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git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/blob - drivers/md/dm-verity-fec.h
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Copyright (C) 2015 Google, Inc.
5 * Author: Sami Tolvanen <samitolvanen@google.com>
8 #ifndef DM_VERITY_FEC_H
9 #define DM_VERITY_FEC_H
11 #include "dm-verity.h"
12 #include <linux/rslib.h>
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 */
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))
26 /* maximum recursion level for verity_fec_decode */
27 #define DM_VERITY_FEC_MAX_RECURSION 4
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"
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 */
39 size_t io_size
; /* IO size for roots */
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) */
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 */
50 struct kmem_cache
*cache
; /* cache for buffers */
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 */
58 unsigned nbufs
; /* number of buffers allocated */
59 u8
*output
; /* buffer for corrected output */
61 unsigned level
; /* recursion level */
64 #ifdef CONFIG_DM_VERITY_FEC
66 /* each feature parameter requires a value */
67 #define DM_VERITY_OPTS_FEC 8
69 extern bool verity_fec_is_enabled(struct dm_verity
*v
);
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
);
75 extern unsigned verity_fec_status_table(struct dm_verity
*v
, unsigned sz
,
76 char *result
, unsigned maxlen
);
78 extern void verity_fec_finish_io(struct dm_verity_io
*io
);
79 extern void verity_fec_init_io(struct dm_verity_io
*io
);
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
,
83 struct dm_verity
*v
, unsigned *argc
,
84 const char *arg_name
);
86 extern void verity_fec_dtr(struct dm_verity
*v
);
88 extern int verity_fec_ctr_alloc(struct dm_verity
*v
);
89 extern int verity_fec_ctr(struct dm_verity
*v
);
91 #else /* !CONFIG_DM_VERITY_FEC */
93 #define DM_VERITY_OPTS_FEC 0
95 static inline bool verity_fec_is_enabled(struct dm_verity
*v
)
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
)
109 static inline unsigned verity_fec_status_table(struct dm_verity
*v
,
110 unsigned sz
, char *result
,
116 static inline void verity_fec_finish_io(struct dm_verity_io
*io
)
120 static inline void verity_fec_init_io(struct dm_verity_io
*io
)
124 static inline bool verity_is_fec_opt_arg(const char *arg_name
)
129 static inline int verity_fec_parse_opt_args(struct dm_arg_set
*as
,
132 const char *arg_name
)
137 static inline void verity_fec_dtr(struct dm_verity
*v
)
141 static inline int verity_fec_ctr_alloc(struct dm_verity
*v
)
146 static inline int verity_fec_ctr(struct dm_verity
*v
)
151 #endif /* CONFIG_DM_VERITY_FEC */
153 #endif /* DM_VERITY_FEC_H */