blob: 0f0eb8a3d922a212583ba491f3899a69a2b91bd6 [file] [log] [blame]
Sami Tolvanena739ff32015-12-03 14:26:30 +00001/*
2 * Copyright (C) 2015 Google, Inc.
3 *
4 * Author: Sami Tolvanen <samitolvanen@google.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 */
11
12#include "dm-verity-fec.h"
13#include <linux/math64.h>
14
15#define DM_MSG_PREFIX "verity-fec"
16
17/*
18 * If error correction has been configured, returns true.
19 */
20bool verity_fec_is_enabled(struct dm_verity *v)
21{
22 return v->fec && v->fec->dev;
23}
24
25/*
26 * Return a pointer to dm_verity_fec_io after dm_verity_io and its variable
27 * length fields.
28 */
29static inline struct dm_verity_fec_io *fec_io(struct dm_verity_io *io)
30{
31 return (struct dm_verity_fec_io *) verity_io_digest_end(io->v, io);
32}
33
34/*
35 * Return an interleaved offset for a byte in RS block.
36 */
37static inline u64 fec_interleave(struct dm_verity *v, u64 offset)
38{
39 u32 mod;
40
41 mod = do_div(offset, v->fec->rsn);
42 return offset + mod * (v->fec->rounds << v->data_dev_block_bits);
43}
44
45/*
46 * Decode an RS block using Reed-Solomon.
47 */
48static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
49 u8 *data, u8 *fec, int neras)
50{
51 int i;
52 uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
53
54 for (i = 0; i < v->fec->roots; i++)
55 par[i] = fec[i];
56
57 return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,
58 fio->erasures, 0, NULL);
59}
60
61/*
62 * Read error-correcting codes for the requested RS block. Returns a pointer
63 * to the data block. Caller is responsible for releasing buf.
64 */
65static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
66 unsigned *offset, struct dm_buffer **buf)
67{
68 u64 position, block;
69 u8 *res;
70
71 position = (index + rsb) * v->fec->roots;
72 block = position >> v->data_dev_block_bits;
73 *offset = (unsigned)(position - (block << v->data_dev_block_bits));
74
75 res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf);
76 if (unlikely(IS_ERR(res))) {
77 DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
78 v->data_dev->name, (unsigned long long)rsb,
79 (unsigned long long)(v->fec->start + block),
80 PTR_ERR(res));
81 *buf = NULL;
82 }
83
84 return res;
85}
86
87/* Loop over each preallocated buffer slot. */
88#define fec_for_each_prealloc_buffer(__i) \
89 for (__i = 0; __i < DM_VERITY_FEC_BUF_PREALLOC; __i++)
90
91/* Loop over each extra buffer slot. */
92#define fec_for_each_extra_buffer(io, __i) \
93 for (__i = DM_VERITY_FEC_BUF_PREALLOC; __i < DM_VERITY_FEC_BUF_MAX; __i++)
94
95/* Loop over each allocated buffer. */
96#define fec_for_each_buffer(io, __i) \
97 for (__i = 0; __i < (io)->nbufs; __i++)
98
99/* Loop over each RS block in each allocated buffer. */
100#define fec_for_each_buffer_rs_block(io, __i, __j) \
101 fec_for_each_buffer(io, __i) \
102 for (__j = 0; __j < 1 << DM_VERITY_FEC_BUF_RS_BITS; __j++)
103
104/*
105 * Return a pointer to the current RS block when called inside
106 * fec_for_each_buffer_rs_block.
107 */
108static inline u8 *fec_buffer_rs_block(struct dm_verity *v,
109 struct dm_verity_fec_io *fio,
110 unsigned i, unsigned j)
111{
112 return &fio->bufs[i][j * v->fec->rsn];
113}
114
115/*
116 * Return an index to the current RS block when called inside
117 * fec_for_each_buffer_rs_block.
118 */
119static inline unsigned fec_buffer_rs_index(unsigned i, unsigned j)
120{
121 return (i << DM_VERITY_FEC_BUF_RS_BITS) + j;
122}
123
124/*
125 * Decode all RS blocks from buffers and copy corrected bytes into fio->output
126 * starting from block_offset.
127 */
128static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio,
129 u64 rsb, int byte_index, unsigned block_offset,
130 int neras)
131{
132 int r, corrected = 0, res;
133 struct dm_buffer *buf;
134 unsigned n, i, offset;
135 u8 *par, *block;
136
137 par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
138 if (IS_ERR(par))
139 return PTR_ERR(par);
140
141 /*
142 * Decode the RS blocks we have in bufs. Each RS block results in
143 * one corrected target byte and consumes fec->roots parity bytes.
144 */
145 fec_for_each_buffer_rs_block(fio, n, i) {
146 block = fec_buffer_rs_block(v, fio, n, i);
147 res = fec_decode_rs8(v, fio, block, &par[offset], neras);
148 if (res < 0) {
149 dm_bufio_release(buf);
150
151 r = res;
152 goto error;
153 }
154
155 corrected += res;
156 fio->output[block_offset] = block[byte_index];
157
158 block_offset++;
159 if (block_offset >= 1 << v->data_dev_block_bits)
160 goto done;
161
162 /* read the next block when we run out of parity bytes */
163 offset += v->fec->roots;
164 if (offset >= 1 << v->data_dev_block_bits) {
165 dm_bufio_release(buf);
166
167 par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
168 if (unlikely(IS_ERR(par)))
169 return PTR_ERR(par);
170 }
171 }
172done:
173 r = corrected;
174error:
175 if (r < 0 && neras)
176 DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",
177 v->data_dev->name, (unsigned long long)rsb, r);
178 else if (r > 0)
179 DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",
180 v->data_dev->name, (unsigned long long)rsb, r);
181
182 return r;
183}
184
185/*
186 * Locate data block erasures using verity hashes.
187 */
188static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io,
189 u8 *want_digest, u8 *data)
190{
191 if (unlikely(verity_hash(v, verity_io_hash_desc(v, io),
192 data, 1 << v->data_dev_block_bits,
193 verity_io_real_digest(v, io))))
194 return 0;
195
196 return memcmp(verity_io_real_digest(v, io), want_digest,
197 v->digest_size) != 0;
198}
199
200/*
201 * Read data blocks that are part of the RS block and deinterleave as much as
202 * fits into buffers. Check for erasure locations if @neras is non-NULL.
203 */
204static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
205 u64 rsb, u64 target, unsigned block_offset,
206 int *neras)
207{
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000208 bool is_zero;
Sami Tolvanena739ff32015-12-03 14:26:30 +0000209 int i, j, target_index = -1;
210 struct dm_buffer *buf;
211 struct dm_bufio_client *bufio;
212 struct dm_verity_fec_io *fio = fec_io(io);
213 u64 block, ileaved;
214 u8 *bbuf, *rs_block;
215 u8 want_digest[v->digest_size];
216 unsigned n, k;
217
218 if (neras)
219 *neras = 0;
220
221 /*
222 * read each of the rsn data blocks that are part of the RS block, and
223 * interleave contents to available bufs
224 */
225 for (i = 0; i < v->fec->rsn; i++) {
226 ileaved = fec_interleave(v, rsb * v->fec->rsn + i);
227
228 /*
229 * target is the data block we want to correct, target_index is
230 * the index of this block within the rsn RS blocks
231 */
232 if (ileaved == target)
233 target_index = i;
234
235 block = ileaved >> v->data_dev_block_bits;
236 bufio = v->fec->data_bufio;
237
238 if (block >= v->data_blocks) {
239 block -= v->data_blocks;
240
241 /*
242 * blocks outside the area were assumed to contain
243 * zeros when encoding data was generated
244 */
245 if (unlikely(block >= v->fec->hash_blocks))
246 continue;
247
248 block += v->hash_start;
249 bufio = v->bufio;
250 }
251
252 bbuf = dm_bufio_read(bufio, block, &buf);
253 if (unlikely(IS_ERR(bbuf))) {
254 DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",
255 v->data_dev->name,
256 (unsigned long long)rsb,
257 (unsigned long long)block, PTR_ERR(bbuf));
258
259 /* assume the block is corrupted */
260 if (neras && *neras <= v->fec->roots)
261 fio->erasures[(*neras)++] = i;
262
263 continue;
264 }
265
266 /* locate erasures if the block is on the data device */
267 if (bufio == v->fec->data_bufio &&
Sami Tolvanen0cc37c22015-12-03 14:26:31 +0000268 verity_hash_for_block(v, io, block, want_digest,
269 &is_zero) == 0) {
270 /* skip known zero blocks entirely */
271 if (is_zero)
272 continue;
273
Sami Tolvanena739ff32015-12-03 14:26:30 +0000274 /*
275 * skip if we have already found the theoretical
276 * maximum number (i.e. fec->roots) of erasures
277 */
278 if (neras && *neras <= v->fec->roots &&
279 fec_is_erasure(v, io, want_digest, bbuf))
280 fio->erasures[(*neras)++] = i;
281 }
282
283 /*
284 * deinterleave and copy the bytes that fit into bufs,
285 * starting from block_offset
286 */
287 fec_for_each_buffer_rs_block(fio, n, j) {
288 k = fec_buffer_rs_index(n, j) + block_offset;
289
290 if (k >= 1 << v->data_dev_block_bits)
291 goto done;
292
293 rs_block = fec_buffer_rs_block(v, fio, n, j);
294 rs_block[i] = bbuf[k];
295 }
296done:
297 dm_bufio_release(buf);
298 }
299
300 return target_index;
301}
302
303/*
304 * Allocate RS control structure and FEC buffers from preallocated mempools,
305 * and attempt to allocate as many extra buffers as available.
306 */
307static int fec_alloc_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
308{
309 unsigned n;
310
311 if (!fio->rs) {
312 fio->rs = mempool_alloc(v->fec->rs_pool, 0);
313 if (unlikely(!fio->rs)) {
314 DMERR("failed to allocate RS");
315 return -ENOMEM;
316 }
317 }
318
319 fec_for_each_prealloc_buffer(n) {
320 if (fio->bufs[n])
321 continue;
322
323 fio->bufs[n] = mempool_alloc(v->fec->prealloc_pool, GFP_NOIO);
324 if (unlikely(!fio->bufs[n])) {
325 DMERR("failed to allocate FEC buffer");
326 return -ENOMEM;
327 }
328 }
329
330 /* try to allocate the maximum number of buffers */
331 fec_for_each_extra_buffer(fio, n) {
332 if (fio->bufs[n])
333 continue;
334
335 fio->bufs[n] = mempool_alloc(v->fec->extra_pool, GFP_NOIO);
336 /* we can manage with even one buffer if necessary */
337 if (unlikely(!fio->bufs[n]))
338 break;
339 }
340 fio->nbufs = n;
341
342 if (!fio->output) {
343 fio->output = mempool_alloc(v->fec->output_pool, GFP_NOIO);
344
345 if (!fio->output) {
346 DMERR("failed to allocate FEC page");
347 return -ENOMEM;
348 }
349 }
350
351 return 0;
352}
353
354/*
355 * Initialize buffers and clear erasures. fec_read_bufs() assumes buffers are
356 * zeroed before deinterleaving.
357 */
358static void fec_init_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
359{
360 unsigned n;
361
362 fec_for_each_buffer(fio, n)
363 memset(fio->bufs[n], 0, v->fec->rsn << DM_VERITY_FEC_BUF_RS_BITS);
364
365 memset(fio->erasures, 0, sizeof(fio->erasures));
366}
367
368/*
369 * Decode all RS blocks in a single data block and return the target block
370 * (indicated by @offset) in fio->output. If @use_erasures is non-zero, uses
371 * hashes to locate erasures.
372 */
373static int fec_decode_rsb(struct dm_verity *v, struct dm_verity_io *io,
374 struct dm_verity_fec_io *fio, u64 rsb, u64 offset,
375 bool use_erasures)
376{
377 int r, neras = 0;
378 unsigned pos;
379
380 r = fec_alloc_bufs(v, fio);
381 if (unlikely(r < 0))
382 return r;
383
384 for (pos = 0; pos < 1 << v->data_dev_block_bits; ) {
385 fec_init_bufs(v, fio);
386
387 r = fec_read_bufs(v, io, rsb, offset, pos,
388 use_erasures ? &neras : NULL);
389 if (unlikely(r < 0))
390 return r;
391
392 r = fec_decode_bufs(v, fio, rsb, r, pos, neras);
393 if (r < 0)
394 return r;
395
396 pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS;
397 }
398
399 /* Always re-validate the corrected block against the expected hash */
400 r = verity_hash(v, verity_io_hash_desc(v, io), fio->output,
401 1 << v->data_dev_block_bits,
402 verity_io_real_digest(v, io));
403 if (unlikely(r < 0))
404 return r;
405
406 if (memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io),
407 v->digest_size)) {
408 DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",
409 v->data_dev->name, (unsigned long long)rsb, neras);
410 return -EILSEQ;
411 }
412
413 return 0;
414}
415
416static int fec_bv_copy(struct dm_verity *v, struct dm_verity_io *io, u8 *data,
417 size_t len)
418{
419 struct dm_verity_fec_io *fio = fec_io(io);
420
421 memcpy(data, &fio->output[fio->output_pos], len);
422 fio->output_pos += len;
423
424 return 0;
425}
426
427/*
428 * Correct errors in a block. Copies corrected block to dest if non-NULL,
429 * otherwise to a bio_vec starting from iter.
430 */
431int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
432 enum verity_block_type type, sector_t block, u8 *dest,
433 struct bvec_iter *iter)
434{
435 int r;
436 struct dm_verity_fec_io *fio = fec_io(io);
437 u64 offset, res, rsb;
438
439 if (!verity_fec_is_enabled(v))
440 return -EOPNOTSUPP;
441
442 if (type == DM_VERITY_BLOCK_TYPE_METADATA)
443 block += v->data_blocks;
444
445 /*
446 * For RS(M, N), the continuous FEC data is divided into blocks of N
447 * bytes. Since block size may not be divisible by N, the last block
448 * is zero padded when decoding.
449 *
450 * Each byte of the block is covered by a different RS(M, N) code,
451 * and each code is interleaved over N blocks to make it less likely
452 * that bursty corruption will leave us in unrecoverable state.
453 */
454
455 offset = block << v->data_dev_block_bits;
Sami Tolvanen602d1652016-06-21 11:02:42 -0700456 res = div64_u64(offset, v->fec->rounds << v->data_dev_block_bits);
Sami Tolvanena739ff32015-12-03 14:26:30 +0000457
458 /*
459 * The base RS block we can feed to the interleaver to find out all
460 * blocks required for decoding.
461 */
462 rsb = offset - res * (v->fec->rounds << v->data_dev_block_bits);
463
464 /*
465 * Locating erasures is slow, so attempt to recover the block without
466 * them first. Do a second attempt with erasures if the corruption is
467 * bad enough.
468 */
469 r = fec_decode_rsb(v, io, fio, rsb, offset, false);
470 if (r < 0) {
471 r = fec_decode_rsb(v, io, fio, rsb, offset, true);
472 if (r < 0)
473 return r;
474 }
475
476 if (dest)
477 memcpy(dest, fio->output, 1 << v->data_dev_block_bits);
478 else if (iter) {
479 fio->output_pos = 0;
480 r = verity_for_bv_block(v, io, iter, fec_bv_copy);
481 }
482
483 return r;
484}
485
486/*
487 * Clean up per-bio data.
488 */
489void verity_fec_finish_io(struct dm_verity_io *io)
490{
491 unsigned n;
492 struct dm_verity_fec *f = io->v->fec;
493 struct dm_verity_fec_io *fio = fec_io(io);
494
495 if (!verity_fec_is_enabled(io->v))
496 return;
497
498 mempool_free(fio->rs, f->rs_pool);
499
500 fec_for_each_prealloc_buffer(n)
501 mempool_free(fio->bufs[n], f->prealloc_pool);
502
503 fec_for_each_extra_buffer(fio, n)
504 mempool_free(fio->bufs[n], f->extra_pool);
505
506 mempool_free(fio->output, f->output_pool);
507}
508
509/*
510 * Initialize per-bio data.
511 */
512void verity_fec_init_io(struct dm_verity_io *io)
513{
514 struct dm_verity_fec_io *fio = fec_io(io);
515
516 if (!verity_fec_is_enabled(io->v))
517 return;
518
519 fio->rs = NULL;
520 memset(fio->bufs, 0, sizeof(fio->bufs));
521 fio->nbufs = 0;
522 fio->output = NULL;
523}
524
525/*
526 * Append feature arguments and values to the status table.
527 */
528unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
529 char *result, unsigned maxlen)
530{
531 if (!verity_fec_is_enabled(v))
532 return sz;
533
534 DMEMIT(" " DM_VERITY_OPT_FEC_DEV " %s "
535 DM_VERITY_OPT_FEC_BLOCKS " %llu "
536 DM_VERITY_OPT_FEC_START " %llu "
537 DM_VERITY_OPT_FEC_ROOTS " %d",
538 v->fec->dev->name,
539 (unsigned long long)v->fec->blocks,
540 (unsigned long long)v->fec->start,
541 v->fec->roots);
542
543 return sz;
544}
545
546void verity_fec_dtr(struct dm_verity *v)
547{
548 struct dm_verity_fec *f = v->fec;
549
550 if (!verity_fec_is_enabled(v))
551 goto out;
552
553 mempool_destroy(f->rs_pool);
554 mempool_destroy(f->prealloc_pool);
555 mempool_destroy(f->extra_pool);
556 kmem_cache_destroy(f->cache);
557
558 if (f->data_bufio)
559 dm_bufio_client_destroy(f->data_bufio);
560 if (f->bufio)
561 dm_bufio_client_destroy(f->bufio);
562
563 if (f->dev)
564 dm_put_device(v->ti, f->dev);
565out:
566 kfree(f);
567 v->fec = NULL;
568}
569
570static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data)
571{
572 struct dm_verity *v = (struct dm_verity *)pool_data;
573
574 return init_rs(8, 0x11d, 0, 1, v->fec->roots);
575}
576
577static void fec_rs_free(void *element, void *pool_data)
578{
579 struct rs_control *rs = (struct rs_control *)element;
580
581 if (rs)
582 free_rs(rs);
583}
584
585bool verity_is_fec_opt_arg(const char *arg_name)
586{
587 return (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV) ||
588 !strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS) ||
589 !strcasecmp(arg_name, DM_VERITY_OPT_FEC_START) ||
590 !strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS));
591}
592
593int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
594 unsigned *argc, const char *arg_name)
595{
596 int r;
597 struct dm_target *ti = v->ti;
598 const char *arg_value;
599 unsigned long long num_ll;
600 unsigned char num_c;
601 char dummy;
602
603 if (!*argc) {
604 ti->error = "FEC feature arguments require a value";
605 return -EINVAL;
606 }
607
608 arg_value = dm_shift_arg(as);
609 (*argc)--;
610
611 if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {
612 r = dm_get_device(ti, arg_value, FMODE_READ, &v->fec->dev);
613 if (r) {
614 ti->error = "FEC device lookup failed";
615 return r;
616 }
617
618 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS)) {
619 if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
620 ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
621 >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
622 ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
623 return -EINVAL;
624 }
625 v->fec->blocks = num_ll;
626
627 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START)) {
628 if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
629 ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) >>
630 (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
631 ti->error = "Invalid " DM_VERITY_OPT_FEC_START;
632 return -EINVAL;
633 }
634 v->fec->start = num_ll;
635
636 } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) {
637 if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c ||
638 num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) ||
639 num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) {
640 ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS;
641 return -EINVAL;
642 }
643 v->fec->roots = num_c;
644
645 } else {
646 ti->error = "Unrecognized verity FEC feature request";
647 return -EINVAL;
648 }
649
650 return 0;
651}
652
653/*
654 * Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.
655 */
656int verity_fec_ctr_alloc(struct dm_verity *v)
657{
658 struct dm_verity_fec *f;
659
660 f = kzalloc(sizeof(struct dm_verity_fec), GFP_KERNEL);
661 if (!f) {
662 v->ti->error = "Cannot allocate FEC structure";
663 return -ENOMEM;
664 }
665 v->fec = f;
666
667 return 0;
668}
669
670/*
671 * Validate arguments and preallocate memory. Must be called after arguments
672 * have been parsed using verity_fec_parse_opt_args.
673 */
674int verity_fec_ctr(struct dm_verity *v)
675{
676 struct dm_verity_fec *f = v->fec;
677 struct dm_target *ti = v->ti;
678 u64 hash_blocks;
679
680 if (!verity_fec_is_enabled(v)) {
681 verity_fec_dtr(v);
682 return 0;
683 }
684
685 /*
686 * FEC is computed over data blocks, possible metadata, and
687 * hash blocks. In other words, FEC covers total of fec_blocks
688 * blocks consisting of the following:
689 *
690 * data blocks | hash blocks | metadata (optional)
691 *
692 * We allow metadata after hash blocks to support a use case
693 * where all data is stored on the same device and FEC covers
694 * the entire area.
695 *
696 * If metadata is included, we require it to be available on the
697 * hash device after the hash blocks.
698 */
699
700 hash_blocks = v->hash_blocks - v->hash_start;
701
702 /*
703 * Require matching block sizes for data and hash devices for
704 * simplicity.
705 */
706 if (v->data_dev_block_bits != v->hash_dev_block_bits) {
707 ti->error = "Block sizes must match to use FEC";
708 return -EINVAL;
709 }
710
711 if (!f->roots) {
712 ti->error = "Missing " DM_VERITY_OPT_FEC_ROOTS;
713 return -EINVAL;
714 }
715 f->rsn = DM_VERITY_FEC_RSM - f->roots;
716
717 if (!f->blocks) {
718 ti->error = "Missing " DM_VERITY_OPT_FEC_BLOCKS;
719 return -EINVAL;
720 }
721
722 f->rounds = f->blocks;
723 if (sector_div(f->rounds, f->rsn))
724 f->rounds++;
725
726 /*
727 * Due to optional metadata, f->blocks can be larger than
728 * data_blocks and hash_blocks combined.
729 */
730 if (f->blocks < v->data_blocks + hash_blocks || !f->rounds) {
731 ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
732 return -EINVAL;
733 }
734
735 /*
736 * Metadata is accessed through the hash device, so we require
737 * it to be large enough.
738 */
739 f->hash_blocks = f->blocks - v->data_blocks;
740 if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) {
741 ti->error = "Hash device is too small for "
742 DM_VERITY_OPT_FEC_BLOCKS;
743 return -E2BIG;
744 }
745
746 f->bufio = dm_bufio_client_create(f->dev->bdev,
747 1 << v->data_dev_block_bits,
748 1, 0, NULL, NULL);
749 if (IS_ERR(f->bufio)) {
750 ti->error = "Cannot initialize FEC bufio client";
751 return PTR_ERR(f->bufio);
752 }
753
754 if (dm_bufio_get_device_size(f->bufio) <
755 ((f->start + f->rounds * f->roots) >> v->data_dev_block_bits)) {
756 ti->error = "FEC device is too small";
757 return -E2BIG;
758 }
759
760 f->data_bufio = dm_bufio_client_create(v->data_dev->bdev,
761 1 << v->data_dev_block_bits,
762 1, 0, NULL, NULL);
763 if (IS_ERR(f->data_bufio)) {
764 ti->error = "Cannot initialize FEC data bufio client";
765 return PTR_ERR(f->data_bufio);
766 }
767
768 if (dm_bufio_get_device_size(f->data_bufio) < v->data_blocks) {
769 ti->error = "Data device is too small";
770 return -E2BIG;
771 }
772
773 /* Preallocate an rs_control structure for each worker thread */
774 f->rs_pool = mempool_create(num_online_cpus(), fec_rs_alloc,
775 fec_rs_free, (void *) v);
776 if (!f->rs_pool) {
777 ti->error = "Cannot allocate RS pool";
778 return -ENOMEM;
779 }
780
781 f->cache = kmem_cache_create("dm_verity_fec_buffers",
782 f->rsn << DM_VERITY_FEC_BUF_RS_BITS,
783 0, 0, NULL);
784 if (!f->cache) {
785 ti->error = "Cannot create FEC buffer cache";
786 return -ENOMEM;
787 }
788
789 /* Preallocate DM_VERITY_FEC_BUF_PREALLOC buffers for each thread */
790 f->prealloc_pool = mempool_create_slab_pool(num_online_cpus() *
791 DM_VERITY_FEC_BUF_PREALLOC,
792 f->cache);
793 if (!f->prealloc_pool) {
794 ti->error = "Cannot allocate FEC buffer prealloc pool";
795 return -ENOMEM;
796 }
797
798 f->extra_pool = mempool_create_slab_pool(0, f->cache);
799 if (!f->extra_pool) {
800 ti->error = "Cannot allocate FEC buffer extra pool";
801 return -ENOMEM;
802 }
803
804 /* Preallocate an output buffer for each thread */
805 f->output_pool = mempool_create_kmalloc_pool(num_online_cpus(),
806 1 << v->data_dev_block_bits);
807 if (!f->output_pool) {
808 ti->error = "Cannot allocate FEC output pool";
809 return -ENOMEM;
810 }
811
812 /* Reserve space for our per-bio data */
Mike Snitzer30187e12016-01-31 13:28:26 -0500813 ti->per_io_data_size += sizeof(struct dm_verity_fec_io);
Sami Tolvanena739ff32015-12-03 14:26:30 +0000814
815 return 0;
816}