/* * 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);}