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 };
92