1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2013
* Minchan Kim <minchan@kernel.org>
*/
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/cpumask.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "decompressor.h"
#include "squashfs.h"
/*
* This file implements multi-threaded decompression in the
* decompressor framework
*/
/*
* The reason that multiply two is that a CPU can request new I/O
* while it is waiting previous request.
*/
#define MAX_DECOMPRESSOR (num_online_cpus() * 2)
static int squashfs_max_decompressors(void)
{
return MAX_DECOMPRESSOR;
}
struct squashfs_stream {
void *comp_opts;
struct list_head strm_list;
struct mutex mutex;
int avail_decomp;
wait_queue_head_t wait;
};
struct decomp_stream {
void *stream;
struct list_head list;
};
static void put_decomp_stream(struct decomp_stream *decomp_strm,
struct squashfs_stream *stream)
{
mutex_lock(&stream->mutex);
list_add(&decomp_strm->list, &stream->strm_list);
mutex_unlock(&stream->mutex);
wake_up(&stream->wait);
}
static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
void *comp_opts)
{
struct squashfs_stream *stream;
struct decomp_stream *decomp_strm = NULL;
int err = -ENOMEM;
stream = kzalloc(sizeof(*stream), GFP_KERNEL);
if (!stream)
goto out;
stream->comp_opts = comp_opts;
mutex_init(&stream->mutex);
INIT_LIST_HEAD(&stream->strm_list);
init_waitqueue_head(&stream->wait);
/*
* We should have a decompressor at least as default
* so if we fail to allocate new decompressor dynamically,
* we could always fall back to default decompressor and
* file system works.
*/
decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL);
if (!decomp_strm)
goto out;
decomp_strm->stream = msblk->decompressor->init(msblk,
stream->comp_opts);
if (IS_ERR(decomp_strm->stream)) {
err = PTR_ERR(decomp_strm->stream);
goto out;
}
list_add(&decomp_strm->list, &stream->strm_list);
stream->avail_decomp = 1;
return stream;
out:
kfree(decomp_strm);
kfree(stream);
return ERR_PTR(err);
}
static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
{
struct squashfs_stream *stream = msblk->stream;
if (stream) {
struct decomp_stream *decomp_strm;
while (!list_empty(&stream->strm_list)) {
decomp_strm = list_entry(stream->strm_list.prev,
struct decomp_stream, list);
list_del(&decomp_strm->list);
msblk->decompressor->free(decomp_strm->stream);
kfree(decomp_strm);
stream->avail_decomp--;
}
WARN_ON(stream->avail_decomp);
kfree(stream->comp_opts);
kfree(stream);
}
}
static struct decomp_stream *get_decomp_stream(struct squashfs_sb_info *msblk,
struct squashfs_stream *stream)
{
struct decomp_stream *decomp_strm;
while (1) {
mutex_lock(&stream->mutex);
/* There is available decomp_stream */
if (!list_empty(&stream->strm_list)) {
decomp_strm = list_entry(stream->strm_list.prev,
struct decomp_stream, list);
list_del(&decomp_strm->list);
mutex_unlock(&stream->mutex);
break;
}
/*
* If there is no available decomp and already full,
* let's wait for releasing decomp from other users.
*/
if (stream->avail_decomp >= MAX_DECOMPRESSOR)
goto wait;
/* Let's allocate new decomp */
decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL);
if (!decomp_strm)
goto wait;
decomp_strm->stream = msblk->decompressor->init(msblk,
stream->comp_opts);
if (IS_ERR(decomp_strm->stream)) {
kfree(decomp_strm);
goto wait;
}
stream->avail_decomp++;
WARN_ON(stream->avail_decomp > MAX_DECOMPRESSOR);
mutex_unlock(&stream->mutex);
break;
wait:
/*
* If system memory is tough, let's for other's
* releasing instead of hurting VM because it could
* make page cache thrashing.
*/
mutex_unlock(&stream->mutex);
wait_event(stream->wait,
!list_empty(&stream->strm_list));
}
return decomp_strm;
}
static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
int offset, int length,
struct squashfs_page_actor *output)
{
int res;
struct squashfs_stream *stream = msblk->stream;
struct decomp_stream *decomp_stream = get_decomp_stream(msblk, stream);
res = msblk->decompressor->decompress(msblk, decomp_stream->stream,
bio, offset, length, output);
put_decomp_stream(decomp_stream, stream);
if (res < 0)
ERROR("%s decompression failed, data probably corrupt\n",
msblk->decompressor->name);
return res;
}
const struct squashfs_decompressor_thread_ops squashfs_decompressor_multi = {
.create = squashfs_decompressor_create,
.destroy = squashfs_decompressor_destroy,
.decompress = squashfs_decompress,
.max_decompressors = squashfs_max_decompressors,
};
|
