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
22struct squashfs_stream {
23	void			*stream;
24	local_lock_t	lock;
25};
26
27static 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
51out:
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
61static 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
77static 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
100static int squashfs_max_decompressors(void)
101{
102	return num_possible_cpus();
103}
104
105const 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