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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (C) 2015 Google, Inc.4 *5 * Author: Sami Tolvanen <samitolvanen@google.com>6 */7 8#include "dm-verity-fec.h"9#include <linux/math64.h>10 11#define DM_MSG_PREFIX "verity-fec"12 13/*14 * If error correction has been configured, returns true.15 */16bool verity_fec_is_enabled(struct dm_verity *v)17{18 return v->fec && v->fec->dev;19}20 21/*22 * Return a pointer to dm_verity_fec_io after dm_verity_io and its variable23 * length fields.24 */25static inline struct dm_verity_fec_io *fec_io(struct dm_verity_io *io)26{27 return (struct dm_verity_fec_io *)28 ((char *)io + io->v->ti->per_io_data_size - sizeof(struct dm_verity_fec_io));29}30 31/*32 * Return an interleaved offset for a byte in RS block.33 */34static inline u64 fec_interleave(struct dm_verity *v, u64 offset)35{36 u32 mod;37 38 mod = do_div(offset, v->fec->rsn);39 return offset + mod * (v->fec->rounds << v->data_dev_block_bits);40}41 42/*43 * Decode an RS block using Reed-Solomon.44 */45static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,46 u8 *data, u8 *fec, int neras)47{48 int i;49 uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];50 51 for (i = 0; i < v->fec->roots; i++)52 par[i] = fec[i];53 54 return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,55 fio->erasures, 0, NULL);56}57 58/*59 * Read error-correcting codes for the requested RS block. Returns a pointer60 * to the data block. Caller is responsible for releasing buf.61 */62static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,63 unsigned int *offset, struct dm_buffer **buf,64 unsigned short ioprio)65{66 u64 position, block, rem;67 u8 *res;68 69 position = (index + rsb) * v->fec->roots;70 block = div64_u64_rem(position, v->fec->io_size, &rem);71 *offset = (unsigned int)rem;72 73 res = dm_bufio_read_with_ioprio(v->fec->bufio, block, buf, ioprio);74 if (IS_ERR(res)) {75 DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",76 v->data_dev->name, (unsigned long long)rsb,77 (unsigned long long)block, PTR_ERR(res));78 *buf = NULL;79 }80 81 return res;82}83 84/* Loop over each preallocated buffer slot. */85#define fec_for_each_prealloc_buffer(__i) \86 for (__i = 0; __i < DM_VERITY_FEC_BUF_PREALLOC; __i++)87 88/* Loop over each extra buffer slot. */89#define fec_for_each_extra_buffer(io, __i) \90 for (__i = DM_VERITY_FEC_BUF_PREALLOC; __i < DM_VERITY_FEC_BUF_MAX; __i++)91 92/* Loop over each allocated buffer. */93#define fec_for_each_buffer(io, __i) \94 for (__i = 0; __i < (io)->nbufs; __i++)95 96/* Loop over each RS block in each allocated buffer. */97#define fec_for_each_buffer_rs_block(io, __i, __j) \98 fec_for_each_buffer(io, __i) \99 for (__j = 0; __j < 1 << DM_VERITY_FEC_BUF_RS_BITS; __j++)100 101/*102 * Return a pointer to the current RS block when called inside103 * fec_for_each_buffer_rs_block.104 */105static inline u8 *fec_buffer_rs_block(struct dm_verity *v,106 struct dm_verity_fec_io *fio,107 unsigned int i, unsigned int j)108{109 return &fio->bufs[i][j * v->fec->rsn];110}111 112/*113 * Return an index to the current RS block when called inside114 * fec_for_each_buffer_rs_block.115 */116static inline unsigned int fec_buffer_rs_index(unsigned int i, unsigned int j)117{118 return (i << DM_VERITY_FEC_BUF_RS_BITS) + j;119}120 121/*122 * Decode all RS blocks from buffers and copy corrected bytes into fio->output123 * starting from block_offset.124 */125static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io,126 struct dm_verity_fec_io *fio, u64 rsb, int byte_index,127 unsigned int block_offset, int neras)128{129 int r, corrected = 0, res;130 struct dm_buffer *buf;131 unsigned int n, i, offset;132 u8 *par, *block;133 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);134 135 par = fec_read_parity(v, rsb, block_offset, &offset, &buf, bio_prio(bio));136 if (IS_ERR(par))137 return PTR_ERR(par);138 139 /*140 * Decode the RS blocks we have in bufs. Each RS block results in141 * one corrected target byte and consumes fec->roots parity bytes.142 */143 fec_for_each_buffer_rs_block(fio, n, i) {144 block = fec_buffer_rs_block(v, fio, n, i);145 res = fec_decode_rs8(v, fio, block, &par[offset], neras);146 if (res < 0) {147 r = res;148 goto error;149 }150 151 corrected += res;152 fio->output[block_offset] = block[byte_index];153 154 block_offset++;155 if (block_offset >= 1 << v->data_dev_block_bits)156 goto done;157 158 /* read the next block when we run out of parity bytes */159 offset += v->fec->roots;160 if (offset >= v->fec->io_size) {161 dm_bufio_release(buf);162 163 par = fec_read_parity(v, rsb, block_offset, &offset, &buf, bio_prio(bio));164 if (IS_ERR(par))165 return PTR_ERR(par);166 }167 }168done:169 r = corrected;170error:171 dm_bufio_release(buf);172 173 if (r < 0 && neras)174 DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",175 v->data_dev->name, (unsigned long long)rsb, r);176 else if (r > 0)177 DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",178 v->data_dev->name, (unsigned long long)rsb, r);179 180 return r;181}182 183/*184 * Locate data block erasures using verity hashes.185 */186static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io,187 u8 *want_digest, u8 *data)188{189 if (unlikely(verity_hash(v, io, data, 1 << v->data_dev_block_bits,190 verity_io_real_digest(v, io), true)))191 return 0;192 193 return memcmp(verity_io_real_digest(v, io), want_digest,194 v->digest_size) != 0;195}196 197/*198 * Read data blocks that are part of the RS block and deinterleave as much as199 * fits into buffers. Check for erasure locations if @neras is non-NULL.200 */201static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,202 u64 rsb, u64 target, unsigned int block_offset,203 int *neras)204{205 bool is_zero;206 int i, j, target_index = -1;207 struct dm_buffer *buf;208 struct dm_bufio_client *bufio;209 struct dm_verity_fec_io *fio = fec_io(io);210 u64 block, ileaved;211 u8 *bbuf, *rs_block;212 u8 want_digest[HASH_MAX_DIGESTSIZE];213 unsigned int n, k;214 struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);215 216 if (neras)217 *neras = 0;218 219 if (WARN_ON(v->digest_size > sizeof(want_digest)))220 return -EINVAL;221 222 /*223 * read each of the rsn data blocks that are part of the RS block, and224 * interleave contents to available bufs225 */226 for (i = 0; i < v->fec->rsn; i++) {227 ileaved = fec_interleave(v, rsb * v->fec->rsn + i);228 229 /*230 * target is the data block we want to correct, target_index is231 * the index of this block within the rsn RS blocks232 */233 if (ileaved == target)234 target_index = i;235 236 block = ileaved >> v->data_dev_block_bits;237 bufio = v->fec->data_bufio;238 239 if (block >= v->data_blocks) {240 block -= v->data_blocks;241 242 /*243 * blocks outside the area were assumed to contain244 * zeros when encoding data was generated245 */246 if (unlikely(block >= v->fec->hash_blocks))247 continue;248 249 block += v->hash_start;250 bufio = v->bufio;251 }252 253 bbuf = dm_bufio_read_with_ioprio(bufio, block, &buf, bio_prio(bio));254 if (IS_ERR(bbuf)) {255 DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",256 v->data_dev->name,257 (unsigned long long)rsb,258 (unsigned long long)block, PTR_ERR(bbuf));259 260 /* assume the block is corrupted */261 if (neras && *neras <= v->fec->roots)262 fio->erasures[(*neras)++] = i;263 264 continue;265 }266 267 /* locate erasures if the block is on the data device */268 if (bufio == v->fec->data_bufio &&269 verity_hash_for_block(v, io, block, want_digest,270 &is_zero) == 0) {271 /* skip known zero blocks entirely */272 if (is_zero)273 goto done;274 275 /*276 * skip if we have already found the theoretical277 * maximum number (i.e. fec->roots) of erasures278 */279 if (neras && *neras <= v->fec->roots &&280 fec_is_erasure(v, io, want_digest, bbuf))281 fio->erasures[(*neras)++] = i;282 }283 284 /*285 * deinterleave and copy the bytes that fit into bufs,286 * starting from block_offset287 */288 fec_for_each_buffer_rs_block(fio, n, j) {289 k = fec_buffer_rs_index(n, j) + block_offset;290 291 if (k >= 1 << v->data_dev_block_bits)292 goto done;293 294 rs_block = fec_buffer_rs_block(v, fio, n, j);295 rs_block[i] = bbuf[k];296 }297done:298 dm_bufio_release(buf);299 }300 301 return target_index;302}303 304/*305 * Allocate RS control structure and FEC buffers from preallocated mempools,306 * and attempt to allocate as many extra buffers as available.307 */308static int fec_alloc_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)309{310 unsigned int n;311 312 if (!fio->rs)313 fio->rs = mempool_alloc(&v->fec->rs_pool, GFP_NOIO);314 315 fec_for_each_prealloc_buffer(n) {316 if (fio->bufs[n])317 continue;318 319 fio->bufs[n] = mempool_alloc(&v->fec->prealloc_pool, GFP_NOWAIT);320 if (unlikely(!fio->bufs[n])) {321 DMERR("failed to allocate FEC buffer");322 return -ENOMEM;323 }324 }325 326 /* try to allocate the maximum number of buffers */327 fec_for_each_extra_buffer(fio, n) {328 if (fio->bufs[n])329 continue;330 331 fio->bufs[n] = mempool_alloc(&v->fec->extra_pool, GFP_NOWAIT);332 /* we can manage with even one buffer if necessary */333 if (unlikely(!fio->bufs[n]))334 break;335 }336 fio->nbufs = n;337 338 if (!fio->output)339 fio->output = mempool_alloc(&v->fec->output_pool, GFP_NOIO);340 341 return 0;342}343 344/*345 * Initialize buffers and clear erasures. fec_read_bufs() assumes buffers are346 * zeroed before deinterleaving.347 */348static void fec_init_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)349{350 unsigned int n;351 352 fec_for_each_buffer(fio, n)353 memset(fio->bufs[n], 0, v->fec->rsn << DM_VERITY_FEC_BUF_RS_BITS);354 355 memset(fio->erasures, 0, sizeof(fio->erasures));356}357 358/*359 * Decode all RS blocks in a single data block and return the target block360 * (indicated by @offset) in fio->output. If @use_erasures is non-zero, uses361 * hashes to locate erasures.362 */363static int fec_decode_rsb(struct dm_verity *v, struct dm_verity_io *io,364 struct dm_verity_fec_io *fio, u64 rsb, u64 offset,365 bool use_erasures)366{367 int r, neras = 0;368 unsigned int pos;369 370 r = fec_alloc_bufs(v, fio);371 if (unlikely(r < 0))372 return r;373 374 for (pos = 0; pos < 1 << v->data_dev_block_bits; ) {375 fec_init_bufs(v, fio);376 377 r = fec_read_bufs(v, io, rsb, offset, pos,378 use_erasures ? &neras : NULL);379 if (unlikely(r < 0))380 return r;381 382 r = fec_decode_bufs(v, io, fio, rsb, r, pos, neras);383 if (r < 0)384 return r;385 386 pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS;387 }388 389 /* Always re-validate the corrected block against the expected hash */390 r = verity_hash(v, io, fio->output, 1 << v->data_dev_block_bits,391 verity_io_real_digest(v, io), true);392 if (unlikely(r < 0))393 return r;394 395 if (memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io),396 v->digest_size)) {397 DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",398 v->data_dev->name, (unsigned long long)rsb, neras);399 return -EILSEQ;400 }401 402 return 0;403}404 405/* Correct errors in a block. Copies corrected block to dest. */406int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,407 enum verity_block_type type, sector_t block, u8 *dest)408{409 int r;410 struct dm_verity_fec_io *fio = fec_io(io);411 u64 offset, res, rsb;412 413 if (!verity_fec_is_enabled(v))414 return -EOPNOTSUPP;415 416 if (fio->level >= DM_VERITY_FEC_MAX_RECURSION) {417 DMWARN_LIMIT("%s: FEC: recursion too deep", v->data_dev->name);418 return -EIO;419 }420 421 fio->level++;422 423 if (type == DM_VERITY_BLOCK_TYPE_METADATA)424 block = block - v->hash_start + v->data_blocks;425 426 /*427 * For RS(M, N), the continuous FEC data is divided into blocks of N428 * bytes. Since block size may not be divisible by N, the last block429 * is zero padded when decoding.430 *431 * Each byte of the block is covered by a different RS(M, N) code,432 * and each code is interleaved over N blocks to make it less likely433 * that bursty corruption will leave us in unrecoverable state.434 */435 436 offset = block << v->data_dev_block_bits;437 res = div64_u64(offset, v->fec->rounds << v->data_dev_block_bits);438 439 /*440 * The base RS block we can feed to the interleaver to find out all441 * blocks required for decoding.442 */443 rsb = offset - res * (v->fec->rounds << v->data_dev_block_bits);444 445 /*446 * Locating erasures is slow, so attempt to recover the block without447 * them first. Do a second attempt with erasures if the corruption is448 * bad enough.449 */450 r = fec_decode_rsb(v, io, fio, rsb, offset, false);451 if (r < 0) {452 r = fec_decode_rsb(v, io, fio, rsb, offset, true);453 if (r < 0)454 goto done;455 }456 457 memcpy(dest, fio->output, 1 << v->data_dev_block_bits);458 459done:460 fio->level--;461 return r;462}463 464/*465 * Clean up per-bio data.466 */467void verity_fec_finish_io(struct dm_verity_io *io)468{469 unsigned int n;470 struct dm_verity_fec *f = io->v->fec;471 struct dm_verity_fec_io *fio = fec_io(io);472 473 if (!verity_fec_is_enabled(io->v))474 return;475 476 mempool_free(fio->rs, &f->rs_pool);477 478 fec_for_each_prealloc_buffer(n)479 mempool_free(fio->bufs[n], &f->prealloc_pool);480 481 fec_for_each_extra_buffer(fio, n)482 mempool_free(fio->bufs[n], &f->extra_pool);483 484 mempool_free(fio->output, &f->output_pool);485}486 487/*488 * Initialize per-bio data.489 */490void verity_fec_init_io(struct dm_verity_io *io)491{492 struct dm_verity_fec_io *fio = fec_io(io);493 494 if (!verity_fec_is_enabled(io->v))495 return;496 497 fio->rs = NULL;498 memset(fio->bufs, 0, sizeof(fio->bufs));499 fio->nbufs = 0;500 fio->output = NULL;501 fio->level = 0;502}503 504/*505 * Append feature arguments and values to the status table.506 */507unsigned int verity_fec_status_table(struct dm_verity *v, unsigned int sz,508 char *result, unsigned int maxlen)509{510 if (!verity_fec_is_enabled(v))511 return sz;512 513 DMEMIT(" " DM_VERITY_OPT_FEC_DEV " %s "514 DM_VERITY_OPT_FEC_BLOCKS " %llu "515 DM_VERITY_OPT_FEC_START " %llu "516 DM_VERITY_OPT_FEC_ROOTS " %d",517 v->fec->dev->name,518 (unsigned long long)v->fec->blocks,519 (unsigned long long)v->fec->start,520 v->fec->roots);521 522 return sz;523}524 525void verity_fec_dtr(struct dm_verity *v)526{527 struct dm_verity_fec *f = v->fec;528 529 if (!verity_fec_is_enabled(v))530 goto out;531 532 mempool_exit(&f->rs_pool);533 mempool_exit(&f->prealloc_pool);534 mempool_exit(&f->extra_pool);535 mempool_exit(&f->output_pool);536 kmem_cache_destroy(f->cache);537 538 if (f->data_bufio)539 dm_bufio_client_destroy(f->data_bufio);540 if (f->bufio)541 dm_bufio_client_destroy(f->bufio);542 543 if (f->dev)544 dm_put_device(v->ti, f->dev);545out:546 kfree(f);547 v->fec = NULL;548}549 550static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data)551{552 struct dm_verity *v = pool_data;553 554 return init_rs_gfp(8, 0x11d, 0, 1, v->fec->roots, gfp_mask);555}556 557static void fec_rs_free(void *element, void *pool_data)558{559 struct rs_control *rs = element;560 561 if (rs)562 free_rs(rs);563}564 565bool verity_is_fec_opt_arg(const char *arg_name)566{567 return (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV) ||568 !strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS) ||569 !strcasecmp(arg_name, DM_VERITY_OPT_FEC_START) ||570 !strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS));571}572 573int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,574 unsigned int *argc, const char *arg_name)575{576 int r;577 struct dm_target *ti = v->ti;578 const char *arg_value;579 unsigned long long num_ll;580 unsigned char num_c;581 char dummy;582 583 if (!*argc) {584 ti->error = "FEC feature arguments require a value";585 return -EINVAL;586 }587 588 arg_value = dm_shift_arg(as);589 (*argc)--;590 591 if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {592 r = dm_get_device(ti, arg_value, BLK_OPEN_READ, &v->fec->dev);593 if (r) {594 ti->error = "FEC device lookup failed";595 return r;596 }597 598 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS)) {599 if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||600 ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))601 >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {602 ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;603 return -EINVAL;604 }605 v->fec->blocks = num_ll;606 607 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START)) {608 if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||609 ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) >>610 (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {611 ti->error = "Invalid " DM_VERITY_OPT_FEC_START;612 return -EINVAL;613 }614 v->fec->start = num_ll;615 616 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) {617 if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c ||618 num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) ||619 num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) {620 ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS;621 return -EINVAL;622 }623 v->fec->roots = num_c;624 625 } else {626 ti->error = "Unrecognized verity FEC feature request";627 return -EINVAL;628 }629 630 return 0;631}632 633/*634 * Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.635 */636int verity_fec_ctr_alloc(struct dm_verity *v)637{638 struct dm_verity_fec *f;639 640 f = kzalloc(sizeof(struct dm_verity_fec), GFP_KERNEL);641 if (!f) {642 v->ti->error = "Cannot allocate FEC structure";643 return -ENOMEM;644 }645 v->fec = f;646 647 return 0;648}649 650/*651 * Validate arguments and preallocate memory. Must be called after arguments652 * have been parsed using verity_fec_parse_opt_args.653 */654int verity_fec_ctr(struct dm_verity *v)655{656 struct dm_verity_fec *f = v->fec;657 struct dm_target *ti = v->ti;658 u64 hash_blocks, fec_blocks;659 int ret;660 661 if (!verity_fec_is_enabled(v)) {662 verity_fec_dtr(v);663 return 0;664 }665 666 /*667 * FEC is computed over data blocks, possible metadata, and668 * hash blocks. In other words, FEC covers total of fec_blocks669 * blocks consisting of the following:670 *671 * data blocks | hash blocks | metadata (optional)672 *673 * We allow metadata after hash blocks to support a use case674 * where all data is stored on the same device and FEC covers675 * the entire area.676 *677 * If metadata is included, we require it to be available on the678 * hash device after the hash blocks.679 */680 681 hash_blocks = v->hash_blocks - v->hash_start;682 683 /*684 * Require matching block sizes for data and hash devices for685 * simplicity.686 */687 if (v->data_dev_block_bits != v->hash_dev_block_bits) {688 ti->error = "Block sizes must match to use FEC";689 return -EINVAL;690 }691 692 if (!f->roots) {693 ti->error = "Missing " DM_VERITY_OPT_FEC_ROOTS;694 return -EINVAL;695 }696 f->rsn = DM_VERITY_FEC_RSM - f->roots;697 698 if (!f->blocks) {699 ti->error = "Missing " DM_VERITY_OPT_FEC_BLOCKS;700 return -EINVAL;701 }702 703 f->rounds = f->blocks;704 if (sector_div(f->rounds, f->rsn))705 f->rounds++;706 707 /*708 * Due to optional metadata, f->blocks can be larger than709 * data_blocks and hash_blocks combined.710 */711 if (f->blocks < v->data_blocks + hash_blocks || !f->rounds) {712 ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;713 return -EINVAL;714 }715 716 /*717 * Metadata is accessed through the hash device, so we require718 * it to be large enough.719 */720 f->hash_blocks = f->blocks - v->data_blocks;721 if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) {722 ti->error = "Hash device is too small for "723 DM_VERITY_OPT_FEC_BLOCKS;724 return -E2BIG;725 }726 727 if ((f->roots << SECTOR_SHIFT) & ((1 << v->data_dev_block_bits) - 1))728 f->io_size = 1 << v->data_dev_block_bits;729 else730 f->io_size = v->fec->roots << SECTOR_SHIFT;731 732 f->bufio = dm_bufio_client_create(f->dev->bdev,733 f->io_size,734 1, 0, NULL, NULL, 0);735 if (IS_ERR(f->bufio)) {736 ti->error = "Cannot initialize FEC bufio client";737 return PTR_ERR(f->bufio);738 }739 740 dm_bufio_set_sector_offset(f->bufio, f->start << (v->data_dev_block_bits - SECTOR_SHIFT));741 742 fec_blocks = div64_u64(f->rounds * f->roots, v->fec->roots << SECTOR_SHIFT);743 if (dm_bufio_get_device_size(f->bufio) < fec_blocks) {744 ti->error = "FEC device is too small";745 return -E2BIG;746 }747 748 f->data_bufio = dm_bufio_client_create(v->data_dev->bdev,749 1 << v->data_dev_block_bits,750 1, 0, NULL, NULL, 0);751 if (IS_ERR(f->data_bufio)) {752 ti->error = "Cannot initialize FEC data bufio client";753 return PTR_ERR(f->data_bufio);754 }755 756 if (dm_bufio_get_device_size(f->data_bufio) < v->data_blocks) {757 ti->error = "Data device is too small";758 return -E2BIG;759 }760 761 /* Preallocate an rs_control structure for each worker thread */762 ret = mempool_init(&f->rs_pool, num_online_cpus(), fec_rs_alloc,763 fec_rs_free, (void *) v);764 if (ret) {765 ti->error = "Cannot allocate RS pool";766 return ret;767 }768 769 f->cache = kmem_cache_create("dm_verity_fec_buffers",770 f->rsn << DM_VERITY_FEC_BUF_RS_BITS,771 0, 0, NULL);772 if (!f->cache) {773 ti->error = "Cannot create FEC buffer cache";774 return -ENOMEM;775 }776 777 /* Preallocate DM_VERITY_FEC_BUF_PREALLOC buffers for each thread */778 ret = mempool_init_slab_pool(&f->prealloc_pool, num_online_cpus() *779 DM_VERITY_FEC_BUF_PREALLOC,780 f->cache);781 if (ret) {782 ti->error = "Cannot allocate FEC buffer prealloc pool";783 return ret;784 }785 786 ret = mempool_init_slab_pool(&f->extra_pool, 0, f->cache);787 if (ret) {788 ti->error = "Cannot allocate FEC buffer extra pool";789 return ret;790 }791 792 /* Preallocate an output buffer for each thread */793 ret = mempool_init_kmalloc_pool(&f->output_pool, num_online_cpus(),794 1 << v->data_dev_block_bits);795 if (ret) {796 ti->error = "Cannot allocate FEC output pool";797 return ret;798 }799 800 /* Reserve space for our per-bio data */801 ti->per_io_data_size += sizeof(struct dm_verity_fec_io);802 803 return 0;804}805