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153 lines
4.2 KiB
153 lines
4.2 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/* |
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* Copyright (C) 2015 Google, Inc. |
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* |
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* Author: Sami Tolvanen <[email protected]> |
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*/ |
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#ifndef DM_VERITY_FEC_H |
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#define DM_VERITY_FEC_H |
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#include "dm-verity.h" |
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#include <linux/rslib.h> |
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/* Reed-Solomon(M, N) parameters */ |
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#define DM_VERITY_FEC_RSM 255 |
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#define DM_VERITY_FEC_MAX_RSN 253 |
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#define DM_VERITY_FEC_MIN_RSN 231 /* ~10% space overhead */ |
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/* buffers for deinterleaving and decoding */ |
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#define DM_VERITY_FEC_BUF_PREALLOC 1 /* buffers to preallocate */ |
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#define DM_VERITY_FEC_BUF_RS_BITS 4 /* 1 << RS blocks per buffer */ |
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/* we need buffers for at most 1 << block size RS blocks */ |
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#define DM_VERITY_FEC_BUF_MAX \ |
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(1 << (PAGE_SHIFT - DM_VERITY_FEC_BUF_RS_BITS)) |
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/* maximum recursion level for verity_fec_decode */ |
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#define DM_VERITY_FEC_MAX_RECURSION 4 |
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#define DM_VERITY_OPT_FEC_DEV "use_fec_from_device" |
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#define DM_VERITY_OPT_FEC_BLOCKS "fec_blocks" |
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#define DM_VERITY_OPT_FEC_START "fec_start" |
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#define DM_VERITY_OPT_FEC_ROOTS "fec_roots" |
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/* configuration */ |
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struct dm_verity_fec { |
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struct dm_dev *dev; /* parity data device */ |
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struct dm_bufio_client *data_bufio; /* for data dev access */ |
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struct dm_bufio_client *bufio; /* for parity data access */ |
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size_t io_size; /* IO size for roots */ |
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sector_t start; /* parity data start in blocks */ |
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sector_t blocks; /* number of blocks covered */ |
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sector_t rounds; /* number of interleaving rounds */ |
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sector_t hash_blocks; /* blocks covered after v->hash_start */ |
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unsigned char roots; /* number of parity bytes, M-N of RS(M, N) */ |
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unsigned char rsn; /* N of RS(M, N) */ |
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mempool_t rs_pool; /* mempool for fio->rs */ |
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mempool_t prealloc_pool; /* mempool for preallocated buffers */ |
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mempool_t extra_pool; /* mempool for extra buffers */ |
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mempool_t output_pool; /* mempool for output */ |
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struct kmem_cache *cache; /* cache for buffers */ |
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}; |
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/* per-bio data */ |
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struct dm_verity_fec_io { |
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struct rs_control *rs; /* Reed-Solomon state */ |
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int erasures[DM_VERITY_FEC_MAX_RSN]; /* erasures for decode_rs8 */ |
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u8 *bufs[DM_VERITY_FEC_BUF_MAX]; /* bufs for deinterleaving */ |
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unsigned nbufs; /* number of buffers allocated */ |
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u8 *output; /* buffer for corrected output */ |
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size_t output_pos; |
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unsigned level; /* recursion level */ |
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}; |
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#ifdef CONFIG_DM_VERITY_FEC |
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/* each feature parameter requires a value */ |
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#define DM_VERITY_OPTS_FEC 8 |
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extern bool verity_fec_is_enabled(struct dm_verity *v); |
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extern int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io, |
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enum verity_block_type type, sector_t block, |
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u8 *dest, struct bvec_iter *iter); |
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extern unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz, |
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char *result, unsigned maxlen); |
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extern void verity_fec_finish_io(struct dm_verity_io *io); |
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extern void verity_fec_init_io(struct dm_verity_io *io); |
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extern bool verity_is_fec_opt_arg(const char *arg_name); |
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extern int verity_fec_parse_opt_args(struct dm_arg_set *as, |
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struct dm_verity *v, unsigned *argc, |
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const char *arg_name); |
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extern void verity_fec_dtr(struct dm_verity *v); |
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extern int verity_fec_ctr_alloc(struct dm_verity *v); |
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extern int verity_fec_ctr(struct dm_verity *v); |
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#else /* !CONFIG_DM_VERITY_FEC */ |
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#define DM_VERITY_OPTS_FEC 0 |
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static inline bool verity_fec_is_enabled(struct dm_verity *v) |
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{ |
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return false; |
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} |
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static inline int verity_fec_decode(struct dm_verity *v, |
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struct dm_verity_io *io, |
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enum verity_block_type type, |
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sector_t block, u8 *dest, |
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struct bvec_iter *iter) |
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{ |
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return -EOPNOTSUPP; |
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} |
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static inline unsigned verity_fec_status_table(struct dm_verity *v, |
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unsigned sz, char *result, |
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unsigned maxlen) |
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{ |
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return sz; |
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} |
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static inline void verity_fec_finish_io(struct dm_verity_io *io) |
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{ |
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} |
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static inline void verity_fec_init_io(struct dm_verity_io *io) |
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{ |
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} |
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static inline bool verity_is_fec_opt_arg(const char *arg_name) |
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{ |
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return false; |
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} |
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static inline int verity_fec_parse_opt_args(struct dm_arg_set *as, |
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struct dm_verity *v, |
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unsigned *argc, |
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const char *arg_name) |
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{ |
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return -EINVAL; |
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} |
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static inline void verity_fec_dtr(struct dm_verity *v) |
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{ |
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} |
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static inline int verity_fec_ctr_alloc(struct dm_verity *v) |
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{ |
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return 0; |
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} |
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static inline int verity_fec_ctr(struct dm_verity *v) |
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{ |
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return 0; |
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} |
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#endif /* CONFIG_DM_VERITY_FEC */ |
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#endif /* DM_VERITY_FEC_H */
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