kernel/fs/jffs2/compr_lzo.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2007 Nokia Corporation. All rights reserved.
   5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
   6  *
   7  * Created by Richard Purdie <rpurdie@openedhand.com>
   8  *
   9  * For licensing information, see the file 'LICENCE' in this directory.
  10  *
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/init.h>
  17 #include <linux/lzo.h>
  18 #include "compr.h"
  19
  20 static void *lzo_mem;
  21 static void *lzo_compress_buf;
  22 static DEFINE_MUTEX(deflate_mutex);     /* for lzo_mem and lzo_compress_buf */
  23
  24 static void free_workspace(void)
  25 {
  26         vfree(lzo_mem);
  27         vfree(lzo_compress_buf);
  28 }
  29
  30 static int __init alloc_workspace(void)
  31 {
  32         lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
  33         lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
  34
  35         if (!lzo_mem || !lzo_compress_buf) {
  36                 free_workspace();
  37                 return -ENOMEM;
  38         }
  39
  40         return 0;
  41 }
  42
  43 static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
  44                               uint32_t *sourcelen, uint32_t *dstlen)
  45 {
  46         size_t compress_size;
  47         int ret;
  48
  49         mutex_lock(&deflate_mutex);
  50         ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
  51         if (ret != LZO_E_OK)
  52                 goto fail;
  53
  54         if (compress_size > *dstlen)
  55                 goto fail;
  56
  57         memcpy(cpage_out, lzo_compress_buf, compress_size);
  58         mutex_unlock(&deflate_mutex);
  59
  60         *dstlen = compress_size;
  61         return 0;
  62
  63  fail:
  64         mutex_unlock(&deflate_mutex);
  65         return -1;
  66 }
  67
  68 static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
  69                                  uint32_t srclen, uint32_t destlen)
  70 {
  71         size_t dl = destlen;
  72         int ret;
  73
  74         ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl);
  75
  76         if (ret != LZO_E_OK || dl != destlen)
  77                 return -1;
  78
  79         return 0;
  80 }
  81
  82 static struct jffs2_compressor jffs2_lzo_comp = {
  83         .priority = JFFS2_LZO_PRIORITY,
  84         .name = "lzo",
  85         .compr = JFFS2_COMPR_LZO,
  86         .compress = &jffs2_lzo_compress,
  87         .decompress = &jffs2_lzo_decompress,
  88         .disabled = 0,
  89 };
  90
  91 int __init jffs2_lzo_init(void)
  92 {
  93         int ret;
  94
  95         ret = alloc_workspace();
  96         if (ret < 0)
  97                 return ret;
  98
  99         ret = jffs2_register_compressor(&jffs2_lzo_comp);
 100         if (ret)
 101                 free_workspace();
 102
 103         return ret;
 104 }
 105
 106 void jffs2_lzo_exit(void)
 107 {
 108         jffs2_unregister_compressor(&jffs2_lzo_comp);
 109         free_workspace();
 110 }