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 int inpages, outpages;
15 unsigned short pageofs_in, pageofs_out;
16 unsigned int inputsize, outputsize;
17
18 unsigned int alg; /* the algorithm for decompression */
19 bool inplace_io, partial_decoding, fillgaps;
20 gfp_t gfp; /* allocation flags for extra temporary buffers */
21 };
22
23 struct z_erofs_decompressor {
24 int (*config)(struct super_block *sb, struct erofs_super_block *dsb,
25 void *data, int size);
26 int (*decompress)(struct z_erofs_decompress_req *rq,
27 struct page **pagepool);
28 int (*init)(void);
29 void (*exit)(void);
30 char *name;
31 };
32
33 #define Z_EROFS_SHORTLIVED_PAGE (-1UL << 2)
34 #define Z_EROFS_PREALLOCATED_FOLIO ((void *)(-2UL << 2))
35
36 /*
37 * Currently, short-lived pages are pages directly from buddy system
38 * with specific page->private (Z_EROFS_SHORTLIVED_PAGE).
39 * In the future world of Memdescs, it should be type 0 (Misc) memory
40 * which type can be checked with a new helper.
41 */
z_erofs_is_shortlived_page(struct page * page)42 static inline bool z_erofs_is_shortlived_page(struct page *page)
43 {
44 return page->private == Z_EROFS_SHORTLIVED_PAGE;
45 }
46
z_erofs_put_shortlivedpage(struct page ** pagepool,struct page * page)47 static inline bool z_erofs_put_shortlivedpage(struct page **pagepool,
48 struct page *page)
49 {
50 if (!z_erofs_is_shortlived_page(page))
51 return false;
52 erofs_pagepool_add(pagepool, page);
53 return true;
54 }
55
56 extern const struct z_erofs_decompressor z_erofs_lzma_decomp;
57 extern const struct z_erofs_decompressor z_erofs_deflate_decomp;
58 extern const struct z_erofs_decompressor z_erofs_zstd_decomp;
59 extern const struct z_erofs_decompressor *z_erofs_decomp[];
60
61 struct z_erofs_stream_dctx {
62 struct z_erofs_decompress_req *rq;
63 int no, ni; /* the current {en,de}coded page # */
64
65 unsigned int avail_out; /* remaining bytes in the decoded buffer */
66 unsigned int inbuf_pos, inbuf_sz;
67 /* current status of the encoded buffer */
68 u8 *kin, *kout; /* buffer mapped pointers */
69 void *bounce; /* bounce buffer for inplace I/Os */
70 bool bounced; /* is the bounce buffer used now? */
71 };
72
73 int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
74 void **src, struct page **pgpl);
75 int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
76 unsigned int padbufsize);
77 int __init z_erofs_init_decompressor(void);
78 void z_erofs_exit_decompressor(void);
79 #endif
80