fs/squashfs/decompressor_single.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2013
   4  * Phillip Lougher <phillip@squashfs.org.uk>
   5  */
   6
   7 #include <linux/types.h>
   8 #include <linux/mutex.h>
   9 #include <linux/slab.h>
  10 #include <linux/bio.h>
  11
  12 #include "squashfs_fs.h"
  13 #include "squashfs_fs_sb.h"
  14 #include "decompressor.h"
  15 #include "squashfs.h"
  16
  17 /*
  18  * This file implements single-threaded decompression in the
  19  * decompressor framework
  20  */
  21
  22 struct squashfs_stream {
  23         void            *stream;
  24         struct mutex    mutex;
  25 };
  26
  27 static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
  28                                                 void *comp_opts)
  29 {
  30         struct squashfs_stream *stream;
  31         int err = -ENOMEM;
  32
  33         stream = kmalloc(sizeof(*stream), GFP_KERNEL);
  34         if (stream == NULL)
  35                 goto out;
  36
  37         stream->stream = msblk->decompressor->init(msblk, comp_opts);
  38         if (IS_ERR(stream->stream)) {
  39                 err = PTR_ERR(stream->stream);
  40                 goto out;
  41         }
  42
  43         kfree(comp_opts);
  44         mutex_init(&stream->mutex);
  45         return stream;
  46
  47 out:
  48         kfree(stream);
  49         return ERR_PTR(err);
  50 }
  51
  52 static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
  53 {
  54         struct squashfs_stream *stream = msblk->stream;
  55
  56         if (stream) {
  57                 msblk->decompressor->free(stream->stream);
  58                 kfree(stream);
  59         }
  60 }
  61
  62 static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
  63                         int offset, int length,
  64                         struct squashfs_page_actor *output)
  65 {
  66         int res;
  67         struct squashfs_stream *stream = msblk->stream;
  68
  69         mutex_lock(&stream->mutex);
  70         res = msblk->decompressor->decompress(msblk, stream->stream, bio,
  71                 offset, length, output);
  72         mutex_unlock(&stream->mutex);
  73
  74         if (res < 0)
  75                 ERROR("%s decompression failed, data probably corrupt\n",
  76                         msblk->decompressor->name);
  77
  78         return res;
  79 }
  80
  81 static int squashfs_max_decompressors(void)
  82 {
  83         return 1;
  84 }
  85
  86 const struct squashfs_decompressor_thread_ops squashfs_decompressor_single = {
  87         .create = squashfs_decompressor_create,
  88         .destroy = squashfs_decompressor_destroy,
  89         .decompress = squashfs_decompress,
  90         .max_decompressors = squashfs_max_decompressors,
  91 };