1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * Copyright (C) 2019 HUAWEI, Inc. |
4 | * https://www.huawei.com/ |
5 | */ |
6 | #ifndef __EROFS_FS_COMPRESS_H |
7 | #define __EROFS_FS_COMPRESS_H |
8 | |
9 | #include "internal.h" |
10 | |
11 | struct z_erofs_decompress_req { |
12 | struct super_block *sb; |
13 | struct page **in, **out; |
14 | unsigned short pageofs_in, pageofs_out; |
15 | unsigned int inputsize, outputsize; |
16 | |
17 | unsigned int alg; /* the algorithm for decompression */ |
18 | bool inplace_io, partial_decoding, fillgaps; |
19 | gfp_t gfp; /* allocation flags for extra temporary buffers */ |
20 | }; |
21 | |
22 | struct z_erofs_decompressor { |
23 | int (*config)(struct super_block *sb, struct erofs_super_block *dsb, |
24 | void *data, int size); |
25 | int (*decompress)(struct z_erofs_decompress_req *rq, |
26 | struct page **pagepool); |
27 | char *name; |
28 | }; |
29 | |
30 | /* some special page->private (unsigned long, see below) */ |
31 | #define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2) |
32 | #define Z_EROFS_PREALLOCATED_PAGE (-2UL << 2) |
33 | |
34 | /* |
35 | * For all pages in a pcluster, page->private should be one of |
36 | * Type Last 2bits page->private |
37 | * short-lived page 00 Z_EROFS_SHORTLIVED_PAGE |
38 | * preallocated page (tryalloc) 00 Z_EROFS_PREALLOCATED_PAGE |
39 | * cached/managed page 00 pointer to z_erofs_pcluster |
40 | * online page (file-backed, 01/10/11 sub-index << 2 | count |
41 | * some pages can be used for inplace I/O) |
42 | * |
43 | * page->mapping should be one of |
44 | * Type page->mapping |
45 | * short-lived page NULL |
46 | * preallocated page NULL |
47 | * cached/managed page non-NULL or NULL (invalidated/truncated page) |
48 | * online page non-NULL |
49 | * |
50 | * For all managed pages, PG_private should be set with 1 extra refcount, |
51 | * which is used for page reclaim / migration. |
52 | */ |
53 | |
54 | /* |
55 | * short-lived pages are pages directly from buddy system with specific |
56 | * page->private (no need to set PagePrivate since these are non-LRU / |
57 | * non-movable pages and bypass reclaim / migration code). |
58 | */ |
59 | static inline bool z_erofs_is_shortlived_page(struct page *page) |
60 | { |
61 | if (page->private != Z_EROFS_SHORTLIVED_PAGE) |
62 | return false; |
63 | |
64 | DBG_BUGON(page->mapping); |
65 | return true; |
66 | } |
67 | |
68 | static inline bool z_erofs_put_shortlivedpage(struct page **pagepool, |
69 | struct page *page) |
70 | { |
71 | if (!z_erofs_is_shortlived_page(page)) |
72 | return false; |
73 | |
74 | /* short-lived pages should not be used by others at the same time */ |
75 | if (page_ref_count(page) > 1) { |
76 | put_page(page); |
77 | } else { |
78 | /* follow the pcluster rule above. */ |
79 | erofs_pagepool_add(pagepool, page); |
80 | } |
81 | return true; |
82 | } |
83 | |
84 | int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf, |
85 | unsigned int padbufsize); |
86 | extern const struct z_erofs_decompressor erofs_decompressors[]; |
87 | |
88 | /* prototypes for specific algorithms */ |
89 | int z_erofs_load_lzma_config(struct super_block *sb, |
90 | struct erofs_super_block *dsb, void *data, int size); |
91 | int z_erofs_load_deflate_config(struct super_block *sb, |
92 | struct erofs_super_block *dsb, void *data, int size); |
93 | int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, |
94 | struct page **pagepool); |
95 | int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, |
96 | struct page **pagepool); |
97 | #endif |
98 | |