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
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};
25
26void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
27						void *comp_opts)
28{
29	struct squashfs_stream *stream;
30	struct squashfs_stream __percpu *percpu;
31	int err, cpu;
32
33	percpu = alloc_percpu(struct squashfs_stream);
34	if (percpu == NULL)
35		return ERR_PTR(-ENOMEM);
36
37	for_each_possible_cpu(cpu) {
38		stream = per_cpu_ptr(percpu, cpu);
39		stream->stream = msblk->decompressor->init(msblk, comp_opts);
40		if (IS_ERR(stream->stream)) {
41			err = PTR_ERR(stream->stream);
42			goto out;
43		}
44	}
45
46	kfree(comp_opts);
47	return (__force void *) percpu;
48
49out:
50	for_each_possible_cpu(cpu) {
51		stream = per_cpu_ptr(percpu, cpu);
52		if (!IS_ERR_OR_NULL(stream->stream))
53			msblk->decompressor->free(stream->stream);
54	}
55	free_percpu(percpu);
56	return ERR_PTR(err);
57}
58
59void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
60{
61	struct squashfs_stream __percpu *percpu =
62			(struct squashfs_stream __percpu *) msblk->stream;
63	struct squashfs_stream *stream;
64	int cpu;
65
66	if (msblk->stream) {
67		for_each_possible_cpu(cpu) {
68			stream = per_cpu_ptr(percpu, cpu);
69			msblk->decompressor->free(stream->stream);
70		}
71		free_percpu(percpu);
72	}
73}
74
75int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
76	int b, int offset, int length, struct squashfs_page_actor *output)
77{
78	struct squashfs_stream __percpu *percpu =
79			(struct squashfs_stream __percpu *) msblk->stream;
80	struct squashfs_stream *stream = get_cpu_ptr(percpu);
81	int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
82		offset, length, output);
83	put_cpu_ptr(stream);
84
85	if (res < 0)
86		ERROR("%s decompression failed, data probably corrupt\n",
87			msblk->decompressor->name);
88
89	return res;
90}
91
92int squashfs_max_decompressors(void)
93{
94	return num_possible_cpus();
95}