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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * Copyright (C) 2015 Google, Inc.4 *5 * Author: Sami Tolvanen <samitolvanen@google.com>6 */7 8#ifndef DM_VERITY_FEC_H9#define DM_VERITY_FEC_H10 11#include "dm-verity.h"12#include <linux/rslib.h>13 14/* Reed-Solomon(M, N) parameters */15#define DM_VERITY_FEC_RSM 25516#define DM_VERITY_FEC_MAX_RSN 25317#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 26/* maximum recursion level for verity_fec_decode */27#define DM_VERITY_FEC_MAX_RECURSION 428 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 */35struct 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 */51};52 53/* per-bio data */54struct 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 int nbufs; /* number of buffers allocated */59 u8 *output; /* buffer for corrected output */60 unsigned int level; /* recursion level */61};62 63#ifdef CONFIG_DM_VERITY_FEC64 65/* each feature parameter requires a value */66#define DM_VERITY_OPTS_FEC 867 68extern bool verity_fec_is_enabled(struct dm_verity *v);69 70extern int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,71 enum verity_block_type type, sector_t block,72 u8 *dest);73 74extern unsigned int verity_fec_status_table(struct dm_verity *v, unsigned int sz,75 char *result, unsigned int maxlen);76 77extern void verity_fec_finish_io(struct dm_verity_io *io);78extern void verity_fec_init_io(struct dm_verity_io *io);79 80extern bool verity_is_fec_opt_arg(const char *arg_name);81extern int verity_fec_parse_opt_args(struct dm_arg_set *as,82 struct dm_verity *v, unsigned int *argc,83 const char *arg_name);84 85extern void verity_fec_dtr(struct dm_verity *v);86 87extern int verity_fec_ctr_alloc(struct dm_verity *v);88extern int verity_fec_ctr(struct dm_verity *v);89 90#else /* !CONFIG_DM_VERITY_FEC */91 92#define DM_VERITY_OPTS_FEC 093 94static inline bool verity_fec_is_enabled(struct dm_verity *v)95{96 return false;97}98 99static inline int verity_fec_decode(struct dm_verity *v,100 struct dm_verity_io *io,101 enum verity_block_type type,102 sector_t block, u8 *dest)103{104 return -EOPNOTSUPP;105}106 107static inline unsigned int verity_fec_status_table(struct dm_verity *v,108 unsigned int sz, char *result,109 unsigned int maxlen)110{111 return sz;112}113 114static inline void verity_fec_finish_io(struct dm_verity_io *io)115{116}117 118static inline void verity_fec_init_io(struct dm_verity_io *io)119{120}121 122static inline bool verity_is_fec_opt_arg(const char *arg_name)123{124 return false;125}126 127static inline int verity_fec_parse_opt_args(struct dm_arg_set *as,128 struct dm_verity *v,129 unsigned int *argc,130 const char *arg_name)131{132 return -EINVAL;133}134 135static inline void verity_fec_dtr(struct dm_verity *v)136{137}138 139static inline int verity_fec_ctr_alloc(struct dm_verity *v)140{141 return 0;142}143 144static inline int verity_fec_ctr(struct dm_verity *v)145{146 return 0;147}148 149#endif /* CONFIG_DM_VERITY_FEC */150 151#endif /* DM_VERITY_FEC_H */152