Release 4.10 fs/jffs2/compr_zlib.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * 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


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.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(MAX_WBITS,
							MAX_MEM_LEVEL));
	if (!def_strm.workspace)
		return -ENOMEM;

	jffs2_dbg(1, "Allocated %d bytes for deflate workspace\n",
		  zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL));
	inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
	if (!inf_strm.workspace) {
		vfree(def_strm.workspace);
		return -ENOMEM;
	}
	jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
		  zlib_inflate_workspacesize());
	return 0;
}

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static void free_workspaces(void)
{
	vfree(def_strm.workspace);
	vfree(inf_strm.workspace);
}
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#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)
{
	int ret;

	if (*dstlen <= STREAM_END_SPACE)
		return -1;

	mutex_lock(&deflate_mutex);

	if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
		pr_warn("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_t(unsigned long,
			(*sourcelen-def_strm.total_in), def_strm.avail_out);
		jffs2_dbg(1, "calling deflate with avail_in %ld, avail_out %ld\n",
			  def_strm.avail_in, def_strm.avail_out);
		ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
		jffs2_dbg(1, "deflate returned with avail_in %ld, avail_out %ld, 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) {
			jffs2_dbg(1, "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) {
		jffs2_dbg(1, "final deflate returned %d\n", ret);
		ret = -1;
		goto out;
	}

	if (def_strm.total_out >= def_strm.total_in) {
		jffs2_dbg(1, "zlib compressed %ld bytes into %ld; failing\n",
			  def_strm.total_in, def_strm.total_out);
		ret = -1;
		goto out;
	}

	jffs2_dbg(1, "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;
}

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joe perches
19
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2
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ingo molnar
8
2.23%
1
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yinghai lu
7
1.96%
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adrian bunk
adrian bunk
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static int jffs2_zlib_decompress(unsigned char *data_in,
				 unsigned char *cpage_out,
				 uint32_t srclen, uint32_t destlen)
{
	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)) {

		jffs2_dbg(2, "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 */
		jffs2_dbg(1, "inflate not skipping adler32\n");
	}


	if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
		pr_warn("inflateInit failed\n");
		mutex_unlock(&inflate_mutex);
		return 1;
	}

	while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
		;
	if (ret != Z_STREAM_END) {
		pr_notice("inflate returned %d\n", ret);
	}
	zlib_inflateEnd(&inf_strm);
	mutex_unlock(&inflate_mutex);
	return 0;
}

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3.25%
2
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ingo molnar
ingo molnar
6
2.44%
1
10.00%
adrian bunk
adrian bunk
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0.41%
1
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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;
}

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void jffs2_zlib_exit(void)
{
    jffs2_unregister_compressor(&jffs2_zlib_comp);
    free_workspaces();
}
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linus torvalds
322
35.08%
2
12.50%
joe perches
joe perches
40
4.36%
3
18.75%
ingo molnar
ingo molnar
21
2.29%
1
6.25%
james keniston
james keniston
10
1.09%
1
6.25%
yinghai lu
yinghai lu
7
0.76%
1
6.25%
thomas gleixner
thomas gleixner
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Directory: fs/jffs2

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