1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2013
4 * Phillip Lougher <phillip@squashfs.org.uk>
5 */
6
7 #include <linux/types.h>
8 #include <linux/slab.h>
9 #include <linux/percpu.h>
10 #include <linux/local_lock.h>
11
12 #include "squashfs_fs.h"
13 #include "squashfs_fs_sb.h"
14 #include "decompressor.h"
15 #include "squashfs.h"
16
17 /*
18 * This file implements multi-threaded decompression using percpu
19 * variables, one thread per cpu core.
20 */
21
22 struct squashfs_stream {
23 void *stream;
24 local_lock_t lock;
25 };
26
27 static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
28 void *comp_opts)
29 {
30 struct squashfs_stream *stream;
31 struct squashfs_stream __percpu *percpu;
32 int err, cpu;
33
34 percpu = alloc_percpu(struct squashfs_stream);
35 if (percpu == NULL)
36 return ERR_PTR(-ENOMEM);
37
38 for_each_possible_cpu(cpu) {
39 stream = per_cpu_ptr(percpu, cpu);
40 stream->stream = msblk->decompressor->init(msblk, comp_opts);
41 if (IS_ERR(stream->stream)) {
42 err = PTR_ERR(stream->stream);
43 goto out;
44 }
45 local_lock_init(&stream->lock);
46 }
47
48 kfree(comp_opts);
49 return (__force void *) percpu;
50
51 out:
52 for_each_possible_cpu(cpu) {
53 stream = per_cpu_ptr(percpu, cpu);
54 if (!IS_ERR_OR_NULL(stream->stream))
55 msblk->decompressor->free(stream->stream);
56 }
57 free_percpu(percpu);
58 return ERR_PTR(err);
59 }
60
61 static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
62 {
63 struct squashfs_stream __percpu *percpu =
64 (struct squashfs_stream __percpu *) msblk->stream;
65 struct squashfs_stream *stream;
66 int cpu;
67
68 if (msblk->stream) {
69 for_each_possible_cpu(cpu) {
70 stream = per_cpu_ptr(percpu, cpu);
71 msblk->decompressor->free(stream->stream);
72 }
73 free_percpu(percpu);
74 }
75 }
76
77 static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
78 int offset, int length, struct squashfs_page_actor *output)
79 {
80 struct squashfs_stream *stream;
81 struct squashfs_stream __percpu *percpu =
82 (struct squashfs_stream __percpu *) msblk->stream;
83 int res;
84
85 local_lock(&percpu->lock);
86 stream = this_cpu_ptr(percpu);
87
88 res = msblk->decompressor->decompress(msblk, stream->stream, bio,
89 offset, length, output);
90
91 local_unlock(&percpu->lock);
92
93 if (res < 0)
94 ERROR("%s decompression failed, data probably corrupt\n",
95 msblk->decompressor->name);
96
97 return res;
98 }
99
100 static int squashfs_max_decompressors(void)
101 {
102 return num_possible_cpus();
103 }
104
105 const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu = {
106 .create = squashfs_decompressor_create,
107 .destroy = squashfs_decompressor_destroy,
108 .decompress = squashfs_decompress,
109 .max_decompressors = squashfs_max_decompressors,
110 };
111
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