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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
a739ff3f ST |
2 | /* |
3 | * Copyright (C) 2015 Google, Inc. | |
4 | * | |
5 | * Author: Sami Tolvanen <samitolvanen@google.com> | |
a739ff3f ST |
6 | */ |
7 | ||
8 | #ifndef DM_VERITY_FEC_H | |
9 | #define DM_VERITY_FEC_H | |
10 | ||
11 | #include "dm-verity.h" | |
12 | #include <linux/rslib.h> | |
13 | ||
14 | /* Reed-Solomon(M, N) parameters */ | |
15 | #define DM_VERITY_FEC_RSM 255 | |
16 | #define DM_VERITY_FEC_MAX_RSN 253 | |
17 | #define DM_VERITY_FEC_MIN_RSN 231 /* ~10% space overhead */ | |
18 | ||
19 | /* buffers for deinterleaving and decoding */ | |
20 | #define DM_VERITY_FEC_BUF_PREALLOC 1 /* buffers to preallocate */ | |
21 | #define DM_VERITY_FEC_BUF_RS_BITS 4 /* 1 << RS blocks per buffer */ | |
22 | /* we need buffers for at most 1 << block size RS blocks */ | |
23 | #define DM_VERITY_FEC_BUF_MAX \ | |
24 | (1 << (PAGE_SHIFT - DM_VERITY_FEC_BUF_RS_BITS)) | |
25 | ||
f1a880a9 ST |
26 | /* maximum recursion level for verity_fec_decode */ |
27 | #define DM_VERITY_FEC_MAX_RECURSION 4 | |
28 | ||
a739ff3f ST |
29 | #define DM_VERITY_OPT_FEC_DEV "use_fec_from_device" |
30 | #define DM_VERITY_OPT_FEC_BLOCKS "fec_blocks" | |
31 | #define DM_VERITY_OPT_FEC_START "fec_start" | |
32 | #define DM_VERITY_OPT_FEC_ROOTS "fec_roots" | |
33 | ||
34 | /* configuration */ | |
35 | struct dm_verity_fec { | |
36 | struct dm_dev *dev; /* parity data device */ | |
37 | struct dm_bufio_client *data_bufio; /* for data dev access */ | |
38 | struct dm_bufio_client *bufio; /* for parity data access */ | |
8ca7cab8 | 39 | size_t io_size; /* IO size for roots */ |
a739ff3f ST |
40 | sector_t start; /* parity data start in blocks */ |
41 | sector_t blocks; /* number of blocks covered */ | |
42 | sector_t rounds; /* number of interleaving rounds */ | |
43 | sector_t hash_blocks; /* blocks covered after v->hash_start */ | |
44 | unsigned char roots; /* number of parity bytes, M-N of RS(M, N) */ | |
45 | unsigned char rsn; /* N of RS(M, N) */ | |
6f1c819c KO |
46 | mempool_t rs_pool; /* mempool for fio->rs */ |
47 | mempool_t prealloc_pool; /* mempool for preallocated buffers */ | |
48 | mempool_t extra_pool; /* mempool for extra buffers */ | |
49 | mempool_t output_pool; /* mempool for output */ | |
a739ff3f ST |
50 | struct kmem_cache *cache; /* cache for buffers */ |
51 | }; | |
52 | ||
53 | /* per-bio data */ | |
54 | struct dm_verity_fec_io { | |
55 | struct rs_control *rs; /* Reed-Solomon state */ | |
56 | int erasures[DM_VERITY_FEC_MAX_RSN]; /* erasures for decode_rs8 */ | |
57 | u8 *bufs[DM_VERITY_FEC_BUF_MAX]; /* bufs for deinterleaving */ | |
86a3238c | 58 | unsigned int nbufs; /* number of buffers allocated */ |
a739ff3f ST |
59 | u8 *output; /* buffer for corrected output */ |
60 | size_t output_pos; | |
86a3238c | 61 | unsigned int level; /* recursion level */ |
a739ff3f ST |
62 | }; |
63 | ||
64 | #ifdef CONFIG_DM_VERITY_FEC | |
65 | ||
66 | /* each feature parameter requires a value */ | |
67 | #define DM_VERITY_OPTS_FEC 8 | |
68 | ||
69 | extern bool verity_fec_is_enabled(struct dm_verity *v); | |
70 | ||
71 | extern int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, | |
72 | enum verity_block_type type, sector_t block, | |
73 | u8 *dest, struct bvec_iter *iter); | |
74 | ||
86a3238c HM |
75 | extern unsigned int verity_fec_status_table(struct dm_verity *v, unsigned int sz, |
76 | char *result, unsigned int maxlen); | |
a739ff3f ST |
77 | |
78 | extern void verity_fec_finish_io(struct dm_verity_io *io); | |
79 | extern void verity_fec_init_io(struct dm_verity_io *io); | |
80 | ||
81 | extern bool verity_is_fec_opt_arg(const char *arg_name); | |
82 | extern int verity_fec_parse_opt_args(struct dm_arg_set *as, | |
86a3238c | 83 | struct dm_verity *v, unsigned int *argc, |
a739ff3f ST |
84 | const char *arg_name); |
85 | ||
86 | extern void verity_fec_dtr(struct dm_verity *v); | |
87 | ||
88 | extern int verity_fec_ctr_alloc(struct dm_verity *v); | |
89 | extern int verity_fec_ctr(struct dm_verity *v); | |
90 | ||
91 | #else /* !CONFIG_DM_VERITY_FEC */ | |
92 | ||
93 | #define DM_VERITY_OPTS_FEC 0 | |
94 | ||
95 | static inline bool verity_fec_is_enabled(struct dm_verity *v) | |
96 | { | |
97 | return false; | |
98 | } | |
99 | ||
100 | static inline int verity_fec_decode(struct dm_verity *v, | |
101 | struct dm_verity_io *io, | |
102 | enum verity_block_type type, | |
103 | sector_t block, u8 *dest, | |
104 | struct bvec_iter *iter) | |
105 | { | |
106 | return -EOPNOTSUPP; | |
107 | } | |
108 | ||
86a3238c HM |
109 | static inline unsigned int verity_fec_status_table(struct dm_verity *v, |
110 | unsigned int sz, char *result, | |
111 | unsigned int maxlen) | |
a739ff3f ST |
112 | { |
113 | return sz; | |
114 | } | |
115 | ||
116 | static inline void verity_fec_finish_io(struct dm_verity_io *io) | |
117 | { | |
118 | } | |
119 | ||
120 | static inline void verity_fec_init_io(struct dm_verity_io *io) | |
121 | { | |
122 | } | |
123 | ||
124 | static inline bool verity_is_fec_opt_arg(const char *arg_name) | |
125 | { | |
126 | return false; | |
127 | } | |
128 | ||
129 | static inline int verity_fec_parse_opt_args(struct dm_arg_set *as, | |
130 | struct dm_verity *v, | |
86a3238c | 131 | unsigned int *argc, |
a739ff3f ST |
132 | const char *arg_name) |
133 | { | |
134 | return -EINVAL; | |
135 | } | |
136 | ||
137 | static inline void verity_fec_dtr(struct dm_verity *v) | |
138 | { | |
139 | } | |
140 | ||
141 | static inline int verity_fec_ctr_alloc(struct dm_verity *v) | |
142 | { | |
143 | return 0; | |
144 | } | |
145 | ||
146 | static inline int verity_fec_ctr(struct dm_verity *v) | |
147 | { | |
148 | return 0; | |
149 | } | |
150 | ||
151 | #endif /* CONFIG_DM_VERITY_FEC */ | |
152 | ||
153 | #endif /* DM_VERITY_FEC_H */ |