/*
   * Software multibuffer async crypto daemon.
   *
   * Copyright (c) 2014 Tim Chen <tim.c.chen@linux.intel.com>
   *
   * Adapted from crypto daemon.
   *
   * 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/internal/aead.h>
  #include <crypto/mcryptd.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/sched/stat.h>

  #include <linux/slab.h>

  
  #define MCRYPTD_MAX_CPU_QLEN 100
  #define MCRYPTD_BATCH 9
  
  static void *mcryptd_alloc_instance(struct crypto_alg *alg, unsigned int head,
  				   unsigned int tail);
  
  struct mcryptd_flush_list {
  	struct list_head list;
  	struct mutex lock;
  };

  static struct mcryptd_flush_list __percpu *mcryptd_flist;

  
  struct hashd_instance_ctx {

  	struct crypto_ahash_spawn spawn;

  	struct mcryptd_queue *queue;
  };
  
  static void mcryptd_queue_worker(struct work_struct *work);
  
  void mcryptd_arm_flusher(struct mcryptd_alg_cstate *cstate, unsigned long delay)
  {
  	struct mcryptd_flush_list *flist;
  
  	if (!cstate->flusher_engaged) {
  		/* put the flusher on the flush list */
  		flist = per_cpu_ptr(mcryptd_flist, smp_processor_id());
  		mutex_lock(&flist->lock);
  		list_add_tail(&cstate->flush_list, &flist->list);
  		cstate->flusher_engaged = true;
  		cstate->next_flush = jiffies + delay;
  		queue_delayed_work_on(smp_processor_id(), kcrypto_wq,
  			&cstate->flush, delay);
  		mutex_unlock(&flist->lock);
  	}
  }
  EXPORT_SYMBOL(mcryptd_arm_flusher);
  
  static int mcryptd_init_queue(struct mcryptd_queue *queue,
  			     unsigned int max_cpu_qlen)
  {
  	int cpu;
  	struct mcryptd_cpu_queue *cpu_queue;
  
  	queue->cpu_queue = alloc_percpu(struct mcryptd_cpu_queue);
  	pr_debug("mqueue:%p mcryptd_cpu_queue %p
  ", queue, queue->cpu_queue);
  	if (!queue->cpu_queue)
  		return -ENOMEM;
  	for_each_possible_cpu(cpu) {
  		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
  		pr_debug("cpu_queue #%d %p
  ", cpu, queue->cpu_queue);
  		crypto_init_queue(&cpu_queue->queue, max_cpu_qlen);
  		INIT_WORK(&cpu_queue->work, mcryptd_queue_worker);

  		spin_lock_init(&cpu_queue->q_lock);

  	}
  	return 0;
  }
  
  static void mcryptd_fini_queue(struct mcryptd_queue *queue)
  {
  	int cpu;
  	struct mcryptd_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 mcryptd_enqueue_request(struct mcryptd_queue *queue,
  				  struct crypto_async_request *request,
  				  struct mcryptd_hash_request_ctx *rctx)
  {
  	int cpu, err;
  	struct mcryptd_cpu_queue *cpu_queue;

  	cpu_queue = raw_cpu_ptr(queue->cpu_queue);
  	spin_lock(&cpu_queue->q_lock);
  	cpu = smp_processor_id();
  	rctx->tag.cpu = smp_processor_id();

  
  	err = crypto_enqueue_request(&cpu_queue->queue, request);
  	pr_debug("enqueue request: cpu %d cpu_queue %p request %p
  ",
  		 cpu, cpu_queue, request);

  	spin_unlock(&cpu_queue->q_lock);

  	queue_work_on(cpu, kcrypto_wq, &cpu_queue->work);

  
  	return err;
  }
  
  /*
   * Try to opportunisticlly flush the partially completed jobs if
   * crypto daemon is the only task running.
   */
  static void mcryptd_opportunistic_flush(void)
  {
  	struct mcryptd_flush_list *flist;
  	struct mcryptd_alg_cstate *cstate;
  
  	flist = per_cpu_ptr(mcryptd_flist, smp_processor_id());
  	while (single_task_running()) {
  		mutex_lock(&flist->lock);

  		cstate = list_first_entry_or_null(&flist->list,

  				struct mcryptd_alg_cstate, flush_list);

  		if (!cstate || !cstate->flusher_engaged) {

  			mutex_unlock(&flist->lock);
  			return;
  		}
  		list_del(&cstate->flush_list);
  		cstate->flusher_engaged = false;
  		mutex_unlock(&flist->lock);
  		cstate->alg_state->flusher(cstate);
  	}
  }
  
  /*
   * Called in workqueue context, do one real cryption work (via
   * req->complete) and reschedule itself if there are more work to
   * do.
   */
  static void mcryptd_queue_worker(struct work_struct *work)
  {
  	struct mcryptd_cpu_queue *cpu_queue;
  	struct crypto_async_request *req, *backlog;
  	int i;
  
  	/*
  	 * Need to loop through more than once for multi-buffer to
  	 * be effective.
  	 */
  
  	cpu_queue = container_of(work, struct mcryptd_cpu_queue, work);
  	i = 0;
  	while (i < MCRYPTD_BATCH || single_task_running()) {

  
  		spin_lock_bh(&cpu_queue->q_lock);

  		backlog = crypto_get_backlog(&cpu_queue->queue);
  		req = crypto_dequeue_request(&cpu_queue->queue);

  		spin_unlock_bh(&cpu_queue->q_lock);

  
  		if (!req) {
  			mcryptd_opportunistic_flush();
  			return;
  		}
  
  		if (backlog)
  			backlog->complete(backlog, -EINPROGRESS);
  		req->complete(req, 0);
  		if (!cpu_queue->queue.qlen)
  			return;
  		++i;
  	}
  	if (cpu_queue->queue.qlen)

  		queue_work_on(smp_processor_id(), kcrypto_wq, &cpu_queue->work);

  }
  
  void mcryptd_flusher(struct work_struct *__work)
  {
  	struct	mcryptd_alg_cstate	*alg_cpu_state;
  	struct	mcryptd_alg_state	*alg_state;
  	struct	mcryptd_flush_list	*flist;
  	int	cpu;
  
  	cpu = smp_processor_id();
  	alg_cpu_state = container_of(to_delayed_work(__work),
  				     struct mcryptd_alg_cstate, flush);
  	alg_state = alg_cpu_state->alg_state;
  	if (alg_cpu_state->cpu != cpu)
  		pr_debug("mcryptd error: work on cpu %d, should be cpu %d
  ",
  				cpu, alg_cpu_state->cpu);
  
  	if (alg_cpu_state->flusher_engaged) {
  		flist = per_cpu_ptr(mcryptd_flist, cpu);
  		mutex_lock(&flist->lock);
  		list_del(&alg_cpu_state->flush_list);
  		alg_cpu_state->flusher_engaged = false;
  		mutex_unlock(&flist->lock);
  		alg_state->flusher(alg_cpu_state);
  	}
  }
  EXPORT_SYMBOL_GPL(mcryptd_flusher);
  
  static inline struct mcryptd_queue *mcryptd_get_queue(struct crypto_tfm *tfm)
  {
  	struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  	struct mcryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
  
  	return ictx->queue;
  }
  
  static void *mcryptd_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,
  		    "mcryptd(%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 inline bool mcryptd_check_internal(struct rtattr **tb, u32 *type,

  					  u32 *mask)
  {
  	struct crypto_attr_type *algt;
  
  	algt = crypto_get_attr_type(tb);
  	if (IS_ERR(algt))

  		return false;
  
  	*type |= algt->type & CRYPTO_ALG_INTERNAL;
  	*mask |= algt->mask & CRYPTO_ALG_INTERNAL;
  
  	if (*type & *mask & CRYPTO_ALG_INTERNAL)
  		return true;
  	else
  		return false;

  }

  static int mcryptd_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_ahash_spawn *spawn = &ictx->spawn;

  	struct mcryptd_hash_ctx *ctx = crypto_tfm_ctx(tfm);

  	struct crypto_ahash *hash;

  	hash = crypto_spawn_ahash(spawn);

  	if (IS_ERR(hash))
  		return PTR_ERR(hash);
  
  	ctx->child = hash;
  	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
  				 sizeof(struct mcryptd_hash_request_ctx) +

  				 crypto_ahash_reqsize(hash));

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

  	crypto_free_ahash(ctx->child);

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

  	struct crypto_ahash *child = ctx->child;

  	int err;

  	crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_ahash_set_flags(child, crypto_ahash_get_flags(parent) &

  				      CRYPTO_TFM_REQ_MASK);

  	err = crypto_ahash_setkey(child, key, keylen);
  	crypto_ahash_set_flags(parent, crypto_ahash_get_flags(child) &

  				       CRYPTO_TFM_RES_MASK);
  	return err;
  }
  
  static int mcryptd_hash_enqueue(struct ahash_request *req,
  				crypto_completion_t complete)
  {
  	int ret;
  
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	struct mcryptd_queue *queue =
  		mcryptd_get_queue(crypto_ahash_tfm(tfm));
  
  	rctx->complete = req->base.complete;
  	req->base.complete = complete;
  
  	ret = mcryptd_enqueue_request(queue, &req->base, rctx);
  
  	return ret;
  }
  
  static void mcryptd_hash_init(struct crypto_async_request *req_async, int err)
  {
  	struct mcryptd_hash_ctx *ctx = crypto_tfm_ctx(req_async->tfm);

  	struct crypto_ahash *child = ctx->child;

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

  	struct ahash_request *desc = &rctx->areq;

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

  	ahash_request_set_tfm(desc, child);
  	ahash_request_set_callback(desc, CRYPTO_TFM_REQ_MAY_SLEEP,
  						rctx->complete, req_async);

  	rctx->out = req->result;
  	err = crypto_ahash_init(desc);

  
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int mcryptd_hash_init_enqueue(struct ahash_request *req)
  {
  	return mcryptd_hash_enqueue(req, mcryptd_hash_init);
  }
  
  static void mcryptd_hash_update(struct crypto_async_request *req_async, int err)
  {
  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	rctx->out = req->result;

  	err = crypto_ahash_update(&rctx->areq);

  	if (err) {
  		req->base.complete = rctx->complete;
  		goto out;
  	}
  
  	return;
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int mcryptd_hash_update_enqueue(struct ahash_request *req)
  {
  	return mcryptd_hash_enqueue(req, mcryptd_hash_update);
  }
  
  static void mcryptd_hash_final(struct crypto_async_request *req_async, int err)
  {
  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	rctx->out = req->result;

  	err = crypto_ahash_final(&rctx->areq);

  	if (err) {
  		req->base.complete = rctx->complete;
  		goto out;
  	}
  
  	return;
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int mcryptd_hash_final_enqueue(struct ahash_request *req)
  {
  	return mcryptd_hash_enqueue(req, mcryptd_hash_final);
  }
  
  static void mcryptd_hash_finup(struct crypto_async_request *req_async, int err)
  {
  	struct ahash_request *req = ahash_request_cast(req_async);
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);
  
  	if (unlikely(err == -EINPROGRESS))
  		goto out;

  	rctx->out = req->result;

  	err = crypto_ahash_finup(&rctx->areq);

  
  	if (err) {
  		req->base.complete = rctx->complete;
  		goto out;
  	}
  
  	return;
  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int mcryptd_hash_finup_enqueue(struct ahash_request *req)
  {
  	return mcryptd_hash_enqueue(req, mcryptd_hash_finup);
  }
  
  static void mcryptd_hash_digest(struct crypto_async_request *req_async, int err)
  {
  	struct mcryptd_hash_ctx *ctx = crypto_tfm_ctx(req_async->tfm);

  	struct crypto_ahash *child = ctx->child;

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

  	struct ahash_request *desc = &rctx->areq;

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

  	ahash_request_set_tfm(desc, child);
  	ahash_request_set_callback(desc, CRYPTO_TFM_REQ_MAY_SLEEP,
  						rctx->complete, req_async);

  	rctx->out = req->result;

  	err = crypto_ahash_init(desc) ?: crypto_ahash_finup(desc);

  out:
  	local_bh_disable();
  	rctx->complete(&req->base, err);
  	local_bh_enable();
  }
  
  static int mcryptd_hash_digest_enqueue(struct ahash_request *req)
  {
  	return mcryptd_hash_enqueue(req, mcryptd_hash_digest);
  }
  
  static int mcryptd_hash_export(struct ahash_request *req, void *out)
  {
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);

  	return crypto_ahash_export(&rctx->areq, out);

  }
  
  static int mcryptd_hash_import(struct ahash_request *req, const void *in)
  {
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);

  	return crypto_ahash_import(&rctx->areq, in);

  }
  
  static int mcryptd_create_hash(struct crypto_template *tmpl, struct rtattr **tb,
  			      struct mcryptd_queue *queue)
  {
  	struct hashd_instance_ctx *ctx;
  	struct ahash_instance *inst;

  	struct hash_alg_common *halg;

  	struct crypto_alg *alg;

  	u32 type = 0;
  	u32 mask = 0;

  	int err;

  	if (!mcryptd_check_internal(tb, &type, &mask))
  		return -EINVAL;

  	halg = ahash_attr_alg(tb[1], type, mask);
  	if (IS_ERR(halg))
  		return PTR_ERR(halg);

  	alg = &halg->base;

  	pr_debug("crypto: mcryptd hash alg: %s
  ", alg->cra_name);
  	inst = mcryptd_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_ahash_spawn(&ctx->spawn, halg,

  				      ahash_crypto_instance(inst));
  	if (err)
  		goto out_free_inst;

  	inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC |
  		(alg->cra_flags & (CRYPTO_ALG_INTERNAL |
  				   CRYPTO_ALG_OPTIONAL_KEY));

  	inst->alg.halg.digestsize = halg->digestsize;
  	inst->alg.halg.statesize = halg->statesize;

  	inst->alg.halg.base.cra_ctxsize = sizeof(struct mcryptd_hash_ctx);
  
  	inst->alg.halg.base.cra_init = mcryptd_hash_init_tfm;
  	inst->alg.halg.base.cra_exit = mcryptd_hash_exit_tfm;
  
  	inst->alg.init   = mcryptd_hash_init_enqueue;
  	inst->alg.update = mcryptd_hash_update_enqueue;
  	inst->alg.final  = mcryptd_hash_final_enqueue;
  	inst->alg.finup  = mcryptd_hash_finup_enqueue;
  	inst->alg.export = mcryptd_hash_export;
  	inst->alg.import = mcryptd_hash_import;

  	if (crypto_hash_alg_has_setkey(halg))
  		inst->alg.setkey = mcryptd_hash_setkey;

  	inst->alg.digest = mcryptd_hash_digest_enqueue;
  
  	err = ahash_register_instance(tmpl, inst);
  	if (err) {

  		crypto_drop_ahash(&ctx->spawn);

  out_free_inst:
  		kfree(inst);
  	}
  
  out_put_alg:
  	crypto_mod_put(alg);
  	return err;
  }
  
  static struct mcryptd_queue mqueue;
  
  static int mcryptd_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_DIGEST:
  		return mcryptd_create_hash(tmpl, tb, &mqueue);
  	break;
  	}
  
  	return -EINVAL;
  }
  
  static void mcryptd_free(struct crypto_instance *inst)
  {
  	struct mcryptd_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_ahash(&hctx->spawn);

  		kfree(ahash_instance(inst));
  		return;
  	default:
  		crypto_drop_spawn(&ctx->spawn);
  		kfree(inst);
  	}
  }
  
  static struct crypto_template mcryptd_tmpl = {
  	.name = "mcryptd",
  	.create = mcryptd_create,
  	.free = mcryptd_free,
  	.module = THIS_MODULE,
  };
  
  struct mcryptd_ahash *mcryptd_alloc_ahash(const char *alg_name,
  					u32 type, u32 mask)
  {
  	char mcryptd_alg_name[CRYPTO_MAX_ALG_NAME];
  	struct crypto_ahash *tfm;
  
  	if (snprintf(mcryptd_alg_name, CRYPTO_MAX_ALG_NAME,
  		     "mcryptd(%s)", alg_name) >= CRYPTO_MAX_ALG_NAME)
  		return ERR_PTR(-EINVAL);
  	tfm = crypto_alloc_ahash(mcryptd_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 __mcryptd_ahash_cast(tfm);
  }
  EXPORT_SYMBOL_GPL(mcryptd_alloc_ahash);

  struct crypto_ahash *mcryptd_ahash_child(struct mcryptd_ahash *tfm)

  {
  	struct mcryptd_hash_ctx *ctx = crypto_ahash_ctx(&tfm->base);
  
  	return ctx->child;
  }
  EXPORT_SYMBOL_GPL(mcryptd_ahash_child);

  struct ahash_request *mcryptd_ahash_desc(struct ahash_request *req)

  {
  	struct mcryptd_hash_request_ctx *rctx = ahash_request_ctx(req);

  	return &rctx->areq;

  }

  EXPORT_SYMBOL_GPL(mcryptd_ahash_desc);

  
  void mcryptd_free_ahash(struct mcryptd_ahash *tfm)
  {
  	crypto_free_ahash(&tfm->base);
  }
  EXPORT_SYMBOL_GPL(mcryptd_free_ahash);

  static int __init mcryptd_init(void)
  {
  	int err, cpu;
  	struct mcryptd_flush_list *flist;
  
  	mcryptd_flist = alloc_percpu(struct mcryptd_flush_list);
  	for_each_possible_cpu(cpu) {
  		flist = per_cpu_ptr(mcryptd_flist, cpu);
  		INIT_LIST_HEAD(&flist->list);
  		mutex_init(&flist->lock);
  	}
  
  	err = mcryptd_init_queue(&mqueue, MCRYPTD_MAX_CPU_QLEN);
  	if (err) {
  		free_percpu(mcryptd_flist);
  		return err;
  	}
  
  	err = crypto_register_template(&mcryptd_tmpl);
  	if (err) {
  		mcryptd_fini_queue(&mqueue);
  		free_percpu(mcryptd_flist);
  	}
  
  	return err;
  }
  
  static void __exit mcryptd_exit(void)
  {
  	mcryptd_fini_queue(&mqueue);
  	crypto_unregister_template(&mcryptd_tmpl);
  	free_percpu(mcryptd_flist);
  }
  
  subsys_initcall(mcryptd_init);
  module_exit(mcryptd_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Software async multibuffer crypto daemon");

  MODULE_ALIAS_CRYPTO("mcryptd");