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20c8ccb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
cd59c2ec MK |
2 | /* |
3 | * Copyright (c) 2013 | |
4 | * Minchan Kim <minchan@kernel.org> | |
cd59c2ec MK |
5 | */ |
6 | #include <linux/types.h> | |
7 | #include <linux/mutex.h> | |
8 | #include <linux/slab.h> | |
93e72b3c | 9 | #include <linux/bio.h> |
cd59c2ec MK |
10 | #include <linux/sched.h> |
11 | #include <linux/wait.h> | |
12 | #include <linux/cpumask.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 in the | |
21 | * decompressor framework | |
22 | */ | |
23 | ||
24 | ||
25 | /* | |
26 | * The reason that multiply two is that a CPU can request new I/O | |
27 | * while it is waiting previous request. | |
28 | */ | |
29 | #define MAX_DECOMPRESSOR (num_online_cpus() * 2) | |
30 | ||
31 | ||
80f78409 | 32 | static int squashfs_max_decompressors(void) |
cd59c2ec MK |
33 | { |
34 | return MAX_DECOMPRESSOR; | |
35 | } | |
36 | ||
cd59c2ec MK |
37 | struct squashfs_stream { |
38 | void *comp_opts; | |
39 | struct list_head strm_list; | |
40 | struct mutex mutex; | |
41 | int avail_decomp; | |
42 | wait_queue_head_t wait; | |
43 | }; | |
44 | ||
45 | ||
46 | struct decomp_stream { | |
47 | void *stream; | |
48 | struct list_head list; | |
49 | }; | |
50 | ||
51 | ||
52 | static void put_decomp_stream(struct decomp_stream *decomp_strm, | |
53 | struct squashfs_stream *stream) | |
54 | { | |
55 | mutex_lock(&stream->mutex); | |
56 | list_add(&decomp_strm->list, &stream->strm_list); | |
57 | mutex_unlock(&stream->mutex); | |
58 | wake_up(&stream->wait); | |
59 | } | |
60 | ||
80f78409 | 61 | static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk, |
cd59c2ec MK |
62 | void *comp_opts) |
63 | { | |
64 | struct squashfs_stream *stream; | |
65 | struct decomp_stream *decomp_strm = NULL; | |
66 | int err = -ENOMEM; | |
67 | ||
68 | stream = kzalloc(sizeof(*stream), GFP_KERNEL); | |
69 | if (!stream) | |
70 | goto out; | |
71 | ||
72 | stream->comp_opts = comp_opts; | |
73 | mutex_init(&stream->mutex); | |
74 | INIT_LIST_HEAD(&stream->strm_list); | |
75 | init_waitqueue_head(&stream->wait); | |
76 | ||
77 | /* | |
78 | * We should have a decompressor at least as default | |
79 | * so if we fail to allocate new decompressor dynamically, | |
80 | * we could always fall back to default decompressor and | |
81 | * file system works. | |
82 | */ | |
83 | decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL); | |
84 | if (!decomp_strm) | |
85 | goto out; | |
86 | ||
87 | decomp_strm->stream = msblk->decompressor->init(msblk, | |
88 | stream->comp_opts); | |
89 | if (IS_ERR(decomp_strm->stream)) { | |
90 | err = PTR_ERR(decomp_strm->stream); | |
91 | goto out; | |
92 | } | |
93 | ||
94 | list_add(&decomp_strm->list, &stream->strm_list); | |
95 | stream->avail_decomp = 1; | |
96 | return stream; | |
97 | ||
98 | out: | |
99 | kfree(decomp_strm); | |
100 | kfree(stream); | |
101 | return ERR_PTR(err); | |
102 | } | |
103 | ||
104 | ||
80f78409 | 105 | static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk) |
cd59c2ec MK |
106 | { |
107 | struct squashfs_stream *stream = msblk->stream; | |
108 | if (stream) { | |
109 | struct decomp_stream *decomp_strm; | |
110 | ||
111 | while (!list_empty(&stream->strm_list)) { | |
112 | decomp_strm = list_entry(stream->strm_list.prev, | |
113 | struct decomp_stream, list); | |
114 | list_del(&decomp_strm->list); | |
115 | msblk->decompressor->free(decomp_strm->stream); | |
116 | kfree(decomp_strm); | |
117 | stream->avail_decomp--; | |
118 | } | |
ed4f381e PL |
119 | WARN_ON(stream->avail_decomp); |
120 | kfree(stream->comp_opts); | |
121 | kfree(stream); | |
cd59c2ec | 122 | } |
cd59c2ec MK |
123 | } |
124 | ||
125 | ||
126 | static struct decomp_stream *get_decomp_stream(struct squashfs_sb_info *msblk, | |
127 | struct squashfs_stream *stream) | |
128 | { | |
129 | struct decomp_stream *decomp_strm; | |
130 | ||
131 | while (1) { | |
132 | mutex_lock(&stream->mutex); | |
133 | ||
134 | /* There is available decomp_stream */ | |
135 | if (!list_empty(&stream->strm_list)) { | |
136 | decomp_strm = list_entry(stream->strm_list.prev, | |
137 | struct decomp_stream, list); | |
138 | list_del(&decomp_strm->list); | |
139 | mutex_unlock(&stream->mutex); | |
140 | break; | |
141 | } | |
142 | ||
143 | /* | |
144 | * If there is no available decomp and already full, | |
145 | * let's wait for releasing decomp from other users. | |
146 | */ | |
fb40fe04 | 147 | if (stream->avail_decomp >= msblk->max_thread_num) |
cd59c2ec MK |
148 | goto wait; |
149 | ||
150 | /* Let's allocate new decomp */ | |
151 | decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL); | |
152 | if (!decomp_strm) | |
153 | goto wait; | |
154 | ||
155 | decomp_strm->stream = msblk->decompressor->init(msblk, | |
156 | stream->comp_opts); | |
157 | if (IS_ERR(decomp_strm->stream)) { | |
158 | kfree(decomp_strm); | |
159 | goto wait; | |
160 | } | |
161 | ||
162 | stream->avail_decomp++; | |
fb40fe04 | 163 | WARN_ON(stream->avail_decomp > msblk->max_thread_num); |
cd59c2ec MK |
164 | |
165 | mutex_unlock(&stream->mutex); | |
166 | break; | |
167 | wait: | |
168 | /* | |
169 | * If system memory is tough, let's for other's | |
170 | * releasing instead of hurting VM because it could | |
171 | * make page cache thrashing. | |
172 | */ | |
173 | mutex_unlock(&stream->mutex); | |
174 | wait_event(stream->wait, | |
175 | !list_empty(&stream->strm_list)); | |
176 | } | |
177 | ||
178 | return decomp_strm; | |
179 | } | |
180 | ||
181 | ||
80f78409 | 182 | static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio, |
93e72b3c PL |
183 | int offset, int length, |
184 | struct squashfs_page_actor *output) | |
cd59c2ec MK |
185 | { |
186 | int res; | |
187 | struct squashfs_stream *stream = msblk->stream; | |
188 | struct decomp_stream *decomp_stream = get_decomp_stream(msblk, stream); | |
189 | res = msblk->decompressor->decompress(msblk, decomp_stream->stream, | |
93e72b3c | 190 | bio, offset, length, output); |
cd59c2ec MK |
191 | put_decomp_stream(decomp_stream, stream); |
192 | if (res < 0) | |
193 | ERROR("%s decompression failed, data probably corrupt\n", | |
194 | msblk->decompressor->name); | |
195 | return res; | |
196 | } | |
80f78409 XN |
197 | |
198 | const struct squashfs_decompressor_thread_ops squashfs_decompressor_multi = { | |
199 | .create = squashfs_decompressor_create, | |
200 | .destroy = squashfs_decompressor_destroy, | |
201 | .decompress = squashfs_decompress, | |
202 | .max_decompressors = squashfs_max_decompressors, | |
203 | }; |