summaryrefslogtreecommitdiffstats
path: root/fs/squashfs/zstd_wrapper.c
blob: b448c2a1d0ed3540c0c7dc78bd4c8fef2c99c858 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Squashfs - a compressed read only filesystem for Linux
 *
 * Copyright (c) 2016-present, Facebook, Inc.
 * All rights reserved.
 *
 * zstd_wrapper.c
 */

#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/zstd.h>
#include <linux/vmalloc.h>

#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
#include "page_actor.h"

struct workspace {
	void *mem;
	size_t mem_size;
	size_t window_size;
};

static void *zstd_init(struct squashfs_sb_info *msblk, void *buff)
{
	struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL);

	if (wksp == NULL)
		goto failed;
	wksp->window_size = max_t(size_t,
			msblk->block_size, SQUASHFS_METADATA_SIZE);
	wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size);
	wksp->mem = vmalloc(wksp->mem_size);
	if (wksp->mem == NULL)
		goto failed;

	return wksp;

failed:
	ERROR("Failed to allocate zstd workspace\n");
	kfree(wksp);
	return ERR_PTR(-ENOMEM);
}


static void zstd_free(void *strm)
{
	struct workspace *wksp = strm;

	if (wksp)
		vfree(wksp->mem);
	kfree(wksp);
}


static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
	struct buffer_head **bh, int b, int offset, int length,
	struct squashfs_page_actor *output)
{
	struct workspace *wksp = strm;
	ZSTD_DStream *stream;
	size_t total_out = 0;
	size_t zstd_err;
	int k = 0;
	ZSTD_inBuffer in_buf = { NULL, 0, 0 };
	ZSTD_outBuffer out_buf = { NULL, 0, 0 };

	stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size);

	if (!stream) {
		ERROR("Failed to initialize zstd decompressor\n");
		goto out;
	}

	out_buf.size = PAGE_SIZE;
	out_buf.dst = squashfs_first_page(output);

	do {
		if (in_buf.pos == in_buf.size && k < b) {
			int avail = min(length, msblk->devblksize - offset);

			length -= avail;
			in_buf.src = bh[k]->b_data + offset;
			in_buf.size = avail;
			in_buf.pos = 0;
			offset = 0;
		}

		if (out_buf.pos == out_buf.size) {
			out_buf.dst = squashfs_next_page(output);
			if (out_buf.dst == NULL) {
				/* Shouldn't run out of pages
				 * before stream is done.
				 */
				squashfs_finish_page(output);
				goto out;
			}
			out_buf.pos = 0;
			out_buf.size = PAGE_SIZE;
		}

		total_out -= out_buf.pos;
		zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf);
		total_out += out_buf.pos; /* add the additional data produced */

		if (in_buf.pos == in_buf.size && k < b)
			put_bh(bh[k++]);
	} while (zstd_err != 0 && !ZSTD_isError(zstd_err));

	squashfs_finish_page(output);

	if (ZSTD_isError(zstd_err)) {
		ERROR("zstd decompression error: %d\n",
				(int)ZSTD_getErrorCode(zstd_err));
		goto out;
	}

	if (k < b)
		goto out;

	return (int)total_out;

out:
	for (; k < b; k++)
		put_bh(bh[k]);

	return -EIO;
}

const struct squashfs_decompressor squashfs_zstd_comp_ops = {
	.init = zstd_init,
	.free = zstd_free,
	.decompress = zstd_uncompress,
	.id = ZSTD_COMPRESSION,
	.name = "zstd",
	.supported = 1
};