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