1/*
2 * Squashfs - a compressed read only filesystem for Linux
3 *
4 * Copyright (c) 2010 LG Electronics
5 * Chan Jeong <chan.jeong@lge.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2,
10 * or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 *
21 * lzo_wrapper.c
22 */
23
24#include <linux/mutex.h>
25#include <linux/buffer_head.h>
26#include <linux/slab.h>
27#include <linux/vmalloc.h>
28#include <linux/lzo.h>
29
30#include "squashfs_fs.h"
31#include "squashfs_fs_sb.h"
32#include "squashfs.h"
33#include "decompressor.h"
34
35struct squashfs_lzo {
36	void	*input;
37	void	*output;
38};
39
40static void *lzo_init(struct squashfs_sb_info *msblk, void *buff, int len)
41{
42	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
43
44	struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
45	if (stream == NULL)
46		goto failed;
47	stream->input = vmalloc(block_size);
48	if (stream->input == NULL)
49		goto failed;
50	stream->output = vmalloc(block_size);
51	if (stream->output == NULL)
52		goto failed2;
53
54	return stream;
55
56failed2:
57	vfree(stream->input);
58failed:
59	ERROR("Failed to allocate lzo workspace\n");
60	kfree(stream);
61	return ERR_PTR(-ENOMEM);
62}
63
64
65static void lzo_free(void *strm)
66{
67	struct squashfs_lzo *stream = strm;
68
69	if (stream) {
70		vfree(stream->input);
71		vfree(stream->output);
72	}
73	kfree(stream);
74}
75
76
77static int lzo_uncompress(struct squashfs_sb_info *msblk, void **buffer,
78	struct buffer_head **bh, int b, int offset, int length, int srclength,
79	int pages)
80{
81	struct squashfs_lzo *stream = msblk->stream;
82	void *buff = stream->input;
83	int avail, i, bytes = length, res;
84	size_t out_len = srclength;
85
86	mutex_lock(&msblk->read_data_mutex);
87
88	for (i = 0; i < b; i++) {
89		wait_on_buffer(bh[i]);
90		if (!buffer_uptodate(bh[i]))
91			goto block_release;
92
93		avail = min(bytes, msblk->devblksize - offset);
94		memcpy(buff, bh[i]->b_data + offset, avail);
95		buff += avail;
96		bytes -= avail;
97		offset = 0;
98		put_bh(bh[i]);
99	}
100
101	res = lzo1x_decompress_safe(stream->input, (size_t)length,
102					stream->output, &out_len);
103	if (res != LZO_E_OK)
104		goto failed;
105
106	res = bytes = (int)out_len;
107	for (i = 0, buff = stream->output; bytes && i < pages; i++) {
108		avail = min_t(int, bytes, PAGE_CACHE_SIZE);
109		memcpy(buffer[i], buff, avail);
110		buff += avail;
111		bytes -= avail;
112	}
113
114	mutex_unlock(&msblk->read_data_mutex);
115	return res;
116
117block_release:
118	for (; i < b; i++)
119		put_bh(bh[i]);
120
121failed:
122	mutex_unlock(&msblk->read_data_mutex);
123
124	ERROR("lzo decompression failed, data probably corrupt\n");
125	return -EIO;
126}
127
128const struct squashfs_decompressor squashfs_lzo_comp_ops = {
129	.init = lzo_init,
130	.free = lzo_free,
131	.decompress = lzo_uncompress,
132	.id = LZO_COMPRESSION,
133	.name = "lzo",
134	.supported = 1
135};
136