xref: /linux/drivers/md/dm-crypt.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
1 /*
2  * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
3  * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
4  * Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
5  *
6  * This file is released under the GPL.
7  */
8 
9 #include <linux/completion.h>
10 #include <linux/err.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/bio.h>
15 #include <linux/blkdev.h>
16 #include <linux/mempool.h>
17 #include <linux/slab.h>
18 #include <linux/crypto.h>
19 #include <linux/workqueue.h>
20 #include <linux/backing-dev.h>
21 #include <asm/atomic.h>
22 #include <linux/scatterlist.h>
23 #include <asm/page.h>
24 #include <asm/unaligned.h>
25 
26 #include <linux/device-mapper.h>
27 
28 #define DM_MSG_PREFIX "crypt"
29 #define MESG_STR(x) x, sizeof(x)
30 
31 /*
32  * context holding the current state of a multi-part conversion
33  */
34 struct convert_context {
35 	struct completion restart;
36 	struct bio *bio_in;
37 	struct bio *bio_out;
38 	unsigned int offset_in;
39 	unsigned int offset_out;
40 	unsigned int idx_in;
41 	unsigned int idx_out;
42 	sector_t sector;
43 	atomic_t pending;
44 };
45 
46 /*
47  * per bio private data
48  */
49 struct dm_crypt_io {
50 	struct dm_target *target;
51 	struct bio *base_bio;
52 	struct work_struct work;
53 
54 	struct convert_context ctx;
55 
56 	atomic_t pending;
57 	int error;
58 	sector_t sector;
59 	struct dm_crypt_io *base_io;
60 };
61 
62 struct dm_crypt_request {
63 	struct convert_context *ctx;
64 	struct scatterlist sg_in;
65 	struct scatterlist sg_out;
66 };
67 
68 struct crypt_config;
69 
70 struct crypt_iv_operations {
71 	int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
72 		   const char *opts);
73 	void (*dtr)(struct crypt_config *cc);
74 	int (*init)(struct crypt_config *cc);
75 	int (*wipe)(struct crypt_config *cc);
76 	int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
77 };
78 
79 struct iv_essiv_private {
80 	struct crypto_cipher *tfm;
81 	struct crypto_hash *hash_tfm;
82 	u8 *salt;
83 };
84 
85 struct iv_benbi_private {
86 	int shift;
87 };
88 
89 /*
90  * Crypt: maps a linear range of a block device
91  * and encrypts / decrypts at the same time.
92  */
93 enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
94 struct crypt_config {
95 	struct dm_dev *dev;
96 	sector_t start;
97 
98 	/*
99 	 * pool for per bio private data, crypto requests and
100 	 * encryption requeusts/buffer pages
101 	 */
102 	mempool_t *io_pool;
103 	mempool_t *req_pool;
104 	mempool_t *page_pool;
105 	struct bio_set *bs;
106 
107 	struct workqueue_struct *io_queue;
108 	struct workqueue_struct *crypt_queue;
109 
110 	char *cipher;
111 	char *cipher_mode;
112 
113 	struct crypt_iv_operations *iv_gen_ops;
114 	union {
115 		struct iv_essiv_private essiv;
116 		struct iv_benbi_private benbi;
117 	} iv_gen_private;
118 	sector_t iv_offset;
119 	unsigned int iv_size;
120 
121 	/*
122 	 * Layout of each crypto request:
123 	 *
124 	 *   struct ablkcipher_request
125 	 *      context
126 	 *      padding
127 	 *   struct dm_crypt_request
128 	 *      padding
129 	 *   IV
130 	 *
131 	 * The padding is added so that dm_crypt_request and the IV are
132 	 * correctly aligned.
133 	 */
134 	unsigned int dmreq_start;
135 	struct ablkcipher_request *req;
136 
137 	struct crypto_ablkcipher *tfm;
138 	unsigned long flags;
139 	unsigned int key_size;
140 	u8 key[0];
141 };
142 
143 #define MIN_IOS        16
144 #define MIN_POOL_PAGES 32
145 #define MIN_BIO_PAGES  8
146 
147 static struct kmem_cache *_crypt_io_pool;
148 
149 static void clone_init(struct dm_crypt_io *, struct bio *);
150 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
151 
152 /*
153  * Different IV generation algorithms:
154  *
155  * plain: the initial vector is the 32-bit little-endian version of the sector
156  *        number, padded with zeros if necessary.
157  *
158  * plain64: the initial vector is the 64-bit little-endian version of the sector
159  *        number, padded with zeros if necessary.
160  *
161  * essiv: "encrypted sector|salt initial vector", the sector number is
162  *        encrypted with the bulk cipher using a salt as key. The salt
163  *        should be derived from the bulk cipher's key via hashing.
164  *
165  * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
166  *        (needed for LRW-32-AES and possible other narrow block modes)
167  *
168  * null: the initial vector is always zero.  Provides compatibility with
169  *       obsolete loop_fish2 devices.  Do not use for new devices.
170  *
171  * plumb: unimplemented, see:
172  * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
173  */
174 
175 static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
176 {
177 	memset(iv, 0, cc->iv_size);
178 	*(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
179 
180 	return 0;
181 }
182 
183 static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
184 				sector_t sector)
185 {
186 	memset(iv, 0, cc->iv_size);
187 	*(u64 *)iv = cpu_to_le64(sector);
188 
189 	return 0;
190 }
191 
192 /* Initialise ESSIV - compute salt but no local memory allocations */
193 static int crypt_iv_essiv_init(struct crypt_config *cc)
194 {
195 	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
196 	struct hash_desc desc;
197 	struct scatterlist sg;
198 	int err;
199 
200 	sg_init_one(&sg, cc->key, cc->key_size);
201 	desc.tfm = essiv->hash_tfm;
202 	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
203 
204 	err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
205 	if (err)
206 		return err;
207 
208 	return crypto_cipher_setkey(essiv->tfm, essiv->salt,
209 				    crypto_hash_digestsize(essiv->hash_tfm));
210 }
211 
212 /* Wipe salt and reset key derived from volume key */
213 static int crypt_iv_essiv_wipe(struct crypt_config *cc)
214 {
215 	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
216 	unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
217 
218 	memset(essiv->salt, 0, salt_size);
219 
220 	return crypto_cipher_setkey(essiv->tfm, essiv->salt, salt_size);
221 }
222 
223 static void crypt_iv_essiv_dtr(struct crypt_config *cc)
224 {
225 	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
226 
227 	crypto_free_cipher(essiv->tfm);
228 	essiv->tfm = NULL;
229 
230 	crypto_free_hash(essiv->hash_tfm);
231 	essiv->hash_tfm = NULL;
232 
233 	kzfree(essiv->salt);
234 	essiv->salt = NULL;
235 }
236 
237 static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
238 			      const char *opts)
239 {
240 	struct crypto_cipher *essiv_tfm = NULL;
241 	struct crypto_hash *hash_tfm = NULL;
242 	u8 *salt = NULL;
243 	int err;
244 
245 	if (!opts) {
246 		ti->error = "Digest algorithm missing for ESSIV mode";
247 		return -EINVAL;
248 	}
249 
250 	/* Allocate hash algorithm */
251 	hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
252 	if (IS_ERR(hash_tfm)) {
253 		ti->error = "Error initializing ESSIV hash";
254 		err = PTR_ERR(hash_tfm);
255 		goto bad;
256 	}
257 
258 	salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
259 	if (!salt) {
260 		ti->error = "Error kmallocing salt storage in ESSIV";
261 		err = -ENOMEM;
262 		goto bad;
263 	}
264 
265 	/* Allocate essiv_tfm */
266 	essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
267 	if (IS_ERR(essiv_tfm)) {
268 		ti->error = "Error allocating crypto tfm for ESSIV";
269 		err = PTR_ERR(essiv_tfm);
270 		goto bad;
271 	}
272 	if (crypto_cipher_blocksize(essiv_tfm) !=
273 	    crypto_ablkcipher_ivsize(cc->tfm)) {
274 		ti->error = "Block size of ESSIV cipher does "
275 			    "not match IV size of block cipher";
276 		err = -EINVAL;
277 		goto bad;
278 	}
279 
280 	cc->iv_gen_private.essiv.salt = salt;
281 	cc->iv_gen_private.essiv.tfm = essiv_tfm;
282 	cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
283 
284 	return 0;
285 
286 bad:
287 	if (essiv_tfm && !IS_ERR(essiv_tfm))
288 		crypto_free_cipher(essiv_tfm);
289 	if (hash_tfm && !IS_ERR(hash_tfm))
290 		crypto_free_hash(hash_tfm);
291 	kfree(salt);
292 	return err;
293 }
294 
295 static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
296 {
297 	memset(iv, 0, cc->iv_size);
298 	*(u64 *)iv = cpu_to_le64(sector);
299 	crypto_cipher_encrypt_one(cc->iv_gen_private.essiv.tfm, iv, iv);
300 	return 0;
301 }
302 
303 static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
304 			      const char *opts)
305 {
306 	unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
307 	int log = ilog2(bs);
308 
309 	/* we need to calculate how far we must shift the sector count
310 	 * to get the cipher block count, we use this shift in _gen */
311 
312 	if (1 << log != bs) {
313 		ti->error = "cypher blocksize is not a power of 2";
314 		return -EINVAL;
315 	}
316 
317 	if (log > 9) {
318 		ti->error = "cypher blocksize is > 512";
319 		return -EINVAL;
320 	}
321 
322 	cc->iv_gen_private.benbi.shift = 9 - log;
323 
324 	return 0;
325 }
326 
327 static void crypt_iv_benbi_dtr(struct crypt_config *cc)
328 {
329 }
330 
331 static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
332 {
333 	__be64 val;
334 
335 	memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
336 
337 	val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi.shift) + 1);
338 	put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
339 
340 	return 0;
341 }
342 
343 static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
344 {
345 	memset(iv, 0, cc->iv_size);
346 
347 	return 0;
348 }
349 
350 static struct crypt_iv_operations crypt_iv_plain_ops = {
351 	.generator = crypt_iv_plain_gen
352 };
353 
354 static struct crypt_iv_operations crypt_iv_plain64_ops = {
355 	.generator = crypt_iv_plain64_gen
356 };
357 
358 static struct crypt_iv_operations crypt_iv_essiv_ops = {
359 	.ctr       = crypt_iv_essiv_ctr,
360 	.dtr       = crypt_iv_essiv_dtr,
361 	.init      = crypt_iv_essiv_init,
362 	.wipe      = crypt_iv_essiv_wipe,
363 	.generator = crypt_iv_essiv_gen
364 };
365 
366 static struct crypt_iv_operations crypt_iv_benbi_ops = {
367 	.ctr	   = crypt_iv_benbi_ctr,
368 	.dtr	   = crypt_iv_benbi_dtr,
369 	.generator = crypt_iv_benbi_gen
370 };
371 
372 static struct crypt_iv_operations crypt_iv_null_ops = {
373 	.generator = crypt_iv_null_gen
374 };
375 
376 static void crypt_convert_init(struct crypt_config *cc,
377 			       struct convert_context *ctx,
378 			       struct bio *bio_out, struct bio *bio_in,
379 			       sector_t sector)
380 {
381 	ctx->bio_in = bio_in;
382 	ctx->bio_out = bio_out;
383 	ctx->offset_in = 0;
384 	ctx->offset_out = 0;
385 	ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
386 	ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
387 	ctx->sector = sector + cc->iv_offset;
388 	init_completion(&ctx->restart);
389 }
390 
391 static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
392 					     struct ablkcipher_request *req)
393 {
394 	return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
395 }
396 
397 static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
398 					       struct dm_crypt_request *dmreq)
399 {
400 	return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
401 }
402 
403 static int crypt_convert_block(struct crypt_config *cc,
404 			       struct convert_context *ctx,
405 			       struct ablkcipher_request *req)
406 {
407 	struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
408 	struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
409 	struct dm_crypt_request *dmreq;
410 	u8 *iv;
411 	int r = 0;
412 
413 	dmreq = dmreq_of_req(cc, req);
414 	iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
415 			 crypto_ablkcipher_alignmask(cc->tfm) + 1);
416 
417 	dmreq->ctx = ctx;
418 	sg_init_table(&dmreq->sg_in, 1);
419 	sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
420 		    bv_in->bv_offset + ctx->offset_in);
421 
422 	sg_init_table(&dmreq->sg_out, 1);
423 	sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
424 		    bv_out->bv_offset + ctx->offset_out);
425 
426 	ctx->offset_in += 1 << SECTOR_SHIFT;
427 	if (ctx->offset_in >= bv_in->bv_len) {
428 		ctx->offset_in = 0;
429 		ctx->idx_in++;
430 	}
431 
432 	ctx->offset_out += 1 << SECTOR_SHIFT;
433 	if (ctx->offset_out >= bv_out->bv_len) {
434 		ctx->offset_out = 0;
435 		ctx->idx_out++;
436 	}
437 
438 	if (cc->iv_gen_ops) {
439 		r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
440 		if (r < 0)
441 			return r;
442 	}
443 
444 	ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
445 				     1 << SECTOR_SHIFT, iv);
446 
447 	if (bio_data_dir(ctx->bio_in) == WRITE)
448 		r = crypto_ablkcipher_encrypt(req);
449 	else
450 		r = crypto_ablkcipher_decrypt(req);
451 
452 	return r;
453 }
454 
455 static void kcryptd_async_done(struct crypto_async_request *async_req,
456 			       int error);
457 static void crypt_alloc_req(struct crypt_config *cc,
458 			    struct convert_context *ctx)
459 {
460 	if (!cc->req)
461 		cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
462 	ablkcipher_request_set_tfm(cc->req, cc->tfm);
463 	ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
464 					CRYPTO_TFM_REQ_MAY_SLEEP,
465 					kcryptd_async_done,
466 					dmreq_of_req(cc, cc->req));
467 }
468 
469 /*
470  * Encrypt / decrypt data from one bio to another one (can be the same one)
471  */
472 static int crypt_convert(struct crypt_config *cc,
473 			 struct convert_context *ctx)
474 {
475 	int r;
476 
477 	atomic_set(&ctx->pending, 1);
478 
479 	while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
480 	      ctx->idx_out < ctx->bio_out->bi_vcnt) {
481 
482 		crypt_alloc_req(cc, ctx);
483 
484 		atomic_inc(&ctx->pending);
485 
486 		r = crypt_convert_block(cc, ctx, cc->req);
487 
488 		switch (r) {
489 		/* async */
490 		case -EBUSY:
491 			wait_for_completion(&ctx->restart);
492 			INIT_COMPLETION(ctx->restart);
493 			/* fall through*/
494 		case -EINPROGRESS:
495 			cc->req = NULL;
496 			ctx->sector++;
497 			continue;
498 
499 		/* sync */
500 		case 0:
501 			atomic_dec(&ctx->pending);
502 			ctx->sector++;
503 			cond_resched();
504 			continue;
505 
506 		/* error */
507 		default:
508 			atomic_dec(&ctx->pending);
509 			return r;
510 		}
511 	}
512 
513 	return 0;
514 }
515 
516 static void dm_crypt_bio_destructor(struct bio *bio)
517 {
518 	struct dm_crypt_io *io = bio->bi_private;
519 	struct crypt_config *cc = io->target->private;
520 
521 	bio_free(bio, cc->bs);
522 }
523 
524 /*
525  * Generate a new unfragmented bio with the given size
526  * This should never violate the device limitations
527  * May return a smaller bio when running out of pages, indicated by
528  * *out_of_pages set to 1.
529  */
530 static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
531 				      unsigned *out_of_pages)
532 {
533 	struct crypt_config *cc = io->target->private;
534 	struct bio *clone;
535 	unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
536 	gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
537 	unsigned i, len;
538 	struct page *page;
539 
540 	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
541 	if (!clone)
542 		return NULL;
543 
544 	clone_init(io, clone);
545 	*out_of_pages = 0;
546 
547 	for (i = 0; i < nr_iovecs; i++) {
548 		page = mempool_alloc(cc->page_pool, gfp_mask);
549 		if (!page) {
550 			*out_of_pages = 1;
551 			break;
552 		}
553 
554 		/*
555 		 * if additional pages cannot be allocated without waiting,
556 		 * return a partially allocated bio, the caller will then try
557 		 * to allocate additional bios while submitting this partial bio
558 		 */
559 		if (i == (MIN_BIO_PAGES - 1))
560 			gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
561 
562 		len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
563 
564 		if (!bio_add_page(clone, page, len, 0)) {
565 			mempool_free(page, cc->page_pool);
566 			break;
567 		}
568 
569 		size -= len;
570 	}
571 
572 	if (!clone->bi_size) {
573 		bio_put(clone);
574 		return NULL;
575 	}
576 
577 	return clone;
578 }
579 
580 static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
581 {
582 	unsigned int i;
583 	struct bio_vec *bv;
584 
585 	for (i = 0; i < clone->bi_vcnt; i++) {
586 		bv = bio_iovec_idx(clone, i);
587 		BUG_ON(!bv->bv_page);
588 		mempool_free(bv->bv_page, cc->page_pool);
589 		bv->bv_page = NULL;
590 	}
591 }
592 
593 static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
594 					  struct bio *bio, sector_t sector)
595 {
596 	struct crypt_config *cc = ti->private;
597 	struct dm_crypt_io *io;
598 
599 	io = mempool_alloc(cc->io_pool, GFP_NOIO);
600 	io->target = ti;
601 	io->base_bio = bio;
602 	io->sector = sector;
603 	io->error = 0;
604 	io->base_io = NULL;
605 	atomic_set(&io->pending, 0);
606 
607 	return io;
608 }
609 
610 static void crypt_inc_pending(struct dm_crypt_io *io)
611 {
612 	atomic_inc(&io->pending);
613 }
614 
615 /*
616  * One of the bios was finished. Check for completion of
617  * the whole request and correctly clean up the buffer.
618  * If base_io is set, wait for the last fragment to complete.
619  */
620 static void crypt_dec_pending(struct dm_crypt_io *io)
621 {
622 	struct crypt_config *cc = io->target->private;
623 	struct bio *base_bio = io->base_bio;
624 	struct dm_crypt_io *base_io = io->base_io;
625 	int error = io->error;
626 
627 	if (!atomic_dec_and_test(&io->pending))
628 		return;
629 
630 	mempool_free(io, cc->io_pool);
631 
632 	if (likely(!base_io))
633 		bio_endio(base_bio, error);
634 	else {
635 		if (error && !base_io->error)
636 			base_io->error = error;
637 		crypt_dec_pending(base_io);
638 	}
639 }
640 
641 /*
642  * kcryptd/kcryptd_io:
643  *
644  * Needed because it would be very unwise to do decryption in an
645  * interrupt context.
646  *
647  * kcryptd performs the actual encryption or decryption.
648  *
649  * kcryptd_io performs the IO submission.
650  *
651  * They must be separated as otherwise the final stages could be
652  * starved by new requests which can block in the first stages due
653  * to memory allocation.
654  */
655 static void crypt_endio(struct bio *clone, int error)
656 {
657 	struct dm_crypt_io *io = clone->bi_private;
658 	struct crypt_config *cc = io->target->private;
659 	unsigned rw = bio_data_dir(clone);
660 
661 	if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
662 		error = -EIO;
663 
664 	/*
665 	 * free the processed pages
666 	 */
667 	if (rw == WRITE)
668 		crypt_free_buffer_pages(cc, clone);
669 
670 	bio_put(clone);
671 
672 	if (rw == READ && !error) {
673 		kcryptd_queue_crypt(io);
674 		return;
675 	}
676 
677 	if (unlikely(error))
678 		io->error = error;
679 
680 	crypt_dec_pending(io);
681 }
682 
683 static void clone_init(struct dm_crypt_io *io, struct bio *clone)
684 {
685 	struct crypt_config *cc = io->target->private;
686 
687 	clone->bi_private = io;
688 	clone->bi_end_io  = crypt_endio;
689 	clone->bi_bdev    = cc->dev->bdev;
690 	clone->bi_rw      = io->base_bio->bi_rw;
691 	clone->bi_destructor = dm_crypt_bio_destructor;
692 }
693 
694 static void kcryptd_io_read(struct dm_crypt_io *io)
695 {
696 	struct crypt_config *cc = io->target->private;
697 	struct bio *base_bio = io->base_bio;
698 	struct bio *clone;
699 
700 	crypt_inc_pending(io);
701 
702 	/*
703 	 * The block layer might modify the bvec array, so always
704 	 * copy the required bvecs because we need the original
705 	 * one in order to decrypt the whole bio data *afterwards*.
706 	 */
707 	clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
708 	if (unlikely(!clone)) {
709 		io->error = -ENOMEM;
710 		crypt_dec_pending(io);
711 		return;
712 	}
713 
714 	clone_init(io, clone);
715 	clone->bi_idx = 0;
716 	clone->bi_vcnt = bio_segments(base_bio);
717 	clone->bi_size = base_bio->bi_size;
718 	clone->bi_sector = cc->start + io->sector;
719 	memcpy(clone->bi_io_vec, bio_iovec(base_bio),
720 	       sizeof(struct bio_vec) * clone->bi_vcnt);
721 
722 	generic_make_request(clone);
723 }
724 
725 static void kcryptd_io_write(struct dm_crypt_io *io)
726 {
727 	struct bio *clone = io->ctx.bio_out;
728 	generic_make_request(clone);
729 }
730 
731 static void kcryptd_io(struct work_struct *work)
732 {
733 	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
734 
735 	if (bio_data_dir(io->base_bio) == READ)
736 		kcryptd_io_read(io);
737 	else
738 		kcryptd_io_write(io);
739 }
740 
741 static void kcryptd_queue_io(struct dm_crypt_io *io)
742 {
743 	struct crypt_config *cc = io->target->private;
744 
745 	INIT_WORK(&io->work, kcryptd_io);
746 	queue_work(cc->io_queue, &io->work);
747 }
748 
749 static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
750 					  int error, int async)
751 {
752 	struct bio *clone = io->ctx.bio_out;
753 	struct crypt_config *cc = io->target->private;
754 
755 	if (unlikely(error < 0)) {
756 		crypt_free_buffer_pages(cc, clone);
757 		bio_put(clone);
758 		io->error = -EIO;
759 		crypt_dec_pending(io);
760 		return;
761 	}
762 
763 	/* crypt_convert should have filled the clone bio */
764 	BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
765 
766 	clone->bi_sector = cc->start + io->sector;
767 
768 	if (async)
769 		kcryptd_queue_io(io);
770 	else
771 		generic_make_request(clone);
772 }
773 
774 static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
775 {
776 	struct crypt_config *cc = io->target->private;
777 	struct bio *clone;
778 	struct dm_crypt_io *new_io;
779 	int crypt_finished;
780 	unsigned out_of_pages = 0;
781 	unsigned remaining = io->base_bio->bi_size;
782 	sector_t sector = io->sector;
783 	int r;
784 
785 	/*
786 	 * Prevent io from disappearing until this function completes.
787 	 */
788 	crypt_inc_pending(io);
789 	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
790 
791 	/*
792 	 * The allocated buffers can be smaller than the whole bio,
793 	 * so repeat the whole process until all the data can be handled.
794 	 */
795 	while (remaining) {
796 		clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
797 		if (unlikely(!clone)) {
798 			io->error = -ENOMEM;
799 			break;
800 		}
801 
802 		io->ctx.bio_out = clone;
803 		io->ctx.idx_out = 0;
804 
805 		remaining -= clone->bi_size;
806 		sector += bio_sectors(clone);
807 
808 		crypt_inc_pending(io);
809 		r = crypt_convert(cc, &io->ctx);
810 		crypt_finished = atomic_dec_and_test(&io->ctx.pending);
811 
812 		/* Encryption was already finished, submit io now */
813 		if (crypt_finished) {
814 			kcryptd_crypt_write_io_submit(io, r, 0);
815 
816 			/*
817 			 * If there was an error, do not try next fragments.
818 			 * For async, error is processed in async handler.
819 			 */
820 			if (unlikely(r < 0))
821 				break;
822 
823 			io->sector = sector;
824 		}
825 
826 		/*
827 		 * Out of memory -> run queues
828 		 * But don't wait if split was due to the io size restriction
829 		 */
830 		if (unlikely(out_of_pages))
831 			congestion_wait(BLK_RW_ASYNC, HZ/100);
832 
833 		/*
834 		 * With async crypto it is unsafe to share the crypto context
835 		 * between fragments, so switch to a new dm_crypt_io structure.
836 		 */
837 		if (unlikely(!crypt_finished && remaining)) {
838 			new_io = crypt_io_alloc(io->target, io->base_bio,
839 						sector);
840 			crypt_inc_pending(new_io);
841 			crypt_convert_init(cc, &new_io->ctx, NULL,
842 					   io->base_bio, sector);
843 			new_io->ctx.idx_in = io->ctx.idx_in;
844 			new_io->ctx.offset_in = io->ctx.offset_in;
845 
846 			/*
847 			 * Fragments after the first use the base_io
848 			 * pending count.
849 			 */
850 			if (!io->base_io)
851 				new_io->base_io = io;
852 			else {
853 				new_io->base_io = io->base_io;
854 				crypt_inc_pending(io->base_io);
855 				crypt_dec_pending(io);
856 			}
857 
858 			io = new_io;
859 		}
860 	}
861 
862 	crypt_dec_pending(io);
863 }
864 
865 static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
866 {
867 	if (unlikely(error < 0))
868 		io->error = -EIO;
869 
870 	crypt_dec_pending(io);
871 }
872 
873 static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
874 {
875 	struct crypt_config *cc = io->target->private;
876 	int r = 0;
877 
878 	crypt_inc_pending(io);
879 
880 	crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
881 			   io->sector);
882 
883 	r = crypt_convert(cc, &io->ctx);
884 
885 	if (atomic_dec_and_test(&io->ctx.pending))
886 		kcryptd_crypt_read_done(io, r);
887 
888 	crypt_dec_pending(io);
889 }
890 
891 static void kcryptd_async_done(struct crypto_async_request *async_req,
892 			       int error)
893 {
894 	struct dm_crypt_request *dmreq = async_req->data;
895 	struct convert_context *ctx = dmreq->ctx;
896 	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
897 	struct crypt_config *cc = io->target->private;
898 
899 	if (error == -EINPROGRESS) {
900 		complete(&ctx->restart);
901 		return;
902 	}
903 
904 	mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
905 
906 	if (!atomic_dec_and_test(&ctx->pending))
907 		return;
908 
909 	if (bio_data_dir(io->base_bio) == READ)
910 		kcryptd_crypt_read_done(io, error);
911 	else
912 		kcryptd_crypt_write_io_submit(io, error, 1);
913 }
914 
915 static void kcryptd_crypt(struct work_struct *work)
916 {
917 	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
918 
919 	if (bio_data_dir(io->base_bio) == READ)
920 		kcryptd_crypt_read_convert(io);
921 	else
922 		kcryptd_crypt_write_convert(io);
923 }
924 
925 static void kcryptd_queue_crypt(struct dm_crypt_io *io)
926 {
927 	struct crypt_config *cc = io->target->private;
928 
929 	INIT_WORK(&io->work, kcryptd_crypt);
930 	queue_work(cc->crypt_queue, &io->work);
931 }
932 
933 /*
934  * Decode key from its hex representation
935  */
936 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
937 {
938 	char buffer[3];
939 	char *endp;
940 	unsigned int i;
941 
942 	buffer[2] = '\0';
943 
944 	for (i = 0; i < size; i++) {
945 		buffer[0] = *hex++;
946 		buffer[1] = *hex++;
947 
948 		key[i] = (u8)simple_strtoul(buffer, &endp, 16);
949 
950 		if (endp != &buffer[2])
951 			return -EINVAL;
952 	}
953 
954 	if (*hex != '\0')
955 		return -EINVAL;
956 
957 	return 0;
958 }
959 
960 /*
961  * Encode key into its hex representation
962  */
963 static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
964 {
965 	unsigned int i;
966 
967 	for (i = 0; i < size; i++) {
968 		sprintf(hex, "%02x", *key);
969 		hex += 2;
970 		key++;
971 	}
972 }
973 
974 static int crypt_set_key(struct crypt_config *cc, char *key)
975 {
976 	unsigned key_size = strlen(key) >> 1;
977 
978 	if (cc->key_size && cc->key_size != key_size)
979 		return -EINVAL;
980 
981 	cc->key_size = key_size; /* initial settings */
982 
983 	if ((!key_size && strcmp(key, "-")) ||
984 	   (key_size && crypt_decode_key(cc->key, key, key_size) < 0))
985 		return -EINVAL;
986 
987 	set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
988 
989 	return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
990 }
991 
992 static int crypt_wipe_key(struct crypt_config *cc)
993 {
994 	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
995 	memset(&cc->key, 0, cc->key_size * sizeof(u8));
996 	return crypto_ablkcipher_setkey(cc->tfm, cc->key, cc->key_size);
997 }
998 
999 static void crypt_dtr(struct dm_target *ti)
1000 {
1001 	struct crypt_config *cc = ti->private;
1002 
1003 	ti->private = NULL;
1004 
1005 	if (!cc)
1006 		return;
1007 
1008 	if (cc->io_queue)
1009 		destroy_workqueue(cc->io_queue);
1010 	if (cc->crypt_queue)
1011 		destroy_workqueue(cc->crypt_queue);
1012 
1013 	if (cc->bs)
1014 		bioset_free(cc->bs);
1015 
1016 	if (cc->page_pool)
1017 		mempool_destroy(cc->page_pool);
1018 	if (cc->req_pool)
1019 		mempool_destroy(cc->req_pool);
1020 	if (cc->io_pool)
1021 		mempool_destroy(cc->io_pool);
1022 
1023 	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
1024 		cc->iv_gen_ops->dtr(cc);
1025 
1026 	if (cc->tfm && !IS_ERR(cc->tfm))
1027 		crypto_free_ablkcipher(cc->tfm);
1028 
1029 	if (cc->dev)
1030 		dm_put_device(ti, cc->dev);
1031 
1032 	kzfree(cc->cipher);
1033 	kzfree(cc->cipher_mode);
1034 
1035 	/* Must zero key material before freeing */
1036 	kzfree(cc);
1037 }
1038 
1039 static int crypt_ctr_cipher(struct dm_target *ti,
1040 			    char *cipher_in, char *key)
1041 {
1042 	struct crypt_config *cc = ti->private;
1043 	char *tmp, *cipher, *chainmode, *ivmode, *ivopts;
1044 	char *cipher_api = NULL;
1045 	int ret = -EINVAL;
1046 
1047 	/* Convert to crypto api definition? */
1048 	if (strchr(cipher_in, '(')) {
1049 		ti->error = "Bad cipher specification";
1050 		return -EINVAL;
1051 	}
1052 
1053 	/*
1054 	 * Legacy dm-crypt cipher specification
1055 	 * cipher-mode-iv:ivopts
1056 	 */
1057 	tmp = cipher_in;
1058 	cipher = strsep(&tmp, "-");
1059 
1060 	cc->cipher = kstrdup(cipher, GFP_KERNEL);
1061 	if (!cc->cipher)
1062 		goto bad_mem;
1063 
1064 	if (tmp) {
1065 		cc->cipher_mode = kstrdup(tmp, GFP_KERNEL);
1066 		if (!cc->cipher_mode)
1067 			goto bad_mem;
1068 	}
1069 
1070 	chainmode = strsep(&tmp, "-");
1071 	ivopts = strsep(&tmp, "-");
1072 	ivmode = strsep(&ivopts, ":");
1073 
1074 	if (tmp)
1075 		DMWARN("Ignoring unexpected additional cipher options");
1076 
1077 	/* Compatibility mode for old dm-crypt mappings */
1078 	if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
1079 		kfree(cc->cipher_mode);
1080 		cc->cipher_mode = kstrdup("cbc-plain", GFP_KERNEL);
1081 		chainmode = "cbc";
1082 		ivmode = "plain";
1083 	}
1084 
1085 	if (strcmp(chainmode, "ecb") && !ivmode) {
1086 		ti->error = "IV mechanism required";
1087 		return -EINVAL;
1088 	}
1089 
1090 	cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
1091 	if (!cipher_api)
1092 		goto bad_mem;
1093 
1094 	ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
1095 		       "%s(%s)", chainmode, cipher);
1096 	if (ret < 0) {
1097 		kfree(cipher_api);
1098 		goto bad_mem;
1099 	}
1100 
1101 	/* Allocate cipher */
1102 	cc->tfm = crypto_alloc_ablkcipher(cipher_api, 0, 0);
1103 	if (IS_ERR(cc->tfm)) {
1104 		ret = PTR_ERR(cc->tfm);
1105 		ti->error = "Error allocating crypto tfm";
1106 		goto bad;
1107 	}
1108 
1109 	/* Initialize and set key */
1110 	ret = crypt_set_key(cc, key);
1111 	if (ret < 0) {
1112 		ti->error = "Error decoding and setting key";
1113 		goto bad;
1114 	}
1115 
1116 	/* Initialize IV */
1117 	cc->iv_size = crypto_ablkcipher_ivsize(cc->tfm);
1118 	if (cc->iv_size)
1119 		/* at least a 64 bit sector number should fit in our buffer */
1120 		cc->iv_size = max(cc->iv_size,
1121 				  (unsigned int)(sizeof(u64) / sizeof(u8)));
1122 	else if (ivmode) {
1123 		DMWARN("Selected cipher does not support IVs");
1124 		ivmode = NULL;
1125 	}
1126 
1127 	/* Choose ivmode, see comments at iv code. */
1128 	if (ivmode == NULL)
1129 		cc->iv_gen_ops = NULL;
1130 	else if (strcmp(ivmode, "plain") == 0)
1131 		cc->iv_gen_ops = &crypt_iv_plain_ops;
1132 	else if (strcmp(ivmode, "plain64") == 0)
1133 		cc->iv_gen_ops = &crypt_iv_plain64_ops;
1134 	else if (strcmp(ivmode, "essiv") == 0)
1135 		cc->iv_gen_ops = &crypt_iv_essiv_ops;
1136 	else if (strcmp(ivmode, "benbi") == 0)
1137 		cc->iv_gen_ops = &crypt_iv_benbi_ops;
1138 	else if (strcmp(ivmode, "null") == 0)
1139 		cc->iv_gen_ops = &crypt_iv_null_ops;
1140 	else {
1141 		ret = -EINVAL;
1142 		ti->error = "Invalid IV mode";
1143 		goto bad;
1144 	}
1145 
1146 	/* Allocate IV */
1147 	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
1148 		ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
1149 		if (ret < 0) {
1150 			ti->error = "Error creating IV";
1151 			goto bad;
1152 		}
1153 	}
1154 
1155 	/* Initialize IV (set keys for ESSIV etc) */
1156 	if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
1157 		ret = cc->iv_gen_ops->init(cc);
1158 		if (ret < 0) {
1159 			ti->error = "Error initialising IV";
1160 			goto bad;
1161 		}
1162 	}
1163 
1164 	ret = 0;
1165 bad:
1166 	kfree(cipher_api);
1167 	return ret;
1168 
1169 bad_mem:
1170 	ti->error = "Cannot allocate cipher strings";
1171 	return -ENOMEM;
1172 }
1173 
1174 /*
1175  * Construct an encryption mapping:
1176  * <cipher> <key> <iv_offset> <dev_path> <start>
1177  */
1178 static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1179 {
1180 	struct crypt_config *cc;
1181 	unsigned int key_size;
1182 	unsigned long long tmpll;
1183 	int ret;
1184 
1185 	if (argc != 5) {
1186 		ti->error = "Not enough arguments";
1187 		return -EINVAL;
1188 	}
1189 
1190 	key_size = strlen(argv[1]) >> 1;
1191 
1192 	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
1193 	if (!cc) {
1194 		ti->error = "Cannot allocate encryption context";
1195 		return -ENOMEM;
1196 	}
1197 
1198 	ti->private = cc;
1199 	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
1200 	if (ret < 0)
1201 		goto bad;
1202 
1203 	ret = -ENOMEM;
1204 	cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
1205 	if (!cc->io_pool) {
1206 		ti->error = "Cannot allocate crypt io mempool";
1207 		goto bad;
1208 	}
1209 
1210 	cc->dmreq_start = sizeof(struct ablkcipher_request);
1211 	cc->dmreq_start += crypto_ablkcipher_reqsize(cc->tfm);
1212 	cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
1213 	cc->dmreq_start += crypto_ablkcipher_alignmask(cc->tfm) &
1214 			   ~(crypto_tfm_ctx_alignment() - 1);
1215 
1216 	cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
1217 			sizeof(struct dm_crypt_request) + cc->iv_size);
1218 	if (!cc->req_pool) {
1219 		ti->error = "Cannot allocate crypt request mempool";
1220 		goto bad;
1221 	}
1222 	cc->req = NULL;
1223 
1224 	cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
1225 	if (!cc->page_pool) {
1226 		ti->error = "Cannot allocate page mempool";
1227 		goto bad;
1228 	}
1229 
1230 	cc->bs = bioset_create(MIN_IOS, 0);
1231 	if (!cc->bs) {
1232 		ti->error = "Cannot allocate crypt bioset";
1233 		goto bad;
1234 	}
1235 
1236 	ret = -EINVAL;
1237 	if (sscanf(argv[2], "%llu", &tmpll) != 1) {
1238 		ti->error = "Invalid iv_offset sector";
1239 		goto bad;
1240 	}
1241 	cc->iv_offset = tmpll;
1242 
1243 	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
1244 		ti->error = "Device lookup failed";
1245 		goto bad;
1246 	}
1247 
1248 	if (sscanf(argv[4], "%llu", &tmpll) != 1) {
1249 		ti->error = "Invalid device sector";
1250 		goto bad;
1251 	}
1252 	cc->start = tmpll;
1253 
1254 	ret = -ENOMEM;
1255 	cc->io_queue = create_singlethread_workqueue("kcryptd_io");
1256 	if (!cc->io_queue) {
1257 		ti->error = "Couldn't create kcryptd io queue";
1258 		goto bad;
1259 	}
1260 
1261 	cc->crypt_queue = create_singlethread_workqueue("kcryptd");
1262 	if (!cc->crypt_queue) {
1263 		ti->error = "Couldn't create kcryptd queue";
1264 		goto bad;
1265 	}
1266 
1267 	ti->num_flush_requests = 1;
1268 	return 0;
1269 
1270 bad:
1271 	crypt_dtr(ti);
1272 	return ret;
1273 }
1274 
1275 static int crypt_map(struct dm_target *ti, struct bio *bio,
1276 		     union map_info *map_context)
1277 {
1278 	struct dm_crypt_io *io;
1279 	struct crypt_config *cc;
1280 
1281 	if (unlikely(bio_empty_barrier(bio))) {
1282 		cc = ti->private;
1283 		bio->bi_bdev = cc->dev->bdev;
1284 		return DM_MAPIO_REMAPPED;
1285 	}
1286 
1287 	io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
1288 
1289 	if (bio_data_dir(io->base_bio) == READ)
1290 		kcryptd_queue_io(io);
1291 	else
1292 		kcryptd_queue_crypt(io);
1293 
1294 	return DM_MAPIO_SUBMITTED;
1295 }
1296 
1297 static int crypt_status(struct dm_target *ti, status_type_t type,
1298 			char *result, unsigned int maxlen)
1299 {
1300 	struct crypt_config *cc = ti->private;
1301 	unsigned int sz = 0;
1302 
1303 	switch (type) {
1304 	case STATUSTYPE_INFO:
1305 		result[0] = '\0';
1306 		break;
1307 
1308 	case STATUSTYPE_TABLE:
1309 		if (cc->cipher_mode)
1310 			DMEMIT("%s-%s ", cc->cipher, cc->cipher_mode);
1311 		else
1312 			DMEMIT("%s ", cc->cipher);
1313 
1314 		if (cc->key_size > 0) {
1315 			if ((maxlen - sz) < ((cc->key_size << 1) + 1))
1316 				return -ENOMEM;
1317 
1318 			crypt_encode_key(result + sz, cc->key, cc->key_size);
1319 			sz += cc->key_size << 1;
1320 		} else {
1321 			if (sz >= maxlen)
1322 				return -ENOMEM;
1323 			result[sz++] = '-';
1324 		}
1325 
1326 		DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
1327 				cc->dev->name, (unsigned long long)cc->start);
1328 		break;
1329 	}
1330 	return 0;
1331 }
1332 
1333 static void crypt_postsuspend(struct dm_target *ti)
1334 {
1335 	struct crypt_config *cc = ti->private;
1336 
1337 	set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1338 }
1339 
1340 static int crypt_preresume(struct dm_target *ti)
1341 {
1342 	struct crypt_config *cc = ti->private;
1343 
1344 	if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
1345 		DMERR("aborting resume - crypt key is not set.");
1346 		return -EAGAIN;
1347 	}
1348 
1349 	return 0;
1350 }
1351 
1352 static void crypt_resume(struct dm_target *ti)
1353 {
1354 	struct crypt_config *cc = ti->private;
1355 
1356 	clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
1357 }
1358 
1359 /* Message interface
1360  *	key set <key>
1361  *	key wipe
1362  */
1363 static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
1364 {
1365 	struct crypt_config *cc = ti->private;
1366 	int ret = -EINVAL;
1367 
1368 	if (argc < 2)
1369 		goto error;
1370 
1371 	if (!strnicmp(argv[0], MESG_STR("key"))) {
1372 		if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
1373 			DMWARN("not suspended during key manipulation.");
1374 			return -EINVAL;
1375 		}
1376 		if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) {
1377 			ret = crypt_set_key(cc, argv[2]);
1378 			if (ret)
1379 				return ret;
1380 			if (cc->iv_gen_ops && cc->iv_gen_ops->init)
1381 				ret = cc->iv_gen_ops->init(cc);
1382 			return ret;
1383 		}
1384 		if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) {
1385 			if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
1386 				ret = cc->iv_gen_ops->wipe(cc);
1387 				if (ret)
1388 					return ret;
1389 			}
1390 			return crypt_wipe_key(cc);
1391 		}
1392 	}
1393 
1394 error:
1395 	DMWARN("unrecognised message received.");
1396 	return -EINVAL;
1397 }
1398 
1399 static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
1400 		       struct bio_vec *biovec, int max_size)
1401 {
1402 	struct crypt_config *cc = ti->private;
1403 	struct request_queue *q = bdev_get_queue(cc->dev->bdev);
1404 
1405 	if (!q->merge_bvec_fn)
1406 		return max_size;
1407 
1408 	bvm->bi_bdev = cc->dev->bdev;
1409 	bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
1410 
1411 	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
1412 }
1413 
1414 static int crypt_iterate_devices(struct dm_target *ti,
1415 				 iterate_devices_callout_fn fn, void *data)
1416 {
1417 	struct crypt_config *cc = ti->private;
1418 
1419 	return fn(ti, cc->dev, cc->start, ti->len, data);
1420 }
1421 
1422 static struct target_type crypt_target = {
1423 	.name   = "crypt",
1424 	.version = {1, 7, 0},
1425 	.module = THIS_MODULE,
1426 	.ctr    = crypt_ctr,
1427 	.dtr    = crypt_dtr,
1428 	.map    = crypt_map,
1429 	.status = crypt_status,
1430 	.postsuspend = crypt_postsuspend,
1431 	.preresume = crypt_preresume,
1432 	.resume = crypt_resume,
1433 	.message = crypt_message,
1434 	.merge  = crypt_merge,
1435 	.iterate_devices = crypt_iterate_devices,
1436 };
1437 
1438 static int __init dm_crypt_init(void)
1439 {
1440 	int r;
1441 
1442 	_crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
1443 	if (!_crypt_io_pool)
1444 		return -ENOMEM;
1445 
1446 	r = dm_register_target(&crypt_target);
1447 	if (r < 0) {
1448 		DMERR("register failed %d", r);
1449 		kmem_cache_destroy(_crypt_io_pool);
1450 	}
1451 
1452 	return r;
1453 }
1454 
1455 static void __exit dm_crypt_exit(void)
1456 {
1457 	dm_unregister_target(&crypt_target);
1458 	kmem_cache_destroy(_crypt_io_pool);
1459 }
1460 
1461 module_init(dm_crypt_init);
1462 module_exit(dm_crypt_exit);
1463 
1464 MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
1465 MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
1466 MODULE_LICENSE("GPL");
1467