fs/jffs2/compr_lzo.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright © 2007 Nokia Corporation. All rights reserved.
   5  *
   6  * Created by Richard Purdie <rpurdie@openedhand.com>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/slab.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);
  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         mutex_unlock(&deflate_mutex);
  53
  54         if (ret != LZO_E_OK)
  55                 return -1;
  56
  57         if (compress_size > *dstlen)
  58                 return -1;
  59
  60         memcpy(cpage_out, lzo_compress_buf, compress_size);
  61         *dstlen = compress_size;
  62
  63         return 0;
  64 }
  65
  66 static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
  67                                  uint32_t srclen, uint32_t destlen, void *model)
  68 {
  69         size_t dl = destlen;
  70         int ret;
  71
  72         ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl);
  73
  74         if (ret != LZO_E_OK || dl != destlen)
  75                 return -1;
  76
  77         return 0;
  78 }
  79
  80 static struct jffs2_compressor jffs2_lzo_comp = {
  81         .priority = JFFS2_LZO_PRIORITY,
  82         .name = "lzo",
  83         .compr = JFFS2_COMPR_LZO,
  84         .compress = &jffs2_lzo_compress,
  85         .decompress = &jffs2_lzo_decompress,
  86         .disabled = 0,
  87 };
  88
  89 int __init jffs2_lzo_init(void)
  90 {
  91         int ret;
  92
  93         ret = alloc_workspace();
  94         if (ret < 0)
  95                 return ret;
  96
  97         ret = jffs2_register_compressor(&jffs2_lzo_comp);
  98         if (ret)
  99                 free_workspace();
 100
 101         return ret;
 102 }
 103
 104 void jffs2_lzo_exit(void)
 105 {
 106         jffs2_unregister_compressor(&jffs2_lzo_comp);
 107         free_workspace();
 108 }