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/fs/squashfs/lzo_wrapper.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 135 lines | 91 code | 22 blank | 22 comment | 14 complexity | 703288263c85b93d253ccdfe3cb5cba8 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  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};