source: src/linux/universal/linux-4.9/fs/squashfs/decompressor_multi_percpu.c @ 31630

Last change on this file since 31630 was 31630, checked in by brainslayer, 6 weeks ago

new fs is compatible with standard squashfs, just smaller

File size: 2.3 KB
Line 
1/*
2 * Copyright (c) 2013
3 * Phillip Lougher <phillip@squashfs.org.uk>
4 *
5 * This work is licensed under the terms of the GNU GPL, version 2. See
6 * the COPYING file in the top-level directory.
7 */
8
9#include <linux/types.h>
10#include <linux/slab.h>
11#include <linux/percpu.h>
12#include <linux/buffer_head.h>
13
14#include "squashfs_fs.h"
15#include "squashfs_fs_sb.h"
16#include "decompressor.h"
17#include "squashfs.h"
18
19/*
20 * This file implements multi-threaded decompression using percpu
21 * variables, one thread per cpu core.
22 */
23
24struct squashfs_stream {
25        void            *stream;
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        }
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
61void 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
77int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
78        int b, int offset, int length, struct squashfs_page_actor *output)
79{
80        struct squashfs_stream __percpu *percpu =
81                        (struct squashfs_stream __percpu *) msblk->stream;
82        struct squashfs_stream *stream = get_cpu_ptr(percpu);
83        int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
84                offset, length, output);
85        put_cpu_ptr(stream);
86
87        if (res < 0)
88                ERROR("%s decompression failed, data probably corrupt\n",
89                        msblk->decompressor->name);
90
91        return res;
92}
93
94int squashfs_max_decompressors(void)
95{
96        return num_possible_cpus();
97}
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