Commit | Line | Data |
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cd59c2ec MK |
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 | ||
34 | int squashfs_max_decompressors(void) | |
35 | { | |
36 | return MAX_DECOMPRESSOR; | |
37 | } | |
38 | ||
39 | ||
40 | struct 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 | ||
49 | struct decomp_stream { | |
50 | void *stream; | |
51 | struct list_head list; | |
52 | }; | |
53 | ||
54 | ||
55 | static 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 | ||
64 | void *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 | ||
101 | out: | |
102 | kfree(decomp_strm); | |
103 | kfree(stream); | |
104 | return ERR_PTR(err); | |
105 | } | |
106 | ||
107 | ||
108 | void 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 | } | |
ed4f381e PL |
122 | WARN_ON(stream->avail_decomp); |
123 | kfree(stream->comp_opts); | |
124 | kfree(stream); | |
cd59c2ec | 125 | } |
cd59c2ec MK |
126 | } |
127 | ||
128 | ||
129 | static 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; | |
170 | wait: | |
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 | ||
846b730e PL |
185 | int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh, |
186 | int b, int offset, int length, struct squashfs_page_actor *output) | |
cd59c2ec MK |
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, | |
846b730e | 192 | bh, b, offset, length, output); |
cd59c2ec MK |
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 | } |