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.h"
  33 #include "decompressor.h"
  34
  35 struct squashfs_lzo {
  36         void    *input;
  37         void    *output;
  38 };
  39
  40 static void *lzo_init(struct squashfs_sb_info *msblk)
  41 {
  42         int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
  43
  44         struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
  45         if (stream == NULL)
  46                 goto failed;
  47         stream->input = vmalloc(block_size);
  48         if (stream->input == NULL)
  49                 goto failed;
  50         stream->output = vmalloc(block_size);
  51         if (stream->output == NULL)
  52                 goto failed2;
  53
  54         return stream;
  55
  56 failed2:
  57         vfree(stream->input);
  58 failed:
  59         ERROR("Failed to allocate lzo workspace\n");
  60         kfree(stream);
  61         return NULL;
  62 }
  63
  64
  65 static void lzo_free(void *strm)
  66 {
  67         struct squashfs_lzo *stream = strm;
  68
  69         if (stream) {
  70                 vfree(stream->input);
  71                 vfree(stream->output);
  72         }
  73         kfree(stream);
  74 }
  75
  76
  77 static int lzo_uncompress(struct squashfs_sb_info *msblk, void **buffer,
  78         struct buffer_head **bh, int b, int offset, int length, int srclength,
  79         int pages)
  80 {
  81         struct squashfs_lzo *stream = msblk->stream;
  82         void *buff = stream->input;
  83         int avail, i, bytes = length, res;
  84         size_t out_len = srclength;
  85
  86         mutex_lock(&msblk->read_data_mutex);
  87
  88         for (i = 0; i < b; i++) {
  89                 wait_on_buffer(bh[i]);
  90                 if (!buffer_uptodate(bh[i]))
  91                         goto block_release;
  92
  93                 avail = min(bytes, msblk->devblksize - offset);
  94                 memcpy(buff, bh[i]->b_data + offset, avail);
  95                 buff += avail;
  96                 bytes -= avail;
  97                 offset = 0;
  98                 put_bh(bh[i]);
  99         }
 100
 101         res = lzo1x_decompress_safe(stream->input, (size_t)length,
 102                                         stream->output, &out_len);
 103         if (res != LZO_E_OK)
 104                 goto failed;
 105
 106         res = bytes = (int)out_len;
 107         for (i = 0, buff = stream->output; bytes && i < pages; i++) {
 108                 avail = min_t(int, bytes, PAGE_CACHE_SIZE);
 109                 memcpy(buffer[i], buff, avail);
 110                 buff += avail;
 111                 bytes -= avail;
 112         }
 113
 114         mutex_unlock(&msblk->read_data_mutex);
 115         return res;
 116
 117 block_release:
 118         for (; i < b; i++)
 119                 put_bh(bh[i]);
 120
 121 failed:
 122         mutex_unlock(&msblk->read_data_mutex);
 123
 124         ERROR("lzo decompression failed, data probably corrupt\n");
 125         return -EIO;
 126 }
 127
 128 const struct squashfs_decompressor squashfs_lzo_comp_ops = {
 129         .init = lzo_init,
 130         .free = lzo_free,
 131         .decompress = lzo_uncompress,
 132         .id = LZO_COMPRESSION,
 133         .name = "lzo",
 134         .supported = 1
 135 };