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 
22 struct squashfs_stream {
23 	void		*stream;
24 };
25 
26 void *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 
49 out:
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 
59 void 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 
75 int 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 
92 int squashfs_max_decompressors(void)
93 {
94 	return num_possible_cpus();
95 }
96