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DEFINITIONS
This source file includes following definitions.
- alloc_workspaces
- free_workspaces
- jffs2_zlib_compress
- jffs2_zlib_decompress
- jffs2_zlib_init
- jffs2_zlib_exit
/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#if !defined(__KERNEL__) && !defined(__ECOS)
#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
#endif
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/zlib.h>
#include <linux/zutil.h>
#include "nodelist.h"
#include "compr.h"
/* Plan: call deflate() with avail_in == *sourcelen,
avail_out = *dstlen - 12 and flush == Z_FINISH.
If it doesn't manage to finish, call it again with
avail_in == 0 and avail_out set to the remaining 12
bytes for it to clean up.
Q: Is 12 bytes sufficient?
*/
#define STREAM_END_SPACE 12
static DEFINE_MUTEX(deflate_mutex);
static DEFINE_MUTEX(inflate_mutex);
static z_stream inf_strm, def_strm;
#ifdef __KERNEL__ /* Linux-only */
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/mutex.h>
static int __init alloc_workspaces(void)
{
def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
if (!def_strm.workspace) {
printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
return -ENOMEM;
}
D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
if (!inf_strm.workspace) {
printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
vfree(def_strm.workspace);
return -ENOMEM;
}
D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
return 0;
}
static void free_workspaces(void)
{
vfree(def_strm.workspace);
vfree(inf_strm.workspace);
}
#else
#define alloc_workspaces() (0)
#define free_workspaces() do { } while(0)
#endif /* __KERNEL__ */
static int jffs2_zlib_compress(unsigned char *data_in,
unsigned char *cpage_out,
uint32_t *sourcelen, uint32_t *dstlen,
void *model)
{
int ret;
if (*dstlen <= STREAM_END_SPACE)
return -1;
mutex_lock(&deflate_mutex);
if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
printk(KERN_WARNING "deflateInit failed\n");
mutex_unlock(&deflate_mutex);
return -1;
}
def_strm.next_in = data_in;
def_strm.total_in = 0;
def_strm.next_out = cpage_out;
def_strm.total_out = 0;
while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
def_strm.avail_in, def_strm.avail_out));
ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
if (ret != Z_OK) {
D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
zlib_deflateEnd(&def_strm);
mutex_unlock(&deflate_mutex);
return -1;
}
}
def_strm.avail_out += STREAM_END_SPACE;
def_strm.avail_in = 0;
ret = zlib_deflate(&def_strm, Z_FINISH);
zlib_deflateEnd(&def_strm);
if (ret != Z_STREAM_END) {
D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
ret = -1;
goto out;
}
if (def_strm.total_out >= def_strm.total_in) {
D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
def_strm.total_in, def_strm.total_out));
ret = -1;
goto out;
}
D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
def_strm.total_in, def_strm.total_out));
*dstlen = def_strm.total_out;
*sourcelen = def_strm.total_in;
ret = 0;
out:
mutex_unlock(&deflate_mutex);
return ret;
}
static int jffs2_zlib_decompress(unsigned char *data_in,
unsigned char *cpage_out,
uint32_t srclen, uint32_t destlen,
void *model)
{
int ret;
int wbits = MAX_WBITS;
mutex_lock(&inflate_mutex);
inf_strm.next_in = data_in;
inf_strm.avail_in = srclen;
inf_strm.total_in = 0;
inf_strm.next_out = cpage_out;
inf_strm.avail_out = destlen;
inf_strm.total_out = 0;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
wbits = -((data_in[0] >> 4) + 8);
inf_strm.next_in += 2;
inf_strm.avail_in -= 2;
} else {
/* Let this remain D1 for now -- it should never happen */
D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
}
if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
printk(KERN_WARNING "inflateInit failed\n");
mutex_unlock(&inflate_mutex);
return 1;
}
while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
;
if (ret != Z_STREAM_END) {
printk(KERN_NOTICE "inflate returned %d\n", ret);
}
zlib_inflateEnd(&inf_strm);
mutex_unlock(&inflate_mutex);
return 0;
}
static struct jffs2_compressor jffs2_zlib_comp = {
.priority = JFFS2_ZLIB_PRIORITY,
.name = "zlib",
.compr = JFFS2_COMPR_ZLIB,
.compress = &jffs2_zlib_compress,
.decompress = &jffs2_zlib_decompress,
#ifdef JFFS2_ZLIB_DISABLED
.disabled = 1,
#else
.disabled = 0,
#endif
};
int __init jffs2_zlib_init(void)
{
int ret;
ret = alloc_workspaces();
if (ret)
return ret;
ret = jffs2_register_compressor(&jffs2_zlib_comp);
if (ret)
free_workspaces();
return ret;
}
void jffs2_zlib_exit(void)
{
jffs2_unregister_compressor(&jffs2_zlib_comp);
free_workspaces();
}