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kernel/linux-imx6_3.14.28/fs/jffs2/compr_lzo.c 2.2 KB
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  /*
   * JFFS2 -- Journalling Flash File System, Version 2.
   *
   * Copyright © 2007 Nokia Corporation. All rights reserved.
   * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
   *
   * 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/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);	/* for lzo_mem and lzo_compress_buf */
  
  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) {
  		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)
  {
  	size_t compress_size;
  	int ret;
  
  	mutex_lock(&deflate_mutex);
  	ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
  	if (ret != LZO_E_OK)
  		goto fail;
  
  	if (compress_size > *dstlen)
  		goto fail;
  
  	memcpy(cpage_out, lzo_compress_buf, compress_size);
  	mutex_unlock(&deflate_mutex);
  
  	*dstlen = compress_size;
  	return 0;
  
   fail:
  	mutex_unlock(&deflate_mutex);
  	return -1;
  }
  
  static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
  				 uint32_t srclen, uint32_t destlen)
  {
  	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();
  }