1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2019 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
6 */
7 #ifndef __EROFS_FS_COMPRESS_H
8 #define __EROFS_FS_COMPRESS_H
9
10 #include "internal.h"
11
12 enum {
13 Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
14 Z_EROFS_COMPRESSION_RUNTIME_MAX
15 };
16
17 struct z_erofs_decompress_req {
18 struct super_block *sb;
19 struct page **in, **out;
20
21 unsigned short pageofs_out;
22 unsigned int inputsize, outputsize;
23
24 /* indicate the algorithm will be used for decompression */
25 unsigned int alg;
26 bool inplace_io, partial_decoding;
27 };
28
29 /*
30 * - 0x5A110C8D ('sallocated', Z_EROFS_MAPPING_STAGING) -
31 * used to mark temporary allocated pages from other
32 * file/cached pages and NULL mapping pages.
33 */
34 #define Z_EROFS_MAPPING_STAGING ((void *)0x5A110C8D)
35
36 /* check if a page is marked as staging */
z_erofs_page_is_staging(struct page * page)37 static inline bool z_erofs_page_is_staging(struct page *page)
38 {
39 return page->mapping == Z_EROFS_MAPPING_STAGING;
40 }
41
z_erofs_put_stagingpage(struct list_head * pagepool,struct page * page)42 static inline bool z_erofs_put_stagingpage(struct list_head *pagepool,
43 struct page *page)
44 {
45 if (!z_erofs_page_is_staging(page))
46 return false;
47
48 /* staging pages should not be used by others at the same time */
49 if (page_ref_count(page) > 1)
50 put_page(page);
51 else
52 list_add(&page->lru, pagepool);
53 return true;
54 }
55
56 int z_erofs_decompress(struct z_erofs_decompress_req *rq,
57 struct list_head *pagepool);
58
59 #endif
60
61
