVEL);
if (err != Z_OK)
goto error;
stream.next_in = in;
stream.avail_in = inlen;
stream.total_in = 0;
stream.next_out = out;
stream.avail_out = outlen;
stream.total_out = 0;
err = zlib_deflate(&stream, Z_FINISH);
if (err != Z_STREAM_END)
goto error;
err = zlib_deflateEnd(&stream);
if (err != Z_OK)
goto error;
if (stream.total_out >= stream.total_in)
goto error;
ret = stream.total_out;
error:
mutex_unlock(&compr_mutex);
return ret;
}
int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen)
{
int err, ret;
ret = -EIO;
mutex_lock(&compr_mutex);
err = zlib_inflateInit(&stream);
if (err != Z_OK)
goto error;
stream.next_in = in;
stream.avail_in = inlen;
stream.total_in = 0;
stream.next_out = out;
stream.avail_out = outlen;
stream.total_out = 0;
err = zlib_inflate(&stream, Z_FINISH);
if (err != Z_STREAM_END)
goto error;
err = zlib_inflateEnd(&stream);
if (err != Z_OK)
goto error;
ret = 0;
error:
mutex_unlock(&compr_mutex);
return ret;
}
int __init logfs_compr_init(void)
{
size_t size = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
zlib_inflate_workspacesize());
stream.workspace = vmalloc(size);
if (!stream.workspace)
return -ENOMEM;
return 0;
}
void logfs_compr_exit(void)
{
vfree(stream.workspace);
}