/*
   * Cryptographic API for algorithms (i.e., low-level API).
   *
   * 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 <linux/err.h>

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

  #include <linux/list.h>

  #include <linux/module.h>

  #include <linux/rtnetlink.h>

  #include <linux/slab.h>

  #include <linux/string.h>
  
  #include "internal.h"

  static LIST_HEAD(crypto_template_list);

  static inline int crypto_set_driver_name(struct crypto_alg *alg)
  {
  	static const char suffix[] = "-generic";
  	char *driver_name = alg->cra_driver_name;
  	int len;
  
  	if (*driver_name)
  		return 0;
  
  	len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
  	if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
  		return -ENAMETOOLONG;
  
  	memcpy(driver_name + len, suffix, sizeof(suffix));
  	return 0;
  }

  static int crypto_check_alg(struct crypto_alg *alg)

  {

  	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
  		return -EINVAL;

  	if (alg->cra_blocksize > PAGE_SIZE / 8)
  		return -EINVAL;
  
  	if (alg->cra_priority < 0)
  		return -EINVAL;

  	return crypto_set_driver_name(alg);
  }

  static void crypto_destroy_instance(struct crypto_alg *alg)
  {
  	struct crypto_instance *inst = (void *)alg;
  	struct crypto_template *tmpl = inst->tmpl;
  
  	tmpl->free(inst);
  	crypto_tmpl_put(tmpl);
  }

  static struct list_head *crypto_more_spawns(struct crypto_alg *alg,
  					    struct list_head *stack,
  					    struct list_head *top,
  					    struct list_head *secondary_spawns)
  {
  	struct crypto_spawn *spawn, *n;
  
  	if (list_empty(stack))
  		return NULL;
  
  	spawn = list_first_entry(stack, struct crypto_spawn, list);
  	n = list_entry(spawn->list.next, struct crypto_spawn, list);
  
  	if (spawn->alg && &n->list != stack && !n->alg)
  		n->alg = (n->list.next == stack) ? alg :
  			 &list_entry(n->list.next, struct crypto_spawn,
  				     list)->inst->alg;
  
  	list_move(&spawn->list, secondary_spawns);
  
  	return &n->list == stack ? top : &n->inst->alg.cra_users;
  }

  static void crypto_remove_spawn(struct crypto_spawn *spawn,

  				struct list_head *list)

  {

  	struct crypto_instance *inst = spawn->inst;
  	struct crypto_template *tmpl = inst->tmpl;

  	if (crypto_is_dead(&inst->alg))
  		return;

  	inst->alg.cra_flags |= CRYPTO_ALG_DEAD;

  	if (hlist_unhashed(&inst->list))
  		return;

  	if (!tmpl || !crypto_tmpl_get(tmpl))
  		return;
  
  	crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
  	list_move(&inst->alg.cra_list, list);
  	hlist_del(&inst->list);
  	inst->alg.cra_destroy = crypto_destroy_instance;

  	BUG_ON(!list_empty(&inst->alg.cra_users));

  }

  void crypto_remove_spawns(struct crypto_alg *alg, struct list_head *list,
  			  struct crypto_alg *nalg)

  {

  	u32 new_type = (nalg ?: alg)->cra_flags;

  	struct crypto_spawn *spawn, *n;
  	LIST_HEAD(secondary_spawns);

  	struct list_head *spawns;
  	LIST_HEAD(stack);
  	LIST_HEAD(top);

  	spawns = &alg->cra_users;

  	list_for_each_entry_safe(spawn, n, spawns, list) {
  		if ((spawn->alg->cra_flags ^ new_type) & spawn->mask)

  			continue;

  		list_move(&spawn->list, &top);

  	}

  	spawns = ⊤
  	do {
  		while (!list_empty(spawns)) {
  			struct crypto_instance *inst;
  
  			spawn = list_first_entry(spawns, struct crypto_spawn,
  						 list);
  			inst = spawn->inst;
  
  			BUG_ON(&inst->alg == alg);
  
  			list_move(&spawn->list, &stack);
  
  			if (&inst->alg == nalg)
  				break;
  
  			spawn->alg = NULL;
  			spawns = &inst->alg.cra_users;
  		}
  	} while ((spawns = crypto_more_spawns(alg, &stack, &top,
  					      &secondary_spawns)));
  
  	list_for_each_entry_safe(spawn, n, &secondary_spawns, list) {
  		if (spawn->alg)
  			list_move(&spawn->list, &spawn->alg->cra_users);
  		else
  			crypto_remove_spawn(spawn, list);

  	}
  }

  EXPORT_SYMBOL_GPL(crypto_remove_spawns);

  static struct crypto_larval *__crypto_register_alg(struct crypto_alg *alg)

  {
  	struct crypto_alg *q;

  	struct crypto_larval *larval;

  	int ret = -EAGAIN;
  
  	if (crypto_is_dead(alg))

  		goto err;

  
  	INIT_LIST_HEAD(&alg->cra_users);

  	/* No cheating! */
  	alg->cra_flags &= ~CRYPTO_ALG_TESTED;

  	ret = -EEXIST;

  	atomic_set(&alg->cra_refcnt, 1);

  	list_for_each_entry(q, &crypto_alg_list, cra_list) {

  		if (q == alg)

  			goto err;

  		if (crypto_is_moribund(q))
  			continue;

  		if (crypto_is_larval(q)) {
  			if (!strcmp(alg->cra_driver_name, q->cra_driver_name))
  				goto err;
  			continue;
  		}
  
  		if (!strcmp(q->cra_driver_name, alg->cra_name) ||
  		    !strcmp(q->cra_name, alg->cra_driver_name))
  			goto err;
  	}
  
  	larval = crypto_larval_alloc(alg->cra_name,
  				     alg->cra_flags | CRYPTO_ALG_TESTED, 0);
  	if (IS_ERR(larval))
  		goto out;
  
  	ret = -ENOENT;
  	larval->adult = crypto_mod_get(alg);
  	if (!larval->adult)
  		goto free_larval;
  
  	atomic_set(&larval->alg.cra_refcnt, 1);
  	memcpy(larval->alg.cra_driver_name, alg->cra_driver_name,
  	       CRYPTO_MAX_ALG_NAME);
  	larval->alg.cra_priority = alg->cra_priority;
  
  	list_add(&alg->cra_list, &crypto_alg_list);
  	list_add(&larval->alg.cra_list, &crypto_alg_list);

  out:

  	return larval;
  
  free_larval:
  	kfree(larval);
  err:
  	larval = ERR_PTR(ret);
  	goto out;
  }
  
  void crypto_alg_tested(const char *name, int err)
  {
  	struct crypto_larval *test;
  	struct crypto_alg *alg;
  	struct crypto_alg *q;
  	LIST_HEAD(list);
  
  	down_write(&crypto_alg_sem);
  	list_for_each_entry(q, &crypto_alg_list, cra_list) {

  		if (crypto_is_moribund(q) || !crypto_is_larval(q))

  			continue;
  
  		test = (struct crypto_larval *)q;
  
  		if (!strcmp(q->cra_driver_name, name))
  			goto found;
  	}
  
  	printk(KERN_ERR "alg: Unexpected test result for %s: %d
  ", name, err);
  	goto unlock;
  
  found:

  	q->cra_flags |= CRYPTO_ALG_DEAD;

  	alg = test->adult;
  	if (err || list_empty(&alg->cra_list))
  		goto complete;
  
  	alg->cra_flags |= CRYPTO_ALG_TESTED;
  
  	list_for_each_entry(q, &crypto_alg_list, cra_list) {
  		if (q == alg)
  			continue;

  
  		if (crypto_is_moribund(q))
  			continue;
  
  		if (crypto_is_larval(q)) {

  			struct crypto_larval *larval = (void *)q;

  			/*
  			 * Check to see if either our generic name or
  			 * specific name can satisfy the name requested
  			 * by the larval entry q.
  			 */

  			if (strcmp(alg->cra_name, q->cra_name) &&
  			    strcmp(alg->cra_driver_name, q->cra_name))
  				continue;
  
  			if (larval->adult)
  				continue;

  			if ((q->cra_flags ^ alg->cra_flags) & larval->mask)
  				continue;

  			if (!crypto_mod_get(alg))
  				continue;

  			larval->adult = alg;

  			continue;

  		}

  
  		if (strcmp(alg->cra_name, q->cra_name))
  			continue;
  
  		if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&
  		    q->cra_priority > alg->cra_priority)
  			continue;

  		crypto_remove_spawns(q, &list, alg);

  	}

  complete:
  	complete_all(&test->completion);

  unlock:
  	up_write(&crypto_alg_sem);
  
  	crypto_remove_final(&list);

  }

  EXPORT_SYMBOL_GPL(crypto_alg_tested);

  void crypto_remove_final(struct list_head *list)

  {
  	struct crypto_alg *alg;
  	struct crypto_alg *n;
  
  	list_for_each_entry_safe(alg, n, list, cra_list) {
  		list_del_init(&alg->cra_list);
  		crypto_alg_put(alg);
  	}
  }

  EXPORT_SYMBOL_GPL(crypto_remove_final);

  static void crypto_wait_for_test(struct crypto_larval *larval)
  {
  	int err;
  
  	err = crypto_probing_notify(CRYPTO_MSG_ALG_REGISTER, larval->adult);
  	if (err != NOTIFY_STOP) {
  		if (WARN_ON(err != NOTIFY_DONE))
  			goto out;
  		crypto_alg_tested(larval->alg.cra_driver_name, 0);
  	}
  
  	err = wait_for_completion_interruptible(&larval->completion);
  	WARN_ON(err);
  
  out:
  	crypto_larval_kill(&larval->alg);
  }

  int crypto_register_alg(struct crypto_alg *alg)
  {

  	struct crypto_larval *larval;

  	int err;
  
  	err = crypto_check_alg(alg);
  	if (err)
  		return err;
  
  	down_write(&crypto_alg_sem);

  	larval = __crypto_register_alg(alg);

  	up_write(&crypto_alg_sem);

  	if (IS_ERR(larval))
  		return PTR_ERR(larval);
  
  	crypto_wait_for_test(larval);
  	return 0;

  }

  EXPORT_SYMBOL_GPL(crypto_register_alg);

  static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
  {
  	if (unlikely(list_empty(&alg->cra_list)))
  		return -ENOENT;
  
  	alg->cra_flags |= CRYPTO_ALG_DEAD;
  
  	crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
  	list_del_init(&alg->cra_list);

  	crypto_remove_spawns(alg, list, NULL);

  
  	return 0;
  }

  int crypto_unregister_alg(struct crypto_alg *alg)
  {

  	int ret;
  	LIST_HEAD(list);

  	down_write(&crypto_alg_sem);

  	ret = crypto_remove_alg(alg, &list);

  	up_write(&crypto_alg_sem);
  
  	if (ret)
  		return ret;
  
  	BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
  	if (alg->cra_destroy)
  		alg->cra_destroy(alg);

  	crypto_remove_final(&list);

  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_alg);

  int crypto_register_algs(struct crypto_alg *algs, int count)
  {
  	int i, ret;
  
  	for (i = 0; i < count; i++) {
  		ret = crypto_register_alg(&algs[i]);
  		if (ret)
  			goto err;
  	}
  
  	return 0;
  
  err:
  	for (--i; i >= 0; --i)
  		crypto_unregister_alg(&algs[i]);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(crypto_register_algs);
  
  int crypto_unregister_algs(struct crypto_alg *algs, int count)
  {
  	int i, ret;
  
  	for (i = 0; i < count; i++) {
  		ret = crypto_unregister_alg(&algs[i]);
  		if (ret)
  			pr_err("Failed to unregister %s %s: %d
  ",
  			       algs[i].cra_driver_name, algs[i].cra_name, ret);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_algs);

  int crypto_register_template(struct crypto_template *tmpl)
  {
  	struct crypto_template *q;
  	int err = -EEXIST;
  
  	down_write(&crypto_alg_sem);
  
  	list_for_each_entry(q, &crypto_template_list, list) {
  		if (q == tmpl)
  			goto out;
  	}
  
  	list_add(&tmpl->list, &crypto_template_list);

  	crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);

  	err = 0;
  out:
  	up_write(&crypto_alg_sem);
  	return err;
  }
  EXPORT_SYMBOL_GPL(crypto_register_template);
  
  void crypto_unregister_template(struct crypto_template *tmpl)
  {
  	struct crypto_instance *inst;

  	struct hlist_node *n;

  	struct hlist_head *list;

  	LIST_HEAD(users);

  
  	down_write(&crypto_alg_sem);
  
  	BUG_ON(list_empty(&tmpl->list));
  	list_del_init(&tmpl->list);
  
  	list = &tmpl->instances;

  	hlist_for_each_entry(inst, list, list) {

  		int err = crypto_remove_alg(&inst->alg, &users);
  		BUG_ON(err);

  	}

  	crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);

  	up_write(&crypto_alg_sem);

  	hlist_for_each_entry_safe(inst, n, list, list) {

  		BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
  		tmpl->free(inst);
  	}

  	crypto_remove_final(&users);

  }
  EXPORT_SYMBOL_GPL(crypto_unregister_template);
  
  static struct crypto_template *__crypto_lookup_template(const char *name)
  {
  	struct crypto_template *q, *tmpl = NULL;
  
  	down_read(&crypto_alg_sem);
  	list_for_each_entry(q, &crypto_template_list, list) {
  		if (strcmp(q->name, name))
  			continue;
  		if (unlikely(!crypto_tmpl_get(q)))
  			continue;
  
  		tmpl = q;
  		break;
  	}
  	up_read(&crypto_alg_sem);
  
  	return tmpl;
  }
  
  struct crypto_template *crypto_lookup_template(const char *name)
  {

  	return try_then_request_module(__crypto_lookup_template(name), "%s",
  				       name);

  }
  EXPORT_SYMBOL_GPL(crypto_lookup_template);
  
  int crypto_register_instance(struct crypto_template *tmpl,
  			     struct crypto_instance *inst)
  {

  	struct crypto_larval *larval;
  	int err;

  	err = crypto_check_alg(&inst->alg);
  	if (err)
  		goto err;
  
  	inst->alg.cra_module = tmpl->module;

  	inst->alg.cra_flags |= CRYPTO_ALG_INSTANCE;

  
  	down_write(&crypto_alg_sem);

  	larval = __crypto_register_alg(&inst->alg);
  	if (IS_ERR(larval))

  		goto unlock;
  
  	hlist_add_head(&inst->list, &tmpl->instances);
  	inst->tmpl = tmpl;
  
  unlock:
  	up_write(&crypto_alg_sem);

  	err = PTR_ERR(larval);
  	if (IS_ERR(larval))
  		goto err;
  
  	crypto_wait_for_test(larval);
  	err = 0;

  err:
  	return err;
  }
  EXPORT_SYMBOL_GPL(crypto_register_instance);

  
  int crypto_unregister_instance(struct crypto_alg *alg)
  {
  	int err;
  	struct crypto_instance *inst = (void *)alg;
  	struct crypto_template *tmpl = inst->tmpl;
  	LIST_HEAD(users);
  
  	if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
  		return -EINVAL;
  
  	BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
  
  	down_write(&crypto_alg_sem);
  
  	hlist_del_init(&inst->list);
  	err = crypto_remove_alg(alg, &users);
  
  	up_write(&crypto_alg_sem);
  
  	if (err)
  		return err;
  
  	tmpl->free(inst);
  	crypto_remove_final(&users);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_instance);

  int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,

  		      struct crypto_instance *inst, u32 mask)

  {
  	int err = -EAGAIN;
  
  	spawn->inst = inst;

  	spawn->mask = mask;

  
  	down_write(&crypto_alg_sem);
  	if (!crypto_is_moribund(alg)) {
  		list_add(&spawn->list, &alg->cra_users);
  		spawn->alg = alg;
  		err = 0;
  	}
  	up_write(&crypto_alg_sem);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(crypto_init_spawn);

  int crypto_init_spawn2(struct crypto_spawn *spawn, struct crypto_alg *alg,
  		       struct crypto_instance *inst,
  		       const struct crypto_type *frontend)
  {
  	int err = -EINVAL;

  	if ((alg->cra_flags ^ frontend->type) & frontend->maskset)

  		goto out;
  
  	spawn->frontend = frontend;
  	err = crypto_init_spawn(spawn, alg, inst, frontend->maskset);
  
  out:
  	return err;
  }
  EXPORT_SYMBOL_GPL(crypto_init_spawn2);

  void crypto_drop_spawn(struct crypto_spawn *spawn)
  {

  	if (!spawn->alg)
  		return;

  	down_write(&crypto_alg_sem);
  	list_del(&spawn->list);
  	up_write(&crypto_alg_sem);
  }
  EXPORT_SYMBOL_GPL(crypto_drop_spawn);

  static struct crypto_alg *crypto_spawn_alg(struct crypto_spawn *spawn)

  {
  	struct crypto_alg *alg;
  	struct crypto_alg *alg2;

  
  	down_read(&crypto_alg_sem);
  	alg = spawn->alg;
  	alg2 = alg;
  	if (alg2)
  		alg2 = crypto_mod_get(alg2);
  	up_read(&crypto_alg_sem);
  
  	if (!alg2) {
  		if (alg)
  			crypto_shoot_alg(alg);
  		return ERR_PTR(-EAGAIN);
  	}

  	return alg;
  }
  
  struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn, u32 type,
  				    u32 mask)
  {
  	struct crypto_alg *alg;
  	struct crypto_tfm *tfm;
  
  	alg = crypto_spawn_alg(spawn);
  	if (IS_ERR(alg))
  		return ERR_CAST(alg);

  	tfm = ERR_PTR(-EINVAL);
  	if (unlikely((alg->cra_flags ^ type) & mask))
  		goto out_put_alg;

  	tfm = __crypto_alloc_tfm(alg, type, mask);

  	if (IS_ERR(tfm))

  		goto out_put_alg;
  
  	return tfm;

  out_put_alg:
  	crypto_mod_put(alg);

  	return tfm;
  }
  EXPORT_SYMBOL_GPL(crypto_spawn_tfm);

  void *crypto_spawn_tfm2(struct crypto_spawn *spawn)
  {
  	struct crypto_alg *alg;
  	struct crypto_tfm *tfm;
  
  	alg = crypto_spawn_alg(spawn);
  	if (IS_ERR(alg))
  		return ERR_CAST(alg);
  
  	tfm = crypto_create_tfm(alg, spawn->frontend);
  	if (IS_ERR(tfm))
  		goto out_put_alg;
  
  	return tfm;
  
  out_put_alg:
  	crypto_mod_put(alg);
  	return tfm;
  }
  EXPORT_SYMBOL_GPL(crypto_spawn_tfm2);

  int crypto_register_notifier(struct notifier_block *nb)
  {
  	return blocking_notifier_chain_register(&crypto_chain, nb);
  }
  EXPORT_SYMBOL_GPL(crypto_register_notifier);
  
  int crypto_unregister_notifier(struct notifier_block *nb)
  {
  	return blocking_notifier_chain_unregister(&crypto_chain, nb);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_notifier);

  struct crypto_attr_type *crypto_get_attr_type(struct rtattr **tb)

  {

  	struct rtattr *rta = tb[0];

  	struct crypto_attr_type *algt;
  
  	if (!rta)
  		return ERR_PTR(-ENOENT);
  	if (RTA_PAYLOAD(rta) < sizeof(*algt))
  		return ERR_PTR(-EINVAL);

  	if (rta->rta_type != CRYPTOA_TYPE)
  		return ERR_PTR(-EINVAL);

  
  	algt = RTA_DATA(rta);
  
  	return algt;
  }
  EXPORT_SYMBOL_GPL(crypto_get_attr_type);
  
  int crypto_check_attr_type(struct rtattr **tb, u32 type)
  {
  	struct crypto_attr_type *algt;
  
  	algt = crypto_get_attr_type(tb);
  	if (IS_ERR(algt))
  		return PTR_ERR(algt);
  
  	if ((algt->type ^ type) & algt->mask)
  		return -EINVAL;
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_check_attr_type);

  const char *crypto_attr_alg_name(struct rtattr *rta)

  {

  	struct crypto_attr_alg *alga;

  	if (!rta)
  		return ERR_PTR(-ENOENT);
  	if (RTA_PAYLOAD(rta) < sizeof(*alga))

  		return ERR_PTR(-EINVAL);

  	if (rta->rta_type != CRYPTOA_ALG)
  		return ERR_PTR(-EINVAL);

  
  	alga = RTA_DATA(rta);
  	alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;

  	return alga->name;
  }
  EXPORT_SYMBOL_GPL(crypto_attr_alg_name);

  struct crypto_alg *crypto_attr_alg2(struct rtattr *rta,
  				    const struct crypto_type *frontend,
  				    u32 type, u32 mask)

  {
  	const char *name;

  
  	name = crypto_attr_alg_name(rta);

  	if (IS_ERR(name))

  		return ERR_CAST(name);

  	return crypto_find_alg(name, frontend, type, mask);

  }

  EXPORT_SYMBOL_GPL(crypto_attr_alg2);

  
  int crypto_attr_u32(struct rtattr *rta, u32 *num)
  {
  	struct crypto_attr_u32 *nu32;
  
  	if (!rta)
  		return -ENOENT;
  	if (RTA_PAYLOAD(rta) < sizeof(*nu32))
  		return -EINVAL;
  	if (rta->rta_type != CRYPTOA_U32)
  		return -EINVAL;
  
  	nu32 = RTA_DATA(rta);
  	*num = nu32->num;
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_attr_u32);

  void *crypto_alloc_instance2(const char *name, struct crypto_alg *alg,
  			     unsigned int head)

  {
  	struct crypto_instance *inst;

  	char *p;

  	int err;

  	p = kzalloc(head + sizeof(*inst) + sizeof(struct crypto_spawn),
  		    GFP_KERNEL);
  	if (!p)

  		return ERR_PTR(-ENOMEM);

  	inst = (void *)(p + head);

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

  	return p;
  
  err_free_inst:
  	kfree(p);
  	return ERR_PTR(err);
  }
  EXPORT_SYMBOL_GPL(crypto_alloc_instance2);
  
  struct crypto_instance *crypto_alloc_instance(const char *name,
  					      struct crypto_alg *alg)
  {
  	struct crypto_instance *inst;
  	struct crypto_spawn *spawn;
  	int err;
  
  	inst = crypto_alloc_instance2(name, alg, 0);
  	if (IS_ERR(inst))
  		goto out;

  	spawn = crypto_instance_ctx(inst);

  	err = crypto_init_spawn(spawn, alg, inst,
  				CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);

  
  	if (err)
  		goto err_free_inst;
  
  	return inst;
  
  err_free_inst:
  	kfree(inst);

  	inst = ERR_PTR(err);
  
  out:
  	return inst;

  }
  EXPORT_SYMBOL_GPL(crypto_alloc_instance);

  void crypto_init_queue(struct crypto_queue *queue, unsigned int max_qlen)
  {
  	INIT_LIST_HEAD(&queue->list);
  	queue->backlog = &queue->list;
  	queue->qlen = 0;
  	queue->max_qlen = max_qlen;
  }
  EXPORT_SYMBOL_GPL(crypto_init_queue);
  
  int crypto_enqueue_request(struct crypto_queue *queue,
  			   struct crypto_async_request *request)
  {
  	int err = -EINPROGRESS;
  
  	if (unlikely(queue->qlen >= queue->max_qlen)) {
  		err = -EBUSY;
  		if (!(request->flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
  			goto out;
  		if (queue->backlog == &queue->list)
  			queue->backlog = &request->list;
  	}
  
  	queue->qlen++;
  	list_add_tail(&request->list, &queue->list);
  
  out:
  	return err;
  }
  EXPORT_SYMBOL_GPL(crypto_enqueue_request);

  void *__crypto_dequeue_request(struct crypto_queue *queue, unsigned int offset)

  {
  	struct list_head *request;
  
  	if (unlikely(!queue->qlen))
  		return NULL;
  
  	queue->qlen--;
  
  	if (queue->backlog != &queue->list)
  		queue->backlog = queue->backlog->next;
  
  	request = queue->list.next;
  	list_del(request);

  	return (char *)list_entry(request, struct crypto_async_request, list) -
  	       offset;
  }
  EXPORT_SYMBOL_GPL(__crypto_dequeue_request);
  
  struct crypto_async_request *crypto_dequeue_request(struct crypto_queue *queue)
  {
  	return __crypto_dequeue_request(queue, 0);

  }
  EXPORT_SYMBOL_GPL(crypto_dequeue_request);
  
  int crypto_tfm_in_queue(struct crypto_queue *queue, struct crypto_tfm *tfm)
  {
  	struct crypto_async_request *req;
  
  	list_for_each_entry(req, &queue->list, list) {
  		if (req->tfm == tfm)
  			return 1;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_tfm_in_queue);

  static inline void crypto_inc_byte(u8 *a, unsigned int size)
  {
  	u8 *b = (a + size);
  	u8 c;
  
  	for (; size; size--) {
  		c = *--b + 1;
  		*b = c;
  		if (c)
  			break;
  	}
  }
  
  void crypto_inc(u8 *a, unsigned int size)
  {
  	__be32 *b = (__be32 *)(a + size);
  	u32 c;
  
  	for (; size >= 4; size -= 4) {
  		c = be32_to_cpu(*--b) + 1;
  		*b = cpu_to_be32(c);
  		if (c)
  			return;
  	}
  
  	crypto_inc_byte(a, size);
  }
  EXPORT_SYMBOL_GPL(crypto_inc);
  
  static inline void crypto_xor_byte(u8 *a, const u8 *b, unsigned int size)
  {
  	for (; size; size--)
  		*a++ ^= *b++;
  }
  
  void crypto_xor(u8 *dst, const u8 *src, unsigned int size)
  {
  	u32 *a = (u32 *)dst;
  	u32 *b = (u32 *)src;
  
  	for (; size >= 4; size -= 4)
  		*a++ ^= *b++;
  
  	crypto_xor_byte((u8 *)a, (u8 *)b, size);
  }
  EXPORT_SYMBOL_GPL(crypto_xor);

  static int __init crypto_algapi_init(void)
  {
  	crypto_init_proc();
  	return 0;
  }
  
  static void __exit crypto_algapi_exit(void)
  {
  	crypto_exit_proc();
  }
  
  module_init(crypto_algapi_init);
  module_exit(crypto_algapi_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Cryptographic algorithms API");