fs/squashfs/lzo_wrapper.c

   1 /*
   2  * Squashfs - a compressed read only filesystem for Linux
   3  *
   4  * Copyright (c) 2010 LG Electronics
   5  * Chan Jeong <chan.jeong@lge.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2,
  10  * or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  *
  21  * lzo_wrapper.c
  22  */
  23
  24 #include <linux/mutex.h>
  25 #include <linux/buffer_head.h>
  26 #include <linux/slab.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/lzo.h>
  29
  30 #include "squashfs_fs.h"
  31 #include "squashfs_fs_sb.h"
  32 #include "squashfs_fs_i.h"
  33 #include "squashfs.h"
  34 #include "decompressor.h"
  35
  36 struct squashfs_lzo {
  37         void    *input;
  38         void    *output;
  39 };
  40
  41 static void *lzo_init(struct squashfs_sb_info *msblk)
  42 {
  43         int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
  44
  45         struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
  46         if (stream == NULL)
  47                 goto failed;
  48         stream->input = vmalloc(block_size);
  49         if (stream->input == NULL)
  50                 goto failed;
  51         stream->output = vmalloc(block_size);
  52         if (stream->output == NULL)
  53                 goto failed2;
  54
  55         return stream;
  56
  57 failed2:
  58         vfree(stream->input);
  59 failed:
  60         ERROR("Failed to allocate lzo workspace\n");
  61         kfree(stream);
  62         return NULL;
  63 }
  64
  65
  66 static void lzo_free(void *strm)
  67 {
  68         struct squashfs_lzo *stream = strm;
  69
  70         if (stream) {
  71                 vfree(stream->input);
  72                 vfree(stream->output);
  73         }
  74         kfree(stream);
  75 }
  76
  77
  78 static int lzo_uncompress(struct squashfs_sb_info *msblk, void **buffer,
  79         struct buffer_head **bh, int b, int offset, int length, int srclength,
  80         int pages)
  81 {
  82         struct squashfs_lzo *stream = msblk->stream;
  83         void *buff = stream->input;
  84         int avail, i, bytes = length, res;
  85         size_t out_len = srclength;
  86
  87         mutex_lock(&msblk->read_data_mutex);
  88
  89         for (i = 0; i < b; i++) {
  90                 wait_on_buffer(bh[i]);
  91                 if (!buffer_uptodate(bh[i]))
  92                         goto block_release;
  93
  94                 avail = min(bytes, msblk->devblksize - offset);
  95                 memcpy(buff, bh[i]->b_data + offset, avail);
  96                 buff += avail;
  97                 bytes -= avail;
  98                 offset = 0;
  99                 put_bh(bh[i]);
 100         }
 101
 102         res = lzo1x_decompress_safe(stream->input, (size_t)length,
 103                                         stream->output, &out_len);
 104         if (res != LZO_E_OK)
 105                 goto failed;
 106
 107         res = bytes = (int)out_len;
 108         for (i = 0, buff = stream->output; bytes && i < pages; i++) {
 109                 avail = min_t(int, bytes, PAGE_CACHE_SIZE);
 110                 memcpy(buffer[i], buff, avail);
 111                 buff += avail;
 112                 bytes -= avail;
 113         }
 114
 115         mutex_unlock(&msblk->read_data_mutex);
 116         return res;
 117
 118 block_release:
 119         for (; i < b; i++)
 120                 put_bh(bh[i]);
 121
 122 failed:
 123         mutex_unlock(&msblk->read_data_mutex);
 124
 125         ERROR("lzo decompression failed, data probably corrupt\n");
 126         return -EIO;
 127 }
 128
 129 const struct squashfs_decompressor squashfs_lzo_comp_ops = {
 130         .init = lzo_init,
 131         .free = lzo_free,
 132         .decompress = lzo_uncompress,
 133         .id = LZO_COMPRESSION,
 134         .name = "lzo",
 135         .supported = 1
 136 };