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-rw-r--r--fs/squashfs/decompressor_multi.c198
1 files changed, 198 insertions, 0 deletions
diff --git a/fs/squashfs/decompressor_multi.c b/fs/squashfs/decompressor_multi.c
new file mode 100644
index 000000000000..d6008a636479
--- /dev/null
+++ b/fs/squashfs/decompressor_multi.c
@@ -0,0 +1,198 @@
1/*
2 * Copyright (c) 2013
3 * Minchan Kim <minchan@kernel.org>
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#include <linux/types.h>
9#include <linux/mutex.h>
10#include <linux/slab.h>
11#include <linux/buffer_head.h>
12#include <linux/sched.h>
13#include <linux/wait.h>
14#include <linux/cpumask.h>
15
16#include "squashfs_fs.h"
17#include "squashfs_fs_sb.h"
18#include "decompressor.h"
19#include "squashfs.h"
20
21/*
22 * This file implements multi-threaded decompression in the
23 * decompressor framework
24 */
25
26
27/*
28 * The reason that multiply two is that a CPU can request new I/O
29 * while it is waiting previous request.
30 */
31#define MAX_DECOMPRESSOR (num_online_cpus() * 2)
32
33
34int squashfs_max_decompressors(void)
35{
36 return MAX_DECOMPRESSOR;
37}
38
39
40struct squashfs_stream {
41 void *comp_opts;
42 struct list_head strm_list;
43 struct mutex mutex;
44 int avail_decomp;
45 wait_queue_head_t wait;
46};
47
48
49struct decomp_stream {
50 void *stream;
51 struct list_head list;
52};
53
54
55static void put_decomp_stream(struct decomp_stream *decomp_strm,
56 struct squashfs_stream *stream)
57{
58 mutex_lock(&stream->mutex);
59 list_add(&decomp_strm->list, &stream->strm_list);
60 mutex_unlock(&stream->mutex);
61 wake_up(&stream->wait);
62}
63
64void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
65 void *comp_opts)
66{
67 struct squashfs_stream *stream;
68 struct decomp_stream *decomp_strm = NULL;
69 int err = -ENOMEM;
70
71 stream = kzalloc(sizeof(*stream), GFP_KERNEL);
72 if (!stream)
73 goto out;
74
75 stream->comp_opts = comp_opts;
76 mutex_init(&stream->mutex);
77 INIT_LIST_HEAD(&stream->strm_list);
78 init_waitqueue_head(&stream->wait);
79
80 /*
81 * We should have a decompressor at least as default
82 * so if we fail to allocate new decompressor dynamically,
83 * we could always fall back to default decompressor and
84 * file system works.
85 */
86 decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL);
87 if (!decomp_strm)
88 goto out;
89
90 decomp_strm->stream = msblk->decompressor->init(msblk,
91 stream->comp_opts);
92 if (IS_ERR(decomp_strm->stream)) {
93 err = PTR_ERR(decomp_strm->stream);
94 goto out;
95 }
96
97 list_add(&decomp_strm->list, &stream->strm_list);
98 stream->avail_decomp = 1;
99 return stream;
100
101out:
102 kfree(decomp_strm);
103 kfree(stream);
104 return ERR_PTR(err);
105}
106
107
108void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
109{
110 struct squashfs_stream *stream = msblk->stream;
111 if (stream) {
112 struct decomp_stream *decomp_strm;
113
114 while (!list_empty(&stream->strm_list)) {
115 decomp_strm = list_entry(stream->strm_list.prev,
116 struct decomp_stream, list);
117 list_del(&decomp_strm->list);
118 msblk->decompressor->free(decomp_strm->stream);
119 kfree(decomp_strm);
120 stream->avail_decomp--;
121 }
122 WARN_ON(stream->avail_decomp);
123 kfree(stream->comp_opts);
124 kfree(stream);
125 }
126}
127
128
129static struct decomp_stream *get_decomp_stream(struct squashfs_sb_info *msblk,
130 struct squashfs_stream *stream)
131{
132 struct decomp_stream *decomp_strm;
133
134 while (1) {
135 mutex_lock(&stream->mutex);
136
137 /* There is available decomp_stream */
138 if (!list_empty(&stream->strm_list)) {
139 decomp_strm = list_entry(stream->strm_list.prev,
140 struct decomp_stream, list);
141 list_del(&decomp_strm->list);
142 mutex_unlock(&stream->mutex);
143 break;
144 }
145
146 /*
147 * If there is no available decomp and already full,
148 * let's wait for releasing decomp from other users.
149 */
150 if (stream->avail_decomp >= MAX_DECOMPRESSOR)
151 goto wait;
152
153 /* Let's allocate new decomp */
154 decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL);
155 if (!decomp_strm)
156 goto wait;
157
158 decomp_strm->stream = msblk->decompressor->init(msblk,
159 stream->comp_opts);
160 if (IS_ERR(decomp_strm->stream)) {
161 kfree(decomp_strm);
162 goto wait;
163 }
164
165 stream->avail_decomp++;
166 WARN_ON(stream->avail_decomp > MAX_DECOMPRESSOR);
167
168 mutex_unlock(&stream->mutex);
169 break;
170wait:
171 /*
172 * If system memory is tough, let's for other's
173 * releasing instead of hurting VM because it could
174 * make page cache thrashing.
175 */
176 mutex_unlock(&stream->mutex);
177 wait_event(stream->wait,
178 !list_empty(&stream->strm_list));
179 }
180
181 return decomp_strm;
182}
183
184
185int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh,
186 int b, int offset, int length, struct squashfs_page_actor *output)
187{
188 int res;
189 struct squashfs_stream *stream = msblk->stream;
190 struct decomp_stream *decomp_stream = get_decomp_stream(msblk, stream);
191 res = msblk->decompressor->decompress(msblk, decomp_stream->stream,
192 bh, b, offset, length, output);
193 put_decomp_stream(decomp_stream, stream);
194 if (res < 0)
195 ERROR("%s decompression failed, data probably corrupt\n",
196 msblk->decompressor->name);
197 return res;
198}
generated by cgit v1.2.2 (git 2.25.0) at 2026-04-07 22:39:27 -0400