fs/squashfs/decompressor_single.c

   1 /*
   2  * Copyright (c) 2013
   3  * Phillip Lougher <phillip@squashfs.org.uk>
   4  *
   5  * This work is licensed under the terms of the GNU GPL, version 2. See
   6  * the COPYING file in the top-level directory.
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/mutex.h>
  11 #include <linux/slab.h>
  12 #include <linux/buffer_head.h>
  13
  14 #include "squashfs_fs.h"
  15 #include "squashfs_fs_sb.h"
  16 #include "decompressor.h"
  17 #include "squashfs.h"
  18
  19 /*
  20  * This file implements single-threaded decompression in the
  21  * decompressor framework
  22  */
  23
  24 struct squashfs_stream {
  25         void            *stream;
  26         struct mutex    mutex;
  27 };
  28
  29 void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
  30                                                 void *comp_opts)
  31 {
  32         struct squashfs_stream *stream;
  33         int err = -ENOMEM;
  34
  35         stream = kmalloc(sizeof(*stream), GFP_KERNEL);
  36         if (stream == NULL)
  37                 goto out;
  38
  39         stream->stream = msblk->decompressor->init(msblk, comp_opts);
  40         if (IS_ERR(stream->stream)) {
  41                 err = PTR_ERR(stream->stream);
  42                 goto out;
  43         }
  44
  45         kfree(comp_opts);
  46         mutex_init(&stream->mutex);
  47         return stream;
  48
  49 out:
  50         kfree(stream);
  51         return ERR_PTR(err);
  52 }
  53
  54 void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
  55 {
  56         struct squashfs_stream *stream = msblk->stream;
  57
  58         if (stream) {
  59                 msblk->decompressor->free(stream->stream);
  60                 kfree(stream);
  61         }
  62 }
  63
  64 int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
  65         int b, int offset, int length, struct squashfs_page_actor *output)
  66 {
  67         int res;
  68         struct squashfs_stream *stream = msblk->stream;
  69
  70         mutex_lock(&stream->mutex);
  71         res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
  72                 offset, length, output);
  73         mutex_unlock(&stream->mutex);
  74
  75         if (res < 0)
  76                 ERROR("%s decompression failed, data probably corrupt\n",
  77                         msblk->decompressor->name);
  78
  79         return res;
  80 }
  81
  82 int squashfs_max_decompressors(void)
  83 {
  84         return 1;
  85 }