LXR linux/fs/squashfs/decompressor

   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
  24struct squashfs_stream {
  25        void            *stream;
  26        struct mutex    mutex;
  27};
  28
  29void *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
  49out:
  50        kfree(stream);
  51        return ERR_PTR(err);
  52}
  53
  54void 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
  64int 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
  82int squashfs_max_decompressors(void)
  83{
  84        return 1;
  85}
  86