/*
   * Software async crypto daemon.
   *
   * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation; either version 2 of the License, or (at your option)
   * any later version.
   *
   */
  
  #include <crypto/algapi.h>

  #include <crypto/internal/hash.h>

  #include <crypto/cryptd.h>

  #include <crypto/crypto_wq.h>

  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/kernel.h>

  #include <linux/list.h>
  #include <linux/module.h>

  #include <linux/scatterlist.h>
  #include <linux/sched.h>
  #include <linux/slab.h>

  #define CRYPTD_MAX_CPU_QLEN 100

  struct cryptd_cpu_queue {

  	struct crypto_queue queue;

  	struct work_struct work;
  };
  
  struct cryptd_queue {

  	struct cryptd_cpu_queue __percpu *cpu_queue;

  };
  
  struct cryptd_instance_ctx {
  	struct crypto_spawn spawn;

  	struct cryptd_queue *queue;

  };

  struct hashd_instance_ctx {
  	struct crypto_shash_spawn spawn;
  	struct cryptd_queue *queue;
  };

  struct cryptd_blkcipher_ctx {
  	struct crypto_blkcipher *child;
  };
  
  struct cryptd_blkcipher_request_ctx {
  	crypto_completion_t complete;
  };

  struct cryptd_hash_ctx {

  	struct crypto_shash *child;

  };
  
  struct cryptd_hash_request_ctx {
  	crypto_completion_t complete;

  	struct shash_desc desc;

  };

  static void cryptd_queue_worker(struct work_struct *work);
  
  static int cryptd_init_queue(struct cryptd_queue *queue,
  			     unsigned int max_cpu_qlen)
  {
  	int cpu;
  	struct cryptd_cpu_queue *cpu_queue;
  
  	queue->cpu_queue = alloc_percpu(struct cryptd_cpu_queue);
  	if (!queue->cpu_queue)
  		return -ENOMEM;
  	for_each_possible_cpu(cpu) {
  		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
  		crypto_init_queue(&cpu_queue->queue, max_cpu_qlen);
  		INIT_WORK(&cpu_queue->work, cryptd_queue_worker);
  	}
  	return 0;
  }
  
  static void cryptd_fini_queue(struct cryptd_queue *queue)
  {
  	int cpu;
  	struct cryptd_cpu_queue *cpu_queue;
  
  	for_each_possible_cpu(cpu) {
  		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
  		BUG_ON(cpu_queue->queue.qlen);
  	}
  	free_percpu(queue->cpu_queue);
  }
  
  static int cryptd_enqueue_request(struct cryptd_queue *queue,
  				  struct crypto_async_request *request)
  {
  	int cpu, err;
  	struct cryptd_cpu_queue *cpu_queue;
  
  	cpu = get_cpu();

  	cpu_queue = this_cpu_ptr(queue->cpu_queue);

  	err = crypto_enqueue_request(&cpu_queue->queue, request);
  	queue_work_on(cpu, kcrypto_wq, &cpu_queue->work);
  	put_cpu();
  
  	return err;
  }
  
  /* Called in workqueue context, do one real cryption work (via
   * req->complete) and reschedule itself if there are more work to
   * do. */
  static void cryptd_queue_worker(struct work_struct *work)
  {
  	struct cryptd_cpu_queue *cpu_queue;
  	struct crypto_async_request *req, *backlog;
  
  	cpu_queue = container_of(work, struct cryptd_cpu_queue, work);
  	/* Only handle one request at a time to avoid hogging crypto
  	 * workqueue. preempt_disable/enable is used to prevent
  	 * being preempted by cryptd_enqueue_request() */
  	preempt_disable();
  	backlog = crypto_get_backlog(&cpu_queue->queue);
  	req = crypto_dequeue_request(&cpu_queue->queue);
  	preempt_enable();
  
  	if (!req)
  		return;
  
  	if (backlog)
  		backlog->complete(backlog, -EINPROGRESS);
  	req->complete(req, 0);
  
  	if (cpu_queue->queue.qlen)
  		queue_work(kcrypto_wq, &cpu_queue->work);
  }
  
  static inline struct cryptd_queue *cryptd_get_queue(struct crypto_tfm *tfm)

  {
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);

  	return ictx->queue;

  }
  
  static int cryptd_blkcipher_setkey(struct crypto_ablkcipher *parent,
  				   const u8 *key, unsigned int keylen)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_ablkcipher_ctx(parent);
  	struct crypto_blkcipher *child = ctx->child;
  	int err;
  
  	crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_blkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
  					  CRYPTO_TFM_REQ_MASK);
  	err = crypto_blkcipher_setkey(child, key, keylen);
  	crypto_ablkcipher_set_flags(parent, crypto_blkcipher_get_flags(child) &
  					    CRYPTO_TFM_RES_MASK);
  	return err;
  }
  
  static void cryptd_blkcipher_crypt(struct ablkcipher_request *req,
  				   struct crypto_blkcipher *child,
  				   int err,
  				   int (*crypt)(struct blkcipher_desc *desc,
  						struct scatterlist *dst,
  						struct scatterlist *src,
  						unsigned int len))
  {
  	struct cryptd_blkcipher_request_ctx *rctx;
  	struct blkcipher_desc desc;
  
  	rctx = ablkcipher_request_ctx(req);

  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  
  	desc.tfm = child;
  	desc.info = req->info;
  	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
  
  	err = crypt(&desc, req->dst, req->src, req->nbytes);
  
  	req->base.complete = rctx->complete;

  out:

  	local_bh_disable();

  	rctx->complete(&req->base, err);

  	local_bh_enable();
  }
  
  static void cryptd_blkcipher_encrypt(struct crypto_async_request *req, int err)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
  	struct crypto_blkcipher *child = ctx->child;
  
  	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
  			       crypto_blkcipher_crt(child)->encrypt);
  }
  
  static void cryptd_blkcipher_decrypt(struct crypto_async_request *req, int err)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
  	struct crypto_blkcipher *child = ctx->child;
  
  	cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
  			       crypto_blkcipher_crt(child)->decrypt);
  }
  
  static int cryptd_blkcipher_enqueue(struct ablkcipher_request *req,
  				    crypto_completion_t complete)
  {
  	struct cryptd_blkcipher_request_ctx *rctx = ablkcipher_request_ctx(req);
  	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);

  	struct cryptd_queue *queue;

  	queue = cryptd_get_queue(crypto_ablkcipher_tfm(tfm));

  	rctx->complete = req->base.complete;
  	req->base.complete = complete;

  	return cryptd_enqueue_request(queue, &req->base);

  }
  
  static int cryptd_blkcipher_encrypt_enqueue(struct ablkcipher_request *req)
  {
  	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_encrypt);
  }
  
  static int cryptd_blkcipher_decrypt_enqueue(struct ablkcipher_request *req)
  {
  	return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_decrypt);
  }
  
  static int cryptd_blkcipher_init_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  	struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
  	struct crypto_spawn *spawn = &ictx->spawn;
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
  	struct crypto_blkcipher *cipher;
  
  	cipher = crypto_spawn_blkcipher(spawn);
  	if (IS_ERR(cipher))
  		return PTR_ERR(cipher);
  
  	ctx->child = cipher;
  	tfm->crt_ablkcipher.reqsize =
  		sizeof(struct cryptd_blkcipher_request_ctx);
  	return 0;
  }
  
  static void cryptd_blkcipher_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);

  
  	crypto_free_blkcipher(ctx->child);
  }

  static void *cryptd_alloc_instance(struct crypto_alg *alg, unsigned int head,
  				   unsigned int tail)

  {

  	char *p;

  	struct crypto_instance *inst;

  	int err;

  	p = kzalloc(head + sizeof(*inst) + tail, GFP_KERNEL);
  	if (!p)
  		return ERR_PTR(-ENOMEM);
  
  	inst = (void *)(p + head);

  
  	err = -ENAMETOOLONG;
  	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  		     "cryptd(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
  		goto out_free_inst;

  	memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
  
  	inst->alg.cra_priority = alg->cra_priority + 50;
  	inst->alg.cra_blocksize = alg->cra_blocksize;
  	inst->alg.cra_alignmask = alg->cra_alignmask;
  
  out:

  	return p;

  
  out_free_inst:

  	kfree(p);
  	p = ERR_PTR(err);

  	goto out;
  }

  static int cryptd_create_blkcipher(struct crypto_template *tmpl,
  				   struct rtattr **tb,
  				   struct cryptd_queue *queue)

  {

  	struct cryptd_instance_ctx *ctx;

  	struct crypto_instance *inst;
  	struct crypto_alg *alg;

  	int err;

  
  	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_BLKCIPHER,

  				  CRYPTO_ALG_TYPE_MASK);

  	if (IS_ERR(alg))

  		return PTR_ERR(alg);

  	inst = cryptd_alloc_instance(alg, 0, sizeof(*ctx));

  	err = PTR_ERR(inst);

  	if (IS_ERR(inst))
  		goto out_put_alg;

  	ctx = crypto_instance_ctx(inst);
  	ctx->queue = queue;
  
  	err = crypto_init_spawn(&ctx->spawn, alg, inst,
  				CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
  	if (err)
  		goto out_free_inst;

  	inst->alg.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC;

  	inst->alg.cra_type = &crypto_ablkcipher_type;
  
  	inst->alg.cra_ablkcipher.ivsize = alg->cra_blkcipher.ivsize;
  	inst->alg.cra_ablkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
  	inst->alg.cra_ablkcipher.max_keysize = alg->cra_blkcipher.max_keysize;

  	inst->alg.cra_ablkcipher.geniv = alg->cra_blkcipher.geniv;

  	inst->alg.cra_ctxsize = sizeof(struct cryptd_blkcipher_ctx);
  
  	inst->alg.cra_init = cryptd_blkcipher_init_tfm;
  	inst->alg.cra_exit = cryptd_blkcipher_exit_tfm;
  
  	inst->alg.cra_ablkcipher.setkey = cryptd_blkcipher_setkey;
  	inst->alg.cra_ablkcipher.encrypt = cryptd_blkcipher_encrypt_enqueue;
  	inst->alg.cra_ablkcipher.decrypt = cryptd_blkcipher_decrypt_enqueue;

  	err = crypto_register_instance(tmpl, inst);
  	if (err) {
  		crypto_drop_spawn(&ctx->spawn);
  out_free_inst:
  		kfree(inst);
  	}

  out_put_alg:
  	crypto_mod_put(alg);

  	return err;

  }

  static int cryptd_hash_init_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);

  	struct hashd_instance_ctx *ictx = crypto_instance_ctx(inst);
  	struct crypto_shash_spawn *spawn = &ictx->spawn;

  	struct cryptd_hash_ctx *ctx = crypto_tfm_ctx(tfm);

  	struct crypto_shash *hash;

  	hash = crypto_spawn_shash(spawn);
  	if (IS_ERR(hash))
  		return PTR_ERR(hash);

  	ctx->child = hash;

  	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
  				 sizeof(struct cryptd_hash_request_ctx) +
  				 crypto_shash_descsize(hash));

  	return 0;
  }
  
  static void cryptd_hash_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct cryptd_hash_ctx *ctx = crypto_tfm_ctx(tfm);

  	crypto_free_shash(ctx->child);

  }
  
  static int cryptd_hash_setkey(struct crypto_ahash *parent,
  				   const u8 *key, unsigned int keylen)
  {
  	struct cryptd_hash_ctx *ctx   = crypto_ahash_ctx(parent);

  	struct crypto_shash *child = ctx->child;

  	int err;

  	crypto_shash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_shash_set_flags(child, crypto_ahash_get_flags(parent) &
  				      CRYPTO_TFM_REQ_MASK);
  	err = crypto_shash_setkey(child, key, keylen);
  	crypto_ahash_set_flags(parent, crypto_shash_get_flags(child) &
  				       CRYPTO_TFM_RES_MASK);

  	return err;
  }
  
  static int cryptd_hash_enqueue(struct ahash_request *req,
  				crypto_completion_t complete)
  {
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

  	struct cryptd_queue *queue =
  		cryptd_get_queue(crypto_ahash_tfm(tfm));

  
  	rctx->complete = req->base.complete;
  	req->base.complete = complete;

  	return cryptd_enqueue_request(queue, &req->base);

  }
  
  static void cryptd_hash_init(struct crypto_async_request *req_async, int err)
  {

  	struct cryptd_hash_ctx *ctx = crypto_tfm_ctx(req_async->tfm);
  	struct crypto_shash *child = ctx->child;
  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  	struct shash_desc *desc = &rctx->desc;

  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	desc->tfm = child;
  	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;

  	err = crypto_shash_init(desc);

  
  	req->base.complete = rctx->complete;
  
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int cryptd_hash_init_enqueue(struct ahash_request *req)
  {
  	return cryptd_hash_enqueue(req, cryptd_hash_init);
  }
  
  static void cryptd_hash_update(struct crypto_async_request *req_async, int err)
  {

  	struct ahash_request *req = ahash_request_cast(req_async);

  	struct cryptd_hash_request_ctx *rctx;

  
  	rctx = ahash_request_ctx(req);
  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	err = shash_ahash_update(req, &rctx->desc);

  
  	req->base.complete = rctx->complete;
  
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int cryptd_hash_update_enqueue(struct ahash_request *req)
  {
  	return cryptd_hash_enqueue(req, cryptd_hash_update);
  }
  
  static void cryptd_hash_final(struct crypto_async_request *req_async, int err)
  {

  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);

  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	err = crypto_shash_final(&rctx->desc, req->result);

  
  	req->base.complete = rctx->complete;
  
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int cryptd_hash_final_enqueue(struct ahash_request *req)
  {
  	return cryptd_hash_enqueue(req, cryptd_hash_final);
  }

  static void cryptd_hash_finup(struct crypto_async_request *req_async, int err)
  {
  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;
  
  	err = shash_ahash_finup(req, &rctx->desc);
  
  	req->base.complete = rctx->complete;
  
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int cryptd_hash_finup_enqueue(struct ahash_request *req)
  {
  	return cryptd_hash_enqueue(req, cryptd_hash_finup);
  }

  static void cryptd_hash_digest(struct crypto_async_request *req_async, int err)
  {

  	struct cryptd_hash_ctx *ctx = crypto_tfm_ctx(req_async->tfm);
  	struct crypto_shash *child = ctx->child;
  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  	struct shash_desc *desc = &rctx->desc;

  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	desc->tfm = child;
  	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;

  	err = shash_ahash_digest(req, desc);

  
  	req->base.complete = rctx->complete;
  
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int cryptd_hash_digest_enqueue(struct ahash_request *req)
  {
  	return cryptd_hash_enqueue(req, cryptd_hash_digest);
  }

  static int cryptd_hash_export(struct ahash_request *req, void *out)
  {
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  
  	return crypto_shash_export(&rctx->desc, out);
  }
  
  static int cryptd_hash_import(struct ahash_request *req, const void *in)
  {
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  
  	return crypto_shash_import(&rctx->desc, in);
  }

  static int cryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
  			      struct cryptd_queue *queue)

  {

  	struct hashd_instance_ctx *ctx;

  	struct ahash_instance *inst;

  	struct shash_alg *salg;

  	struct crypto_alg *alg;

  	int err;

  	salg = shash_attr_alg(tb[1], 0, 0);
  	if (IS_ERR(salg))

  		return PTR_ERR(salg);

  	alg = &salg->base;

  	inst = cryptd_alloc_instance(alg, ahash_instance_headroom(),
  				     sizeof(*ctx));

  	err = PTR_ERR(inst);

  	if (IS_ERR(inst))
  		goto out_put_alg;

  	ctx = ahash_instance_ctx(inst);

  	ctx->queue = queue;

  	err = crypto_init_shash_spawn(&ctx->spawn, salg,
  				      ahash_crypto_instance(inst));

  	if (err)
  		goto out_free_inst;

  	inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC;

  	inst->alg.halg.digestsize = salg->digestsize;
  	inst->alg.halg.base.cra_ctxsize = sizeof(struct cryptd_hash_ctx);

  	inst->alg.halg.base.cra_init = cryptd_hash_init_tfm;
  	inst->alg.halg.base.cra_exit = cryptd_hash_exit_tfm;

  	inst->alg.init   = cryptd_hash_init_enqueue;
  	inst->alg.update = cryptd_hash_update_enqueue;
  	inst->alg.final  = cryptd_hash_final_enqueue;

  	inst->alg.finup  = cryptd_hash_finup_enqueue;
  	inst->alg.export = cryptd_hash_export;
  	inst->alg.import = cryptd_hash_import;

  	inst->alg.setkey = cryptd_hash_setkey;
  	inst->alg.digest = cryptd_hash_digest_enqueue;

  	err = ahash_register_instance(tmpl, inst);

  	if (err) {
  		crypto_drop_shash(&ctx->spawn);
  out_free_inst:
  		kfree(inst);
  	}

  out_put_alg:
  	crypto_mod_put(alg);

  	return err;

  }

  static struct cryptd_queue queue;

  static int cryptd_create(struct crypto_template *tmpl, struct rtattr **tb)

  {
  	struct crypto_attr_type *algt;
  
  	algt = crypto_get_attr_type(tb);
  	if (IS_ERR(algt))

  		return PTR_ERR(algt);

  
  	switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
  	case CRYPTO_ALG_TYPE_BLKCIPHER:

  		return cryptd_create_blkcipher(tmpl, tb, &queue);

  	case CRYPTO_ALG_TYPE_DIGEST:

  		return cryptd_create_hash(tmpl, tb, &queue);

  	}

  	return -EINVAL;

  }
  
  static void cryptd_free(struct crypto_instance *inst)
  {
  	struct cryptd_instance_ctx *ctx = crypto_instance_ctx(inst);

  	struct hashd_instance_ctx *hctx = crypto_instance_ctx(inst);
  
  	switch (inst->alg.cra_flags & CRYPTO_ALG_TYPE_MASK) {
  	case CRYPTO_ALG_TYPE_AHASH:
  		crypto_drop_shash(&hctx->spawn);
  		kfree(ahash_instance(inst));
  		return;
  	}

  
  	crypto_drop_spawn(&ctx->spawn);
  	kfree(inst);
  }
  
  static struct crypto_template cryptd_tmpl = {
  	.name = "cryptd",

  	.create = cryptd_create,

  	.free = cryptd_free,
  	.module = THIS_MODULE,
  };

  struct cryptd_ablkcipher *cryptd_alloc_ablkcipher(const char *alg_name,
  						  u32 type, u32 mask)
  {
  	char cryptd_alg_name[CRYPTO_MAX_ALG_NAME];

  	struct crypto_tfm *tfm;

  
  	if (snprintf(cryptd_alg_name, CRYPTO_MAX_ALG_NAME,
  		     "cryptd(%s)", alg_name) >= CRYPTO_MAX_ALG_NAME)
  		return ERR_PTR(-EINVAL);

  	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
  	type |= CRYPTO_ALG_TYPE_BLKCIPHER;
  	mask &= ~CRYPTO_ALG_TYPE_MASK;
  	mask |= (CRYPTO_ALG_GENIV | CRYPTO_ALG_TYPE_BLKCIPHER_MASK);
  	tfm = crypto_alloc_base(cryptd_alg_name, type, mask);

  	if (IS_ERR(tfm))
  		return ERR_CAST(tfm);

  	if (tfm->__crt_alg->cra_module != THIS_MODULE) {
  		crypto_free_tfm(tfm);

  		return ERR_PTR(-EINVAL);
  	}

  	return __cryptd_ablkcipher_cast(__crypto_ablkcipher_cast(tfm));

  }
  EXPORT_SYMBOL_GPL(cryptd_alloc_ablkcipher);
  
  struct crypto_blkcipher *cryptd_ablkcipher_child(struct cryptd_ablkcipher *tfm)
  {
  	struct cryptd_blkcipher_ctx *ctx = crypto_ablkcipher_ctx(&tfm->base);
  	return ctx->child;
  }
  EXPORT_SYMBOL_GPL(cryptd_ablkcipher_child);
  
  void cryptd_free_ablkcipher(struct cryptd_ablkcipher *tfm)
  {
  	crypto_free_ablkcipher(&tfm->base);
  }
  EXPORT_SYMBOL_GPL(cryptd_free_ablkcipher);

  struct cryptd_ahash *cryptd_alloc_ahash(const char *alg_name,
  					u32 type, u32 mask)
  {
  	char cryptd_alg_name[CRYPTO_MAX_ALG_NAME];
  	struct crypto_ahash *tfm;
  
  	if (snprintf(cryptd_alg_name, CRYPTO_MAX_ALG_NAME,
  		     "cryptd(%s)", alg_name) >= CRYPTO_MAX_ALG_NAME)
  		return ERR_PTR(-EINVAL);
  	tfm = crypto_alloc_ahash(cryptd_alg_name, type, mask);
  	if (IS_ERR(tfm))
  		return ERR_CAST(tfm);
  	if (tfm->base.__crt_alg->cra_module != THIS_MODULE) {
  		crypto_free_ahash(tfm);
  		return ERR_PTR(-EINVAL);
  	}
  
  	return __cryptd_ahash_cast(tfm);
  }
  EXPORT_SYMBOL_GPL(cryptd_alloc_ahash);
  
  struct crypto_shash *cryptd_ahash_child(struct cryptd_ahash *tfm)
  {
  	struct cryptd_hash_ctx *ctx = crypto_ahash_ctx(&tfm->base);
  
  	return ctx->child;
  }
  EXPORT_SYMBOL_GPL(cryptd_ahash_child);

  struct shash_desc *cryptd_shash_desc(struct ahash_request *req)
  {
  	struct cryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  	return &rctx->desc;
  }
  EXPORT_SYMBOL_GPL(cryptd_shash_desc);

  void cryptd_free_ahash(struct cryptd_ahash *tfm)
  {
  	crypto_free_ahash(&tfm->base);
  }
  EXPORT_SYMBOL_GPL(cryptd_free_ahash);

  static int __init cryptd_init(void)
  {
  	int err;

  	err = cryptd_init_queue(&queue, CRYPTD_MAX_CPU_QLEN);

  	if (err)
  		return err;
  
  	err = crypto_register_template(&cryptd_tmpl);
  	if (err)

  		cryptd_fini_queue(&queue);

  
  	return err;
  }
  
  static void __exit cryptd_exit(void)
  {

  	cryptd_fini_queue(&queue);

  	crypto_unregister_template(&cryptd_tmpl);
  }
  
  module_init(cryptd_init);
  module_exit(cryptd_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Software async crypto daemon");