1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (c) 2013, 2014
4*4882a593Smuzhiyun * Phillip Lougher <phillip@squashfs.org.uk>
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #include <linux/bio.h>
8*4882a593Smuzhiyun #include <linux/mutex.h>
9*4882a593Smuzhiyun #include <linux/slab.h>
10*4882a593Smuzhiyun #include <linux/vmalloc.h>
11*4882a593Smuzhiyun #include <linux/lz4.h>
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #include "squashfs_fs.h"
14*4882a593Smuzhiyun #include "squashfs_fs_sb.h"
15*4882a593Smuzhiyun #include "squashfs.h"
16*4882a593Smuzhiyun #include "decompressor.h"
17*4882a593Smuzhiyun #include "page_actor.h"
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #define LZ4_LEGACY 1
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun struct lz4_comp_opts {
22*4882a593Smuzhiyun __le32 version;
23*4882a593Smuzhiyun __le32 flags;
24*4882a593Smuzhiyun };
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun struct squashfs_lz4 {
27*4882a593Smuzhiyun void *input;
28*4882a593Smuzhiyun void *output;
29*4882a593Smuzhiyun };
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun
lz4_comp_opts(struct squashfs_sb_info * msblk,void * buff,int len)32*4882a593Smuzhiyun static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
33*4882a593Smuzhiyun void *buff, int len)
34*4882a593Smuzhiyun {
35*4882a593Smuzhiyun struct lz4_comp_opts *comp_opts = buff;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun /* LZ4 compressed filesystems always have compression options */
38*4882a593Smuzhiyun if (comp_opts == NULL || len < sizeof(*comp_opts))
39*4882a593Smuzhiyun return ERR_PTR(-EIO);
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
42*4882a593Smuzhiyun /* LZ4 format currently used by the kernel is the 'legacy'
43*4882a593Smuzhiyun * format */
44*4882a593Smuzhiyun ERROR("Unknown LZ4 version\n");
45*4882a593Smuzhiyun return ERR_PTR(-EINVAL);
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun return NULL;
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun
lz4_init(struct squashfs_sb_info * msblk,void * buff)52*4882a593Smuzhiyun static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
53*4882a593Smuzhiyun {
54*4882a593Smuzhiyun int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
55*4882a593Smuzhiyun struct squashfs_lz4 *stream;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun stream = kzalloc(sizeof(*stream), GFP_KERNEL);
58*4882a593Smuzhiyun if (stream == NULL)
59*4882a593Smuzhiyun goto failed;
60*4882a593Smuzhiyun stream->input = vmalloc(block_size);
61*4882a593Smuzhiyun if (stream->input == NULL)
62*4882a593Smuzhiyun goto failed2;
63*4882a593Smuzhiyun stream->output = vmalloc(block_size);
64*4882a593Smuzhiyun if (stream->output == NULL)
65*4882a593Smuzhiyun goto failed3;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun return stream;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun failed3:
70*4882a593Smuzhiyun vfree(stream->input);
71*4882a593Smuzhiyun failed2:
72*4882a593Smuzhiyun kfree(stream);
73*4882a593Smuzhiyun failed:
74*4882a593Smuzhiyun ERROR("Failed to initialise LZ4 decompressor\n");
75*4882a593Smuzhiyun return ERR_PTR(-ENOMEM);
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun
lz4_free(void * strm)79*4882a593Smuzhiyun static void lz4_free(void *strm)
80*4882a593Smuzhiyun {
81*4882a593Smuzhiyun struct squashfs_lz4 *stream = strm;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun if (stream) {
84*4882a593Smuzhiyun vfree(stream->input);
85*4882a593Smuzhiyun vfree(stream->output);
86*4882a593Smuzhiyun }
87*4882a593Smuzhiyun kfree(stream);
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun
lz4_uncompress(struct squashfs_sb_info * msblk,void * strm,struct bio * bio,int offset,int length,struct squashfs_page_actor * output)91*4882a593Smuzhiyun static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
92*4882a593Smuzhiyun struct bio *bio, int offset, int length,
93*4882a593Smuzhiyun struct squashfs_page_actor *output)
94*4882a593Smuzhiyun {
95*4882a593Smuzhiyun struct bvec_iter_all iter_all = {};
96*4882a593Smuzhiyun struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
97*4882a593Smuzhiyun struct squashfs_lz4 *stream = strm;
98*4882a593Smuzhiyun void *buff = stream->input, *data;
99*4882a593Smuzhiyun int bytes = length, res;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun while (bio_next_segment(bio, &iter_all)) {
102*4882a593Smuzhiyun int avail = min(bytes, ((int)bvec->bv_len) - offset);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun data = page_address(bvec->bv_page) + bvec->bv_offset;
105*4882a593Smuzhiyun memcpy(buff, data + offset, avail);
106*4882a593Smuzhiyun buff += avail;
107*4882a593Smuzhiyun bytes -= avail;
108*4882a593Smuzhiyun offset = 0;
109*4882a593Smuzhiyun }
110*4882a593Smuzhiyun
111*4882a593Smuzhiyun res = LZ4_decompress_safe(stream->input, stream->output,
112*4882a593Smuzhiyun length, output->length);
113*4882a593Smuzhiyun
114*4882a593Smuzhiyun if (res < 0)
115*4882a593Smuzhiyun return -EIO;
116*4882a593Smuzhiyun
117*4882a593Smuzhiyun bytes = res;
118*4882a593Smuzhiyun data = squashfs_first_page(output);
119*4882a593Smuzhiyun buff = stream->output;
120*4882a593Smuzhiyun while (data) {
121*4882a593Smuzhiyun if (bytes <= PAGE_SIZE) {
122*4882a593Smuzhiyun memcpy(data, buff, bytes);
123*4882a593Smuzhiyun break;
124*4882a593Smuzhiyun }
125*4882a593Smuzhiyun memcpy(data, buff, PAGE_SIZE);
126*4882a593Smuzhiyun buff += PAGE_SIZE;
127*4882a593Smuzhiyun bytes -= PAGE_SIZE;
128*4882a593Smuzhiyun data = squashfs_next_page(output);
129*4882a593Smuzhiyun }
130*4882a593Smuzhiyun squashfs_finish_page(output);
131*4882a593Smuzhiyun
132*4882a593Smuzhiyun return res;
133*4882a593Smuzhiyun }
134*4882a593Smuzhiyun
135*4882a593Smuzhiyun const struct squashfs_decompressor squashfs_lz4_comp_ops = {
136*4882a593Smuzhiyun .init = lz4_init,
137*4882a593Smuzhiyun .comp_opts = lz4_comp_opts,
138*4882a593Smuzhiyun .free = lz4_free,
139*4882a593Smuzhiyun .decompress = lz4_uncompress,
140*4882a593Smuzhiyun .id = LZ4_COMPRESSION,
141*4882a593Smuzhiyun .name = "lz4",
142*4882a593Smuzhiyun .supported = 1
143*4882a593Smuzhiyun };
144