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3e0a4e85 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
87bf54bb SP |
2 | /* |
3 | * Squashfs - a compressed read only filesystem for Linux | |
4 | * | |
5 | * Copyright (c) 2016-present, Facebook, Inc. | |
6 | * All rights reserved. | |
7 | * | |
87bf54bb SP |
8 | * zstd_wrapper.c |
9 | */ | |
10 | ||
11 | #include <linux/mutex.h> | |
12 | #include <linux/buffer_head.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/zstd.h> | |
15 | #include <linux/vmalloc.h> | |
16 | ||
17 | #include "squashfs_fs.h" | |
18 | #include "squashfs_fs_sb.h" | |
19 | #include "squashfs.h" | |
20 | #include "decompressor.h" | |
21 | #include "page_actor.h" | |
22 | ||
23 | struct workspace { | |
24 | void *mem; | |
25 | size_t mem_size; | |
26 | size_t window_size; | |
27 | }; | |
28 | ||
29 | static void *zstd_init(struct squashfs_sb_info *msblk, void *buff) | |
30 | { | |
31 | struct workspace *wksp = kmalloc(sizeof(*wksp), GFP_KERNEL); | |
32 | ||
33 | if (wksp == NULL) | |
34 | goto failed; | |
35 | wksp->window_size = max_t(size_t, | |
36 | msblk->block_size, SQUASHFS_METADATA_SIZE); | |
37 | wksp->mem_size = ZSTD_DStreamWorkspaceBound(wksp->window_size); | |
38 | wksp->mem = vmalloc(wksp->mem_size); | |
39 | if (wksp->mem == NULL) | |
40 | goto failed; | |
41 | ||
42 | return wksp; | |
43 | ||
44 | failed: | |
45 | ERROR("Failed to allocate zstd workspace\n"); | |
46 | kfree(wksp); | |
47 | return ERR_PTR(-ENOMEM); | |
48 | } | |
49 | ||
50 | ||
51 | static void zstd_free(void *strm) | |
52 | { | |
53 | struct workspace *wksp = strm; | |
54 | ||
55 | if (wksp) | |
56 | vfree(wksp->mem); | |
57 | kfree(wksp); | |
58 | } | |
59 | ||
60 | ||
61 | static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm, | |
62 | struct buffer_head **bh, int b, int offset, int length, | |
63 | struct squashfs_page_actor *output) | |
64 | { | |
65 | struct workspace *wksp = strm; | |
66 | ZSTD_DStream *stream; | |
67 | size_t total_out = 0; | |
68 | size_t zstd_err; | |
69 | int k = 0; | |
70 | ZSTD_inBuffer in_buf = { NULL, 0, 0 }; | |
71 | ZSTD_outBuffer out_buf = { NULL, 0, 0 }; | |
72 | ||
73 | stream = ZSTD_initDStream(wksp->window_size, wksp->mem, wksp->mem_size); | |
74 | ||
75 | if (!stream) { | |
76 | ERROR("Failed to initialize zstd decompressor\n"); | |
77 | goto out; | |
78 | } | |
79 | ||
80 | out_buf.size = PAGE_SIZE; | |
81 | out_buf.dst = squashfs_first_page(output); | |
82 | ||
83 | do { | |
84 | if (in_buf.pos == in_buf.size && k < b) { | |
85 | int avail = min(length, msblk->devblksize - offset); | |
86 | ||
87 | length -= avail; | |
88 | in_buf.src = bh[k]->b_data + offset; | |
89 | in_buf.size = avail; | |
90 | in_buf.pos = 0; | |
91 | offset = 0; | |
92 | } | |
93 | ||
94 | if (out_buf.pos == out_buf.size) { | |
95 | out_buf.dst = squashfs_next_page(output); | |
96 | if (out_buf.dst == NULL) { | |
97 | /* Shouldn't run out of pages | |
98 | * before stream is done. | |
99 | */ | |
100 | squashfs_finish_page(output); | |
101 | goto out; | |
102 | } | |
103 | out_buf.pos = 0; | |
104 | out_buf.size = PAGE_SIZE; | |
105 | } | |
106 | ||
107 | total_out -= out_buf.pos; | |
108 | zstd_err = ZSTD_decompressStream(stream, &out_buf, &in_buf); | |
109 | total_out += out_buf.pos; /* add the additional data produced */ | |
110 | ||
111 | if (in_buf.pos == in_buf.size && k < b) | |
112 | put_bh(bh[k++]); | |
113 | } while (zstd_err != 0 && !ZSTD_isError(zstd_err)); | |
114 | ||
115 | squashfs_finish_page(output); | |
116 | ||
117 | if (ZSTD_isError(zstd_err)) { | |
118 | ERROR("zstd decompression error: %d\n", | |
119 | (int)ZSTD_getErrorCode(zstd_err)); | |
120 | goto out; | |
121 | } | |
122 | ||
123 | if (k < b) | |
124 | goto out; | |
125 | ||
126 | return (int)total_out; | |
127 | ||
128 | out: | |
129 | for (; k < b; k++) | |
130 | put_bh(bh[k]); | |
131 | ||
132 | return -EIO; | |
133 | } | |
134 | ||
135 | const struct squashfs_decompressor squashfs_zstd_comp_ops = { | |
136 | .init = zstd_init, | |
137 | .free = zstd_free, | |
138 | .decompress = zstd_uncompress, | |
139 | .id = ZSTD_COMPRESSION, | |
140 | .name = "zstd", | |
141 | .supported = 1 | |
142 | }; |