[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit

Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/drivers/md/dm-crypt.c b/ap/os/linux/linux-3.4.x/drivers/md/dm-crypt.c
new file mode 100644
index 0000000..a1bd688
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/md/dm-crypt.c
@@ -0,0 +1,1905 @@
+/*
+ * Copyright (C) 2003 Christophe Saout <christophe@saout.de>
+ * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
+ * Copyright (C) 2006-2009 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/mempool.h>
+#include <linux/slab.h>
+#include <linux/crypto.h>
+#include <linux/workqueue.h>
+#include <linux/backing-dev.h>
+#include <linux/percpu.h>
+#include <linux/atomic.h>
+#include <linux/scatterlist.h>
+#include <asm/page.h>
+#include <asm/unaligned.h>
+#include <crypto/hash.h>
+#include <crypto/md5.h>
+#include <crypto/algapi.h>
+
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "crypt"
+
+/*
+ * context holding the current state of a multi-part conversion
+ */
+struct convert_context {
+	struct completion restart;
+	struct bio *bio_in;
+	struct bio *bio_out;
+	unsigned int offset_in;
+	unsigned int offset_out;
+	unsigned int idx_in;
+	unsigned int idx_out;
+	sector_t sector;
+	atomic_t pending;
+};
+
+/*
+ * per bio private data
+ */
+struct dm_crypt_io {
+	struct dm_target *target;
+	struct bio *base_bio;
+	struct work_struct work;
+
+	struct convert_context ctx;
+
+	atomic_t pending;
+	int error;
+	sector_t sector;
+	struct dm_crypt_io *base_io;
+};
+
+struct dm_crypt_request {
+	struct convert_context *ctx;
+	struct scatterlist sg_in;
+	struct scatterlist sg_out;
+	sector_t iv_sector;
+};
+
+struct crypt_config;
+
+struct crypt_iv_operations {
+	int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
+		   const char *opts);
+	void (*dtr)(struct crypt_config *cc);
+	int (*init)(struct crypt_config *cc);
+	int (*wipe)(struct crypt_config *cc);
+	int (*generator)(struct crypt_config *cc, u8 *iv,
+			 struct dm_crypt_request *dmreq);
+	int (*post)(struct crypt_config *cc, u8 *iv,
+		    struct dm_crypt_request *dmreq);
+};
+
+struct iv_essiv_private {
+	struct crypto_hash *hash_tfm;
+	u8 *salt;
+};
+
+struct iv_benbi_private {
+	int shift;
+};
+
+#define LMK_SEED_SIZE 64 /* hash + 0 */
+struct iv_lmk_private {
+	struct crypto_shash *hash_tfm;
+	u8 *seed;
+};
+
+/*
+ * Crypt: maps a linear range of a block device
+ * and encrypts / decrypts at the same time.
+ */
+enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
+
+/*
+ * Duplicated per-CPU state for cipher.
+ */
+struct crypt_cpu {
+	struct ablkcipher_request *req;
+	/* ESSIV: struct crypto_cipher *essiv_tfm */
+	void *iv_private;
+	struct crypto_ablkcipher *tfms[0];
+};
+
+/*
+ * The fields in here must be read only after initialization,
+ * changing state should be in crypt_cpu.
+ */
+struct crypt_config {
+	struct dm_dev *dev;
+	sector_t start;
+
+	/*
+	 * pool for per bio private data, crypto requests and
+	 * encryption requeusts/buffer pages
+	 */
+	mempool_t *io_pool;
+	mempool_t *req_pool;
+	mempool_t *page_pool;
+	struct bio_set *bs;
+
+	struct workqueue_struct *io_queue;
+	struct workqueue_struct *crypt_queue;
+
+	char *cipher;
+	char *cipher_string;
+
+	struct crypt_iv_operations *iv_gen_ops;
+	union {
+		struct iv_essiv_private essiv;
+		struct iv_benbi_private benbi;
+		struct iv_lmk_private lmk;
+	} iv_gen_private;
+	sector_t iv_offset;
+	unsigned int iv_size;
+
+	/*
+	 * Duplicated per cpu state. Access through
+	 * per_cpu_ptr() only.
+	 */
+	struct crypt_cpu __percpu *cpu;
+	unsigned tfms_count;
+
+	/*
+	 * Layout of each crypto request:
+	 *
+	 *   struct ablkcipher_request
+	 *      context
+	 *      padding
+	 *   struct dm_crypt_request
+	 *      padding
+	 *   IV
+	 *
+	 * The padding is added so that dm_crypt_request and the IV are
+	 * correctly aligned.
+	 */
+	unsigned int dmreq_start;
+
+	unsigned long flags;
+	unsigned int key_size;
+	unsigned int key_parts;
+	u8 key[0];
+};
+
+#define MIN_IOS        16
+#define MIN_POOL_PAGES 32
+
+static struct kmem_cache *_crypt_io_pool;
+
+static void clone_init(struct dm_crypt_io *, struct bio *);
+static void kcryptd_queue_crypt(struct dm_crypt_io *io);
+static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
+
+static struct crypt_cpu *this_crypt_config(struct crypt_config *cc)
+{
+	return this_cpu_ptr(cc->cpu);
+}
+
+/*
+ * Use this to access cipher attributes that are the same for each CPU.
+ */
+static struct crypto_ablkcipher *any_tfm(struct crypt_config *cc)
+{
+	return __this_cpu_ptr(cc->cpu)->tfms[0];
+}
+
+/*
+ * Different IV generation algorithms:
+ *
+ * plain: the initial vector is the 32-bit little-endian version of the sector
+ *        number, padded with zeros if necessary.
+ *
+ * plain64: the initial vector is the 64-bit little-endian version of the sector
+ *        number, padded with zeros if necessary.
+ *
+ * essiv: "encrypted sector|salt initial vector", the sector number is
+ *        encrypted with the bulk cipher using a salt as key. The salt
+ *        should be derived from the bulk cipher's key via hashing.
+ *
+ * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
+ *        (needed for LRW-32-AES and possible other narrow block modes)
+ *
+ * null: the initial vector is always zero.  Provides compatibility with
+ *       obsolete loop_fish2 devices.  Do not use for new devices.
+ *
+ * lmk:  Compatible implementation of the block chaining mode used
+ *       by the Loop-AES block device encryption system
+ *       designed by Jari Ruusu. See http://loop-aes.sourceforge.net/
+ *       It operates on full 512 byte sectors and uses CBC
+ *       with an IV derived from the sector number, the data and
+ *       optionally extra IV seed.
+ *       This means that after decryption the first block
+ *       of sector must be tweaked according to decrypted data.
+ *       Loop-AES can use three encryption schemes:
+ *         version 1: is plain aes-cbc mode
+ *         version 2: uses 64 multikey scheme with lmk IV generator
+ *         version 3: the same as version 2 with additional IV seed
+ *                   (it uses 65 keys, last key is used as IV seed)
+ *
+ * plumb: unimplemented, see:
+ * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
+ */
+
+static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv,
+			      struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+	*(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff);
+
+	return 0;
+}
+
+static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv,
+				struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+	*(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
+
+	return 0;
+}
+
+/* Initialise ESSIV - compute salt but no local memory allocations */
+static int crypt_iv_essiv_init(struct crypt_config *cc)
+{
+	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+	struct hash_desc desc;
+	struct scatterlist sg;
+	struct crypto_cipher *essiv_tfm;
+	int err, cpu;
+
+	sg_init_one(&sg, cc->key, cc->key_size);
+	desc.tfm = essiv->hash_tfm;
+	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	err = crypto_hash_digest(&desc, &sg, cc->key_size, essiv->salt);
+	if (err)
+		return err;
+
+	for_each_possible_cpu(cpu) {
+		essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private,
+
+		err = crypto_cipher_setkey(essiv_tfm, essiv->salt,
+				    crypto_hash_digestsize(essiv->hash_tfm));
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+/* Wipe salt and reset key derived from volume key */
+static int crypt_iv_essiv_wipe(struct crypt_config *cc)
+{
+	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+	unsigned salt_size = crypto_hash_digestsize(essiv->hash_tfm);
+	struct crypto_cipher *essiv_tfm;
+	int cpu, r, err = 0;
+
+	memset(essiv->salt, 0, salt_size);
+
+	for_each_possible_cpu(cpu) {
+		essiv_tfm = per_cpu_ptr(cc->cpu, cpu)->iv_private;
+		r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size);
+		if (r)
+			err = r;
+	}
+
+	return err;
+}
+
+/* Set up per cpu cipher state */
+static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc,
+					     struct dm_target *ti,
+					     u8 *salt, unsigned saltsize)
+{
+	struct crypto_cipher *essiv_tfm;
+	int err;
+
+	/* Setup the essiv_tfm with the given salt */
+	essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(essiv_tfm)) {
+		ti->error = "Error allocating crypto tfm for ESSIV";
+		return essiv_tfm;
+	}
+
+	if (crypto_cipher_blocksize(essiv_tfm) !=
+	    crypto_ablkcipher_ivsize(any_tfm(cc))) {
+		ti->error = "Block size of ESSIV cipher does "
+			    "not match IV size of block cipher";
+		crypto_free_cipher(essiv_tfm);
+		return ERR_PTR(-EINVAL);
+	}
+
+	err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
+	if (err) {
+		ti->error = "Failed to set key for ESSIV cipher";
+		crypto_free_cipher(essiv_tfm);
+		return ERR_PTR(err);
+	}
+
+	return essiv_tfm;
+}
+
+static void crypt_iv_essiv_dtr(struct crypt_config *cc)
+{
+	int cpu;
+	struct crypt_cpu *cpu_cc;
+	struct crypto_cipher *essiv_tfm;
+	struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv;
+
+	crypto_free_hash(essiv->hash_tfm);
+	essiv->hash_tfm = NULL;
+
+	kzfree(essiv->salt);
+	essiv->salt = NULL;
+
+	for_each_possible_cpu(cpu) {
+		cpu_cc = per_cpu_ptr(cc->cpu, cpu);
+		essiv_tfm = cpu_cc->iv_private;
+
+		if (essiv_tfm)
+			crypto_free_cipher(essiv_tfm);
+
+		cpu_cc->iv_private = NULL;
+	}
+}
+
+static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
+			      const char *opts)
+{
+	struct crypto_cipher *essiv_tfm = NULL;
+	struct crypto_hash *hash_tfm = NULL;
+	u8 *salt = NULL;
+	int err, cpu;
+
+	if (!opts) {
+		ti->error = "Digest algorithm missing for ESSIV mode";
+		return -EINVAL;
+	}
+
+	/* Allocate hash algorithm */
+	hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(hash_tfm)) {
+		ti->error = "Error initializing ESSIV hash";
+		err = PTR_ERR(hash_tfm);
+		goto bad;
+	}
+
+	salt = kzalloc(crypto_hash_digestsize(hash_tfm), GFP_KERNEL);
+	if (!salt) {
+		ti->error = "Error kmallocing salt storage in ESSIV";
+		err = -ENOMEM;
+		goto bad;
+	}
+
+	cc->iv_gen_private.essiv.salt = salt;
+	cc->iv_gen_private.essiv.hash_tfm = hash_tfm;
+
+	for_each_possible_cpu(cpu) {
+		essiv_tfm = setup_essiv_cpu(cc, ti, salt,
+					crypto_hash_digestsize(hash_tfm));
+		if (IS_ERR(essiv_tfm)) {
+			crypt_iv_essiv_dtr(cc);
+			return PTR_ERR(essiv_tfm);
+		}
+		per_cpu_ptr(cc->cpu, cpu)->iv_private = essiv_tfm;
+	}
+
+	return 0;
+
+bad:
+	if (hash_tfm && !IS_ERR(hash_tfm))
+		crypto_free_hash(hash_tfm);
+	kfree(salt);
+	return err;
+}
+
+static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv,
+			      struct dm_crypt_request *dmreq)
+{
+	struct crypto_cipher *essiv_tfm = this_crypt_config(cc)->iv_private;
+
+	memset(iv, 0, cc->iv_size);
+	*(__le64 *)iv = cpu_to_le64(dmreq->iv_sector);
+	crypto_cipher_encrypt_one(essiv_tfm, iv, iv);
+
+	return 0;
+}
+
+static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
+			      const char *opts)
+{
+	unsigned bs = crypto_ablkcipher_blocksize(any_tfm(cc));
+	int log = ilog2(bs);
+
+	/* we need to calculate how far we must shift the sector count
+	 * to get the cipher block count, we use this shift in _gen */
+
+	if (1 << log != bs) {
+		ti->error = "cypher blocksize is not a power of 2";
+		return -EINVAL;
+	}
+
+	if (log > 9) {
+		ti->error = "cypher blocksize is > 512";
+		return -EINVAL;
+	}
+
+	cc->iv_gen_private.benbi.shift = 9 - log;
+
+	return 0;
+}
+
+static void crypt_iv_benbi_dtr(struct crypt_config *cc)
+{
+}
+
+static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv,
+			      struct dm_crypt_request *dmreq)
+{
+	__be64 val;
+
+	memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
+
+	val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1);
+	put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
+
+	return 0;
+}
+
+static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv,
+			     struct dm_crypt_request *dmreq)
+{
+	memset(iv, 0, cc->iv_size);
+
+	return 0;
+}
+
+static void crypt_iv_lmk_dtr(struct crypt_config *cc)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+
+	if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm))
+		crypto_free_shash(lmk->hash_tfm);
+	lmk->hash_tfm = NULL;
+
+	kzfree(lmk->seed);
+	lmk->seed = NULL;
+}
+
+static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti,
+			    const char *opts)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+
+	lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0);
+	if (IS_ERR(lmk->hash_tfm)) {
+		ti->error = "Error initializing LMK hash";
+		return PTR_ERR(lmk->hash_tfm);
+	}
+
+	/* No seed in LMK version 2 */
+	if (cc->key_parts == cc->tfms_count) {
+		lmk->seed = NULL;
+		return 0;
+	}
+
+	lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL);
+	if (!lmk->seed) {
+		crypt_iv_lmk_dtr(cc);
+		ti->error = "Error kmallocing seed storage in LMK";
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int crypt_iv_lmk_init(struct crypt_config *cc)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+	int subkey_size = cc->key_size / cc->key_parts;
+
+	/* LMK seed is on the position of LMK_KEYS + 1 key */
+	if (lmk->seed)
+		memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size),
+		       crypto_shash_digestsize(lmk->hash_tfm));
+
+	return 0;
+}
+
+static int crypt_iv_lmk_wipe(struct crypt_config *cc)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+
+	if (lmk->seed)
+		memset(lmk->seed, 0, LMK_SEED_SIZE);
+
+	return 0;
+}
+
+static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv,
+			    struct dm_crypt_request *dmreq,
+			    u8 *data)
+{
+	struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk;
+	struct {
+		struct shash_desc desc;
+		char ctx[crypto_shash_descsize(lmk->hash_tfm)];
+	} sdesc;
+	struct md5_state md5state;
+	u32 buf[4];
+	int i, r;
+
+	sdesc.desc.tfm = lmk->hash_tfm;
+	sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	r = crypto_shash_init(&sdesc.desc);
+	if (r)
+		return r;
+
+	if (lmk->seed) {
+		r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE);
+		if (r)
+			return r;
+	}
+
+	/* Sector is always 512B, block size 16, add data of blocks 1-31 */
+	r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31);
+	if (r)
+		return r;
+
+	/* Sector is cropped to 56 bits here */
+	buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF);
+	buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000);
+	buf[2] = cpu_to_le32(4024);
+	buf[3] = 0;
+	r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf));
+	if (r)
+		return r;
+
+	/* No MD5 padding here */
+	r = crypto_shash_export(&sdesc.desc, &md5state);
+	if (r)
+		return r;
+
+	for (i = 0; i < MD5_HASH_WORDS; i++)
+		__cpu_to_le32s(&md5state.hash[i]);
+	memcpy(iv, &md5state.hash, cc->iv_size);
+
+	return 0;
+}
+
+static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv,
+			    struct dm_crypt_request *dmreq)
+{
+	u8 *src;
+	int r = 0;
+
+	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
+		src = kmap_atomic(sg_page(&dmreq->sg_in));
+		r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset);
+		kunmap_atomic(src);
+	} else
+		memset(iv, 0, cc->iv_size);
+
+	return r;
+}
+
+static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv,
+			     struct dm_crypt_request *dmreq)
+{
+	u8 *dst;
+	int r;
+
+	if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
+		return 0;
+
+	dst = kmap_atomic(sg_page(&dmreq->sg_out));
+	r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset);
+
+	/* Tweak the first block of plaintext sector */
+	if (!r)
+		crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size);
+
+	kunmap_atomic(dst);
+	return r;
+}
+
+static struct crypt_iv_operations crypt_iv_plain_ops = {
+	.generator = crypt_iv_plain_gen
+};
+
+static struct crypt_iv_operations crypt_iv_plain64_ops = {
+	.generator = crypt_iv_plain64_gen
+};
+
+static struct crypt_iv_operations crypt_iv_essiv_ops = {
+	.ctr       = crypt_iv_essiv_ctr,
+	.dtr       = crypt_iv_essiv_dtr,
+	.init      = crypt_iv_essiv_init,
+	.wipe      = crypt_iv_essiv_wipe,
+	.generator = crypt_iv_essiv_gen
+};
+
+static struct crypt_iv_operations crypt_iv_benbi_ops = {
+	.ctr	   = crypt_iv_benbi_ctr,
+	.dtr	   = crypt_iv_benbi_dtr,
+	.generator = crypt_iv_benbi_gen
+};
+
+static struct crypt_iv_operations crypt_iv_null_ops = {
+	.generator = crypt_iv_null_gen
+};
+
+static struct crypt_iv_operations crypt_iv_lmk_ops = {
+	.ctr	   = crypt_iv_lmk_ctr,
+	.dtr	   = crypt_iv_lmk_dtr,
+	.init	   = crypt_iv_lmk_init,
+	.wipe	   = crypt_iv_lmk_wipe,
+	.generator = crypt_iv_lmk_gen,
+	.post	   = crypt_iv_lmk_post
+};
+
+static void crypt_convert_init(struct crypt_config *cc,
+			       struct convert_context *ctx,
+			       struct bio *bio_out, struct bio *bio_in,
+			       sector_t sector)
+{
+	ctx->bio_in = bio_in;
+	ctx->bio_out = bio_out;
+	ctx->offset_in = 0;
+	ctx->offset_out = 0;
+	ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
+	ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
+	ctx->sector = sector + cc->iv_offset;
+	init_completion(&ctx->restart);
+}
+
+static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc,
+					     struct ablkcipher_request *req)
+{
+	return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
+}
+
+static struct ablkcipher_request *req_of_dmreq(struct crypt_config *cc,
+					       struct dm_crypt_request *dmreq)
+{
+	return (struct ablkcipher_request *)((char *)dmreq - cc->dmreq_start);
+}
+
+static u8 *iv_of_dmreq(struct crypt_config *cc,
+		       struct dm_crypt_request *dmreq)
+{
+	return (u8 *)ALIGN((unsigned long)(dmreq + 1),
+		crypto_ablkcipher_alignmask(any_tfm(cc)) + 1);
+}
+
+static int crypt_convert_block(struct crypt_config *cc,
+			       struct convert_context *ctx,
+			       struct ablkcipher_request *req)
+{
+	struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
+	struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
+	struct dm_crypt_request *dmreq;
+	u8 *iv;
+	int r = 0;
+
+	dmreq = dmreq_of_req(cc, req);
+	iv = iv_of_dmreq(cc, dmreq);
+
+	dmreq->iv_sector = ctx->sector;
+	dmreq->ctx = ctx;
+	sg_init_table(&dmreq->sg_in, 1);
+	sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
+		    bv_in->bv_offset + ctx->offset_in);
+
+	sg_init_table(&dmreq->sg_out, 1);
+	sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
+		    bv_out->bv_offset + ctx->offset_out);
+
+	ctx->offset_in += 1 << SECTOR_SHIFT;
+	if (ctx->offset_in >= bv_in->bv_len) {
+		ctx->offset_in = 0;
+		ctx->idx_in++;
+	}
+
+	ctx->offset_out += 1 << SECTOR_SHIFT;
+	if (ctx->offset_out >= bv_out->bv_len) {
+		ctx->offset_out = 0;
+		ctx->idx_out++;
+	}
+
+	if (cc->iv_gen_ops) {
+		r = cc->iv_gen_ops->generator(cc, iv, dmreq);
+		if (r < 0)
+			return r;
+	}
+
+	ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
+				     1 << SECTOR_SHIFT, iv);
+
+	if (bio_data_dir(ctx->bio_in) == WRITE)
+		r = crypto_ablkcipher_encrypt(req);
+	else
+		r = crypto_ablkcipher_decrypt(req);
+
+	if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
+		r = cc->iv_gen_ops->post(cc, iv, dmreq);
+
+	return r;
+}
+
+static void kcryptd_async_done(struct crypto_async_request *async_req,
+			       int error);
+
+static void crypt_alloc_req(struct crypt_config *cc,
+			    struct convert_context *ctx)
+{
+	struct crypt_cpu *this_cc = this_crypt_config(cc);
+	unsigned key_index = ctx->sector & (cc->tfms_count - 1);
+
+	if (!this_cc->req)
+		this_cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
+
+	ablkcipher_request_set_tfm(this_cc->req, this_cc->tfms[key_index]);
+	ablkcipher_request_set_callback(this_cc->req,
+	    CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+	    kcryptd_async_done, dmreq_of_req(cc, this_cc->req));
+}
+
+/*
+ * Encrypt / decrypt data from one bio to another one (can be the same one)
+ */
+static int crypt_convert(struct crypt_config *cc,
+			 struct convert_context *ctx)
+{
+	struct crypt_cpu *this_cc = this_crypt_config(cc);
+	int r;
+
+	atomic_set(&ctx->pending, 1);
+
+	while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
+	      ctx->idx_out < ctx->bio_out->bi_vcnt) {
+
+		crypt_alloc_req(cc, ctx);
+
+		atomic_inc(&ctx->pending);
+
+		r = crypt_convert_block(cc, ctx, this_cc->req);
+
+		switch (r) {
+		/* async */
+		case -EINPROGRESS:
+		case -EBUSY:
+			wait_for_completion(&ctx->restart);
+			INIT_COMPLETION(ctx->restart);
+			this_cc->req = NULL;
+			ctx->sector++;
+			continue;
+
+		/* sync */
+		case 0:
+			atomic_dec(&ctx->pending);
+			ctx->sector++;
+			cond_resched();
+			continue;
+
+		/* error */
+		default:
+			atomic_dec(&ctx->pending);
+			return r;
+		}
+	}
+
+	return 0;
+}
+
+static void dm_crypt_bio_destructor(struct bio *bio)
+{
+	struct dm_crypt_io *io = bio->bi_private;
+	struct crypt_config *cc = io->target->private;
+
+	bio_free(bio, cc->bs);
+}
+
+/*
+ * Generate a new unfragmented bio with the given size
+ * This should never violate the device limitations
+ * May return a smaller bio when running out of pages, indicated by
+ * *out_of_pages set to 1.
+ */
+static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size,
+				      unsigned *out_of_pages)
+{
+	struct crypt_config *cc = io->target->private;
+	struct bio *clone;
+	unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
+	unsigned i, len;
+	struct page *page;
+
+	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
+	if (!clone)
+		return NULL;
+
+	clone_init(io, clone);
+	*out_of_pages = 0;
+
+	for (i = 0; i < nr_iovecs; i++) {
+		page = mempool_alloc(cc->page_pool, gfp_mask);
+		if (!page) {
+			*out_of_pages = 1;
+			break;
+		}
+
+		/*
+		 * If additional pages cannot be allocated without waiting,
+		 * return a partially-allocated bio.  The caller will then try
+		 * to allocate more bios while submitting this partial bio.
+		 */
+		gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
+
+		len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
+
+		if (!bio_add_page(clone, page, len, 0)) {
+			mempool_free(page, cc->page_pool);
+			break;
+		}
+
+		size -= len;
+	}
+
+	if (!clone->bi_size) {
+		bio_put(clone);
+		return NULL;
+	}
+
+	return clone;
+}
+
+static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
+{
+	unsigned int i;
+	struct bio_vec *bv;
+
+	for (i = 0; i < clone->bi_vcnt; i++) {
+		bv = bio_iovec_idx(clone, i);
+		BUG_ON(!bv->bv_page);
+		mempool_free(bv->bv_page, cc->page_pool);
+		bv->bv_page = NULL;
+	}
+}
+
+static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
+					  struct bio *bio, sector_t sector)
+{
+	struct crypt_config *cc = ti->private;
+	struct dm_crypt_io *io;
+
+	io = mempool_alloc(cc->io_pool, GFP_NOIO);
+	io->target = ti;
+	io->base_bio = bio;
+	io->sector = sector;
+	io->error = 0;
+	io->base_io = NULL;
+	atomic_set(&io->pending, 0);
+
+	return io;
+}
+
+static void crypt_inc_pending(struct dm_crypt_io *io)
+{
+	atomic_inc(&io->pending);
+}
+
+/*
+ * One of the bios was finished. Check for completion of
+ * the whole request and correctly clean up the buffer.
+ * If base_io is set, wait for the last fragment to complete.
+ */
+static void crypt_dec_pending(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->target->private;
+	struct bio *base_bio = io->base_bio;
+	struct dm_crypt_io *base_io = io->base_io;
+	int error = io->error;
+
+	if (!atomic_dec_and_test(&io->pending))
+		return;
+
+	mempool_free(io, cc->io_pool);
+
+	if (likely(!base_io))
+		bio_endio(base_bio, error);
+	else {
+		if (error && !base_io->error)
+			base_io->error = error;
+		crypt_dec_pending(base_io);
+	}
+}
+
+/*
+ * kcryptd/kcryptd_io:
+ *
+ * Needed because it would be very unwise to do decryption in an
+ * interrupt context.
+ *
+ * kcryptd performs the actual encryption or decryption.
+ *
+ * kcryptd_io performs the IO submission.
+ *
+ * They must be separated as otherwise the final stages could be
+ * starved by new requests which can block in the first stages due
+ * to memory allocation.
+ *
+ * The work is done per CPU global for all dm-crypt instances.
+ * They should not depend on each other and do not block.
+ */
+static void crypt_endio(struct bio *clone, int error)
+{
+	struct dm_crypt_io *io = clone->bi_private;
+	struct crypt_config *cc = io->target->private;
+	unsigned rw = bio_data_dir(clone);
+
+	if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
+		error = -EIO;
+
+	/*
+	 * free the processed pages
+	 */
+	if (rw == WRITE)
+		crypt_free_buffer_pages(cc, clone);
+
+	bio_put(clone);
+
+	if (rw == READ && !error) {
+		kcryptd_queue_crypt(io);
+		return;
+	}
+
+	if (unlikely(error))
+		io->error = error;
+
+	crypt_dec_pending(io);
+}
+
+static void clone_init(struct dm_crypt_io *io, struct bio *clone)
+{
+	struct crypt_config *cc = io->target->private;
+
+	clone->bi_private = io;
+	clone->bi_end_io  = crypt_endio;
+	clone->bi_bdev    = cc->dev->bdev;
+	clone->bi_rw      = io->base_bio->bi_rw;
+	clone->bi_destructor = dm_crypt_bio_destructor;
+}
+
+static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
+{
+	struct crypt_config *cc = io->target->private;
+	struct bio *base_bio = io->base_bio;
+	struct bio *clone;
+
+	/*
+	 * The block layer might modify the bvec array, so always
+	 * copy the required bvecs because we need the original
+	 * one in order to decrypt the whole bio data *afterwards*.
+	 */
+	clone = bio_alloc_bioset(gfp, bio_segments(base_bio), cc->bs);
+	if (!clone)
+		return 1;
+
+	crypt_inc_pending(io);
+
+	clone_init(io, clone);
+	clone->bi_idx = 0;
+	clone->bi_vcnt = bio_segments(base_bio);
+	clone->bi_size = base_bio->bi_size;
+	clone->bi_sector = cc->start + io->sector;
+	memcpy(clone->bi_io_vec, bio_iovec(base_bio),
+	       sizeof(struct bio_vec) * clone->bi_vcnt);
+
+	generic_make_request(clone);
+	return 0;
+}
+
+static void kcryptd_io_write(struct dm_crypt_io *io)
+{
+	struct bio *clone = io->ctx.bio_out;
+	generic_make_request(clone);
+}
+
+static void kcryptd_io(struct work_struct *work)
+{
+	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
+
+	if (bio_data_dir(io->base_bio) == READ) {
+		crypt_inc_pending(io);
+		if (kcryptd_io_read(io, GFP_NOIO))
+			io->error = -ENOMEM;
+		crypt_dec_pending(io);
+	} else
+		kcryptd_io_write(io);
+}
+
+static void kcryptd_queue_io(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->target->private;
+
+	INIT_WORK(&io->work, kcryptd_io);
+	queue_work(cc->io_queue, &io->work);
+}
+
+static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
+{
+	struct bio *clone = io->ctx.bio_out;
+	struct crypt_config *cc = io->target->private;
+
+	if (unlikely(io->error < 0)) {
+		crypt_free_buffer_pages(cc, clone);
+		bio_put(clone);
+		crypt_dec_pending(io);
+		return;
+	}
+
+	/* crypt_convert should have filled the clone bio */
+	BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
+
+	clone->bi_sector = cc->start + io->sector;
+
+	if (async)
+		kcryptd_queue_io(io);
+	else
+		generic_make_request(clone);
+}
+
+static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->target->private;
+	struct bio *clone;
+	struct dm_crypt_io *new_io;
+	int crypt_finished;
+	unsigned out_of_pages = 0;
+	unsigned remaining = io->base_bio->bi_size;
+	sector_t sector = io->sector;
+	int r;
+
+	/*
+	 * Prevent io from disappearing until this function completes.
+	 */
+	crypt_inc_pending(io);
+	crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector);
+
+	/*
+	 * The allocated buffers can be smaller than the whole bio,
+	 * so repeat the whole process until all the data can be handled.
+	 */
+	while (remaining) {
+		clone = crypt_alloc_buffer(io, remaining, &out_of_pages);
+		if (unlikely(!clone)) {
+			io->error = -ENOMEM;
+			break;
+		}
+
+		io->ctx.bio_out = clone;
+		io->ctx.idx_out = 0;
+
+		remaining -= clone->bi_size;
+		sector += bio_sectors(clone);
+
+		crypt_inc_pending(io);
+
+		r = crypt_convert(cc, &io->ctx);
+		if (r < 0)
+			io->error = -EIO;
+
+		crypt_finished = atomic_dec_and_test(&io->ctx.pending);
+
+		/* Encryption was already finished, submit io now */
+		if (crypt_finished) {
+			kcryptd_crypt_write_io_submit(io, 0);
+
+			/*
+			 * If there was an error, do not try next fragments.
+			 * For async, error is processed in async handler.
+			 */
+			if (unlikely(r < 0))
+				break;
+
+			io->sector = sector;
+		}
+
+		/*
+		 * Out of memory -> run queues
+		 * But don't wait if split was due to the io size restriction
+		 */
+		if (unlikely(out_of_pages))
+			congestion_wait(BLK_RW_ASYNC, HZ/100);
+
+		/*
+		 * With async crypto it is unsafe to share the crypto context
+		 * between fragments, so switch to a new dm_crypt_io structure.
+		 */
+		if (unlikely(!crypt_finished && remaining)) {
+			new_io = crypt_io_alloc(io->target, io->base_bio,
+						sector);
+			crypt_inc_pending(new_io);
+			crypt_convert_init(cc, &new_io->ctx, NULL,
+					   io->base_bio, sector);
+			new_io->ctx.idx_in = io->ctx.idx_in;
+			new_io->ctx.offset_in = io->ctx.offset_in;
+
+			/*
+			 * Fragments after the first use the base_io
+			 * pending count.
+			 */
+			if (!io->base_io)
+				new_io->base_io = io;
+			else {
+				new_io->base_io = io->base_io;
+				crypt_inc_pending(io->base_io);
+				crypt_dec_pending(io);
+			}
+
+			io = new_io;
+		}
+	}
+
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_crypt_read_done(struct dm_crypt_io *io)
+{
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->target->private;
+	int r = 0;
+
+	crypt_inc_pending(io);
+
+	crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
+			   io->sector);
+
+	r = crypt_convert(cc, &io->ctx);
+	if (r < 0)
+		io->error = -EIO;
+
+	if (atomic_dec_and_test(&io->ctx.pending))
+		kcryptd_crypt_read_done(io);
+
+	crypt_dec_pending(io);
+}
+
+static void kcryptd_async_done(struct crypto_async_request *async_req,
+			       int error)
+{
+	struct dm_crypt_request *dmreq = async_req->data;
+	struct convert_context *ctx = dmreq->ctx;
+	struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
+	struct crypt_config *cc = io->target->private;
+
+	if (error == -EINPROGRESS)
+		return;
+
+	if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
+		error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
+
+	if (error < 0)
+		io->error = -EIO;
+
+	mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool);
+
+	if (!atomic_dec_and_test(&ctx->pending))
+		goto done;
+
+	if (bio_data_dir(io->base_bio) == READ)
+		kcryptd_crypt_read_done(io);
+	else
+		kcryptd_crypt_write_io_submit(io, 1);
+done:
+	if (!completion_done(&ctx->restart))
+		complete(&ctx->restart);
+}
+
+static void kcryptd_crypt(struct work_struct *work)
+{
+	struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
+
+	if (bio_data_dir(io->base_bio) == READ)
+		kcryptd_crypt_read_convert(io);
+	else
+		kcryptd_crypt_write_convert(io);
+}
+
+static void kcryptd_queue_crypt(struct dm_crypt_io *io)
+{
+	struct crypt_config *cc = io->target->private;
+
+	INIT_WORK(&io->work, kcryptd_crypt);
+	queue_work(cc->crypt_queue, &io->work);
+}
+
+/*
+ * Decode key from its hex representation
+ */
+static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
+{
+	char buffer[3];
+	char *endp;
+	unsigned int i;
+
+	buffer[2] = '\0';
+
+	for (i = 0; i < size; i++) {
+		buffer[0] = *hex++;
+		buffer[1] = *hex++;
+
+		key[i] = (u8)simple_strtoul(buffer, &endp, 16);
+
+		if (endp != &buffer[2])
+			return -EINVAL;
+	}
+
+	if (*hex != '\0')
+		return -EINVAL;
+
+	return 0;
+}
+
+static void crypt_free_tfms(struct crypt_config *cc, int cpu)
+{
+	struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
+	unsigned i;
+
+	for (i = 0; i < cc->tfms_count; i++)
+		if (cpu_cc->tfms[i] && !IS_ERR(cpu_cc->tfms[i])) {
+			crypto_free_ablkcipher(cpu_cc->tfms[i]);
+			cpu_cc->tfms[i] = NULL;
+		}
+}
+
+static int crypt_alloc_tfms(struct crypt_config *cc, int cpu, char *ciphermode)
+{
+	struct crypt_cpu *cpu_cc = per_cpu_ptr(cc->cpu, cpu);
+	unsigned i;
+	int err;
+
+	for (i = 0; i < cc->tfms_count; i++) {
+		cpu_cc->tfms[i] = crypto_alloc_ablkcipher(ciphermode, 0, 0);
+		if (IS_ERR(cpu_cc->tfms[i])) {
+			err = PTR_ERR(cpu_cc->tfms[i]);
+			crypt_free_tfms(cc, cpu);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int crypt_setkey_allcpus(struct crypt_config *cc)
+{
+	unsigned subkey_size = cc->key_size >> ilog2(cc->tfms_count);
+	int cpu, err = 0, i, r;
+
+	for_each_possible_cpu(cpu) {
+		for (i = 0; i < cc->tfms_count; i++) {
+			r = crypto_ablkcipher_setkey(per_cpu_ptr(cc->cpu, cpu)->tfms[i],
+						     cc->key + (i * subkey_size), subkey_size);
+			if (r)
+				err = r;
+		}
+	}
+
+	return err;
+}
+
+static int crypt_set_key(struct crypt_config *cc, char *key)
+{
+	int r = -EINVAL;
+	int key_string_len = strlen(key);
+
+	/* The key size may not be changed. */
+	if (cc->key_size != (key_string_len >> 1))
+		goto out;
+
+	/* Hyphen (which gives a key_size of zero) means there is no key. */
+	if (!cc->key_size && strcmp(key, "-"))
+		goto out;
+
+	if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0)
+		goto out;
+
+	set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
+
+	r = crypt_setkey_allcpus(cc);
+
+out:
+	/* Hex key string not needed after here, so wipe it. */
+	memset(key, '0', key_string_len);
+
+	return r;
+}
+
+static int crypt_wipe_key(struct crypt_config *cc)
+{
+	clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
+	memset(&cc->key, 0, cc->key_size * sizeof(u8));
+
+	return crypt_setkey_allcpus(cc);
+}
+
+static void crypt_dtr(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+	struct crypt_cpu *cpu_cc;
+	int cpu;
+
+	ti->private = NULL;
+
+	if (!cc)
+		return;
+
+	if (cc->io_queue)
+		destroy_workqueue(cc->io_queue);
+	if (cc->crypt_queue)
+		destroy_workqueue(cc->crypt_queue);
+
+	if (cc->cpu)
+		for_each_possible_cpu(cpu) {
+			cpu_cc = per_cpu_ptr(cc->cpu, cpu);
+			if (cpu_cc->req)
+				mempool_free(cpu_cc->req, cc->req_pool);
+			crypt_free_tfms(cc, cpu);
+		}
+
+	if (cc->bs)
+		bioset_free(cc->bs);
+
+	if (cc->page_pool)
+		mempool_destroy(cc->page_pool);
+	if (cc->req_pool)
+		mempool_destroy(cc->req_pool);
+	if (cc->io_pool)
+		mempool_destroy(cc->io_pool);
+
+	if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+		cc->iv_gen_ops->dtr(cc);
+
+	if (cc->dev)
+		dm_put_device(ti, cc->dev);
+
+	if (cc->cpu)
+		free_percpu(cc->cpu);
+
+	kzfree(cc->cipher);
+	kzfree(cc->cipher_string);
+
+	/* Must zero key material before freeing */
+	kzfree(cc);
+}
+
+static int crypt_ctr_cipher(struct dm_target *ti,
+			    char *cipher_in, char *key)
+{
+	struct crypt_config *cc = ti->private;
+	char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount;
+	char *cipher_api = NULL;
+	int cpu, ret = -EINVAL;
+	char dummy;
+
+	/* Convert to crypto api definition? */
+	if (strchr(cipher_in, '(')) {
+		ti->error = "Bad cipher specification";
+		return -EINVAL;
+	}
+
+	cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
+	if (!cc->cipher_string)
+		goto bad_mem;
+
+	/*
+	 * Legacy dm-crypt cipher specification
+	 * cipher[:keycount]-mode-iv:ivopts
+	 */
+	tmp = cipher_in;
+	keycount = strsep(&tmp, "-");
+	cipher = strsep(&keycount, ":");
+
+	if (!keycount)
+		cc->tfms_count = 1;
+	else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 ||
+		 !is_power_of_2(cc->tfms_count)) {
+		ti->error = "Bad cipher key count specification";
+		return -EINVAL;
+	}
+	cc->key_parts = cc->tfms_count;
+
+	cc->cipher = kstrdup(cipher, GFP_KERNEL);
+	if (!cc->cipher)
+		goto bad_mem;
+
+	chainmode = strsep(&tmp, "-");
+	ivopts = strsep(&tmp, "-");
+	ivmode = strsep(&ivopts, ":");
+
+	if (tmp)
+		DMWARN("Ignoring unexpected additional cipher options");
+
+	cc->cpu = __alloc_percpu(sizeof(*(cc->cpu)) +
+				 cc->tfms_count * sizeof(*(cc->cpu->tfms)),
+				 __alignof__(struct crypt_cpu));
+	if (!cc->cpu) {
+		ti->error = "Cannot allocate per cpu state";
+		goto bad_mem;
+	}
+
+	/*
+	 * For compatibility with the original dm-crypt mapping format, if
+	 * only the cipher name is supplied, use cbc-plain.
+	 */
+	if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) {
+		chainmode = "cbc";
+		ivmode = "plain";
+	}
+
+	if (strcmp(chainmode, "ecb") && !ivmode) {
+		ti->error = "IV mechanism required";
+		return -EINVAL;
+	}
+
+	cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL);
+	if (!cipher_api)
+		goto bad_mem;
+
+	ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME,
+		       "%s(%s)", chainmode, cipher);
+	if (ret < 0) {
+		kfree(cipher_api);
+		goto bad_mem;
+	}
+
+	/* Allocate cipher */
+	for_each_possible_cpu(cpu) {
+		ret = crypt_alloc_tfms(cc, cpu, cipher_api);
+		if (ret < 0) {
+			ti->error = "Error allocating crypto tfm";
+			goto bad;
+		}
+	}
+
+	/* Initialize and set key */
+	ret = crypt_set_key(cc, key);
+	if (ret < 0) {
+		ti->error = "Error decoding and setting key";
+		goto bad;
+	}
+
+	/* Initialize IV */
+	cc->iv_size = crypto_ablkcipher_ivsize(any_tfm(cc));
+	if (cc->iv_size)
+		/* at least a 64 bit sector number should fit in our buffer */
+		cc->iv_size = max(cc->iv_size,
+				  (unsigned int)(sizeof(u64) / sizeof(u8)));
+	else if (ivmode) {
+		DMWARN("Selected cipher does not support IVs");
+		ivmode = NULL;
+	}
+
+	/* Choose ivmode, see comments at iv code. */
+	if (ivmode == NULL)
+		cc->iv_gen_ops = NULL;
+	else if (strcmp(ivmode, "plain") == 0)
+		cc->iv_gen_ops = &crypt_iv_plain_ops;
+	else if (strcmp(ivmode, "plain64") == 0)
+		cc->iv_gen_ops = &crypt_iv_plain64_ops;
+	else if (strcmp(ivmode, "essiv") == 0)
+		cc->iv_gen_ops = &crypt_iv_essiv_ops;
+	else if (strcmp(ivmode, "benbi") == 0)
+		cc->iv_gen_ops = &crypt_iv_benbi_ops;
+	else if (strcmp(ivmode, "null") == 0)
+		cc->iv_gen_ops = &crypt_iv_null_ops;
+	else if (strcmp(ivmode, "lmk") == 0) {
+		cc->iv_gen_ops = &crypt_iv_lmk_ops;
+		/* Version 2 and 3 is recognised according
+		 * to length of provided multi-key string.
+		 * If present (version 3), last key is used as IV seed.
+		 */
+		if (cc->key_size % cc->key_parts)
+			cc->key_parts++;
+	} else {
+		ret = -EINVAL;
+		ti->error = "Invalid IV mode";
+		goto bad;
+	}
+
+	/* Allocate IV */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) {
+		ret = cc->iv_gen_ops->ctr(cc, ti, ivopts);
+		if (ret < 0) {
+			ti->error = "Error creating IV";
+			goto bad;
+		}
+	}
+
+	/* Initialize IV (set keys for ESSIV etc) */
+	if (cc->iv_gen_ops && cc->iv_gen_ops->init) {
+		ret = cc->iv_gen_ops->init(cc);
+		if (ret < 0) {
+			ti->error = "Error initialising IV";
+			goto bad;
+		}
+	}
+
+	ret = 0;
+bad:
+	kfree(cipher_api);
+	return ret;
+
+bad_mem:
+	ti->error = "Cannot allocate cipher strings";
+	return -ENOMEM;
+}
+
+/*
+ * Construct an encryption mapping:
+ * <cipher> <key> <iv_offset> <dev_path> <start>
+ */
+static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct crypt_config *cc;
+	unsigned int key_size, opt_params;
+	unsigned long long tmpll;
+	int ret;
+	size_t iv_size_padding;
+	struct dm_arg_set as;
+	const char *opt_string;
+	char dummy;
+
+	static struct dm_arg _args[] = {
+		{0, 1, "Invalid number of feature args"},
+	};
+
+	if (argc < 5) {
+		ti->error = "Not enough arguments";
+		return -EINVAL;
+	}
+
+	key_size = strlen(argv[1]) >> 1;
+
+	cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
+	if (!cc) {
+		ti->error = "Cannot allocate encryption context";
+		return -ENOMEM;
+	}
+	cc->key_size = key_size;
+
+	ti->private = cc;
+	ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
+	if (ret < 0)
+		goto bad;
+
+	ret = -ENOMEM;
+	cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
+	if (!cc->io_pool) {
+		ti->error = "Cannot allocate crypt io mempool";
+		goto bad;
+	}
+
+	cc->dmreq_start = sizeof(struct ablkcipher_request);
+	cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
+	cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
+
+	if (crypto_ablkcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) {
+		/* Allocate the padding exactly */
+		iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
+				& crypto_ablkcipher_alignmask(any_tfm(cc));
+	} else {
+		/*
+		 * If the cipher requires greater alignment than kmalloc
+		 * alignment, we don't know the exact position of the
+		 * initialization vector. We must assume worst case.
+		 */
+		iv_size_padding = crypto_ablkcipher_alignmask(any_tfm(cc));
+	}
+
+	cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
+			sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size);
+	if (!cc->req_pool) {
+		ti->error = "Cannot allocate crypt request mempool";
+		goto bad;
+	}
+
+	cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
+	if (!cc->page_pool) {
+		ti->error = "Cannot allocate page mempool";
+		goto bad;
+	}
+
+	cc->bs = bioset_create(MIN_IOS, 0);
+	if (!cc->bs) {
+		ti->error = "Cannot allocate crypt bioset";
+		goto bad;
+	}
+
+	ret = -EINVAL;
+	if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) {
+		ti->error = "Invalid iv_offset sector";
+		goto bad;
+	}
+	cc->iv_offset = tmpll;
+
+	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev)) {
+		ti->error = "Device lookup failed";
+		goto bad;
+	}
+
+	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
+		ti->error = "Invalid device sector";
+		goto bad;
+	}
+	cc->start = tmpll;
+
+	argv += 5;
+	argc -= 5;
+
+	/* Optional parameters */
+	if (argc) {
+		as.argc = argc;
+		as.argv = argv;
+
+		ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
+		if (ret)
+			goto bad;
+
+		opt_string = dm_shift_arg(&as);
+
+		if (opt_params == 1 && opt_string &&
+		    !strcasecmp(opt_string, "allow_discards"))
+			ti->num_discard_requests = 1;
+		else if (opt_params) {
+			ret = -EINVAL;
+			ti->error = "Invalid feature arguments";
+			goto bad;
+		}
+	}
+
+	ret = -ENOMEM;
+	cc->io_queue = alloc_workqueue("kcryptd_io",
+				       WQ_NON_REENTRANT|
+				       WQ_MEM_RECLAIM,
+				       1);
+	if (!cc->io_queue) {
+		ti->error = "Couldn't create kcryptd io queue";
+		goto bad;
+	}
+
+	cc->crypt_queue = alloc_workqueue("kcryptd",
+					  WQ_NON_REENTRANT|
+					  WQ_CPU_INTENSIVE|
+					  WQ_MEM_RECLAIM,
+					  1);
+	if (!cc->crypt_queue) {
+		ti->error = "Couldn't create kcryptd queue";
+		goto bad;
+	}
+
+	ti->num_flush_requests = 1;
+	ti->discard_zeroes_data_unsupported = 1;
+
+	return 0;
+
+bad:
+	crypt_dtr(ti);
+	return ret;
+}
+
+static int crypt_map(struct dm_target *ti, struct bio *bio,
+		     union map_info *map_context)
+{
+	struct dm_crypt_io *io;
+	struct crypt_config *cc;
+
+	/*
+	 * If bio is REQ_FLUSH or REQ_DISCARD, just bypass crypt queues.
+	 * - for REQ_FLUSH device-mapper core ensures that no IO is in-flight
+	 * - for REQ_DISCARD caller must use flush if IO ordering matters
+	 */
+	if (unlikely(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD))) {
+		cc = ti->private;
+		bio->bi_bdev = cc->dev->bdev;
+		if (bio_sectors(bio))
+			bio->bi_sector = cc->start + dm_target_offset(ti, bio->bi_sector);
+		return DM_MAPIO_REMAPPED;
+	}
+
+	io = crypt_io_alloc(ti, bio, dm_target_offset(ti, bio->bi_sector));
+
+	if (bio_data_dir(io->base_bio) == READ) {
+		if (kcryptd_io_read(io, GFP_NOWAIT))
+			kcryptd_queue_io(io);
+	} else
+		kcryptd_queue_crypt(io);
+
+	return DM_MAPIO_SUBMITTED;
+}
+
+static void crypt_status(struct dm_target *ti, status_type_t type,
+			 char *result, unsigned int maxlen)
+{
+	struct crypt_config *cc = ti->private;
+	unsigned i, sz = 0;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		result[0] = '\0';
+		break;
+
+	case STATUSTYPE_TABLE:
+		DMEMIT("%s ", cc->cipher_string);
+
+		if (cc->key_size > 0)
+			for (i = 0; i < cc->key_size; i++)
+				DMEMIT("%02x", cc->key[i]);
+		else
+			DMEMIT("-");
+
+		DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
+				cc->dev->name, (unsigned long long)cc->start);
+
+		if (ti->num_discard_requests)
+			DMEMIT(" 1 allow_discards");
+
+		break;
+	}
+}
+
+static void crypt_postsuspend(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	set_bit(DM_CRYPT_SUSPENDED, &cc->flags);
+}
+
+static int crypt_preresume(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) {
+		DMERR("aborting resume - crypt key is not set.");
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static void crypt_resume(struct dm_target *ti)
+{
+	struct crypt_config *cc = ti->private;
+
+	clear_bit(DM_CRYPT_SUSPENDED, &cc->flags);
+}
+
+/* Message interface
+ *	key set <key>
+ *	key wipe
+ */
+static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+	struct crypt_config *cc = ti->private;
+	int ret = -EINVAL;
+
+	if (argc < 2)
+		goto error;
+
+	if (!strcasecmp(argv[0], "key")) {
+		if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
+			DMWARN("not suspended during key manipulation.");
+			return -EINVAL;
+		}
+		if (argc == 3 && !strcasecmp(argv[1], "set")) {
+			ret = crypt_set_key(cc, argv[2]);
+			if (ret)
+				return ret;
+			if (cc->iv_gen_ops && cc->iv_gen_ops->init)
+				ret = cc->iv_gen_ops->init(cc);
+			return ret;
+		}
+		if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
+			if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
+				ret = cc->iv_gen_ops->wipe(cc);
+				if (ret)
+					return ret;
+			}
+			return crypt_wipe_key(cc);
+		}
+	}
+
+error:
+	DMWARN("unrecognised message received.");
+	return -EINVAL;
+}
+
+static int crypt_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
+		       struct bio_vec *biovec, int max_size)
+{
+	struct crypt_config *cc = ti->private;
+	struct request_queue *q = bdev_get_queue(cc->dev->bdev);
+
+	if (!q->merge_bvec_fn)
+		return max_size;
+
+	bvm->bi_bdev = cc->dev->bdev;
+	bvm->bi_sector = cc->start + dm_target_offset(ti, bvm->bi_sector);
+
+	return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
+static int crypt_iterate_devices(struct dm_target *ti,
+				 iterate_devices_callout_fn fn, void *data)
+{
+	struct crypt_config *cc = ti->private;
+
+	return fn(ti, cc->dev, cc->start, ti->len, data);
+}
+
+static struct target_type crypt_target = {
+	.name   = "crypt",
+	.version = {1, 11, 0},
+	.module = THIS_MODULE,
+	.ctr    = crypt_ctr,
+	.dtr    = crypt_dtr,
+	.map    = crypt_map,
+	.status = crypt_status,
+	.postsuspend = crypt_postsuspend,
+	.preresume = crypt_preresume,
+	.resume = crypt_resume,
+	.message = crypt_message,
+	.merge  = crypt_merge,
+	.iterate_devices = crypt_iterate_devices,
+};
+
+static int __init dm_crypt_init(void)
+{
+	int r;
+
+	_crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
+	if (!_crypt_io_pool)
+		return -ENOMEM;
+
+	r = dm_register_target(&crypt_target);
+	if (r < 0) {
+		DMERR("register failed %d", r);
+		kmem_cache_destroy(_crypt_io_pool);
+	}
+
+	return r;
+}
+
+static void __exit dm_crypt_exit(void)
+{
+	dm_unregister_target(&crypt_target);
+	kmem_cache_destroy(_crypt_io_pool);
+}
+
+module_init(dm_crypt_init);
+module_exit(dm_crypt_exit);
+
+MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
+MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
+MODULE_LICENSE("GPL");