release/src-rt-6.x.4708/linux/linux-2.6.36/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                 printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
  37                 free_workspace();
  38                 return -ENOMEM;
  39         }
  40
  41         return 0;
  42 }
  43
  44 static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
  45                               uint32_t *sourcelen, uint32_t *dstlen, void *model)
  46 {
  47         size_t compress_size;
  48         int ret;
  49
  50         mutex_lock(&deflate_mutex);
  51         ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
  52         if (ret != LZO_E_OK)
  53                 goto fail;
  54
  55         if (compress_size > *dstlen)
  56                 goto fail;
  57
  58         memcpy(cpage_out, lzo_compress_buf, compress_size);
  59         mutex_unlock(&deflate_mutex);
  60
  61         *dstlen = compress_size;
  62         return 0;
  63
  64  fail:
  65         mutex_unlock(&deflate_mutex);
  66         return -1;
  67 }
  68
  69 static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
  70                                  uint32_t srclen, uint32_t destlen, void *model)
  71 {
  72         size_t dl = destlen;
  73         int ret;
  74
  75         ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl);
  76
  77         if (ret != LZO_E_OK || dl != destlen)
  78                 return -1;
  79
  80         return 0;
  81 }
  82
  83 static struct jffs2_compressor jffs2_lzo_comp = {
  84         .priority = JFFS2_LZO_PRIORITY,
  85         .name = "lzo",
  86         .compr = JFFS2_COMPR_LZO,
  87         .compress = &jffs2_lzo_compress,
  88         .decompress = &jffs2_lzo_decompress,
  89         .disabled = 0,
  90 };
  91
  92 int __init jffs2_lzo_init(void)
  93 {
  94         int ret;
  95
  96         ret = alloc_workspace();
  97         if (ret < 0)
  98                 return ret;
  99
 100         ret = jffs2_register_compressor(&jffs2_lzo_comp);
 101         if (ret)
 102                 free_workspace();
 103
 104         return ret;
 105 }
 106
 107 void jffs2_lzo_exit(void)
 108 {
 109         jffs2_unregister_compressor(&jffs2_lzo_comp);
 110         free_workspace();
 111 }