[PATCH] crypto: engine - support for parallel requests

[PATCH] crypto: engine - support for parallel requests

[Iuliana Prodan]

Added support for executing multiple requests, in parallel,
for crypto engine.
A new callback is added, can_enqueue_hardware, which asks the
driver if the hardware has free space, to enqueue a new request.
The new crypto_engine_alloc_init_and_set function, initialize
crypto-engine, sets the maximum size for crypto-engine software
queue (not hardcoded anymore) and the can_enqueue_hardware callback.
On crypto_pump_requests, if can_enqueue_hardware callback returns true,
a new request is send to hardware, until there is no space and the
callback returns false.

Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>

---
Changes since V0 (RFC):
	- removed max_no_req and no_req, as the number of request that
	  can be processed in parallel;
	- added a new callback, can_enqueue_hardware, to check whether
	  the hardware can process a new request. 
---

 crypto/crypto_engine.c  | 105 ++++++++++++++++++++++++++++++------------------
 include/crypto/engine.h |  10 +++--
 2 files changed, 71 insertions(+), 44 deletions(-)

diff --git a/crypto/crypto_engine.c b/crypto/crypto_engine.c
index eb029ff..ee3a610 100644
--- a/crypto/crypto_engine.c
+++ b/crypto/crypto_engine.c
@@ -22,32 +22,18 @@
  * @err: error number
  */
 static void crypto_finalize_request(struct crypto_engine *engine,
-			     struct crypto_async_request *req, int err)
+				    struct crypto_async_request *req, int err)
 {
-	unsigned long flags;
-	bool finalize_cur_req = false;
 	int ret;
 	struct crypto_engine_ctx *enginectx;
 
-	spin_lock_irqsave(&engine->queue_lock, flags);
-	if (engine->cur_req == req)
-		finalize_cur_req = true;
-	spin_unlock_irqrestore(&engine->queue_lock, flags);
-
-	if (finalize_cur_req) {
-		enginectx = crypto_tfm_ctx(req->tfm);
-		if (engine->cur_req_prepared &&
-		    enginectx->op.unprepare_request) {
-			ret = enginectx->op.unprepare_request(engine, req);
-			if (ret)
-				dev_err(engine->dev, "failed to unprepare request\n");
-		}
-		spin_lock_irqsave(&engine->queue_lock, flags);
-		engine->cur_req = NULL;
-		engine->cur_req_prepared = false;
-		spin_unlock_irqrestore(&engine->queue_lock, flags);
+	enginectx = crypto_tfm_ctx(req->tfm);
+	if (enginectx->op.prepare_request &&
+	    enginectx->op.unprepare_request) {
+		ret = enginectx->op.unprepare_request(engine, req);
+		if (ret)
+			dev_err(engine->dev, "failed to unprepare request\n");
 	}
-
 	req->complete(req, err);
 
 	kthread_queue_work(engine->kworker, &engine->pump_requests);
@@ -73,10 +59,6 @@ static void crypto_pump_requests(struct crypto_engine *engine,
 
 	spin_lock_irqsave(&engine->queue_lock, flags);
 
-	/* Make sure we are not already running a request */
-	if (engine->cur_req)
-		goto out;
-
 	/* If another context is idling then defer */
 	if (engine->idling) {
 		kthread_queue_work(engine->kworker, &engine->pump_requests);
@@ -108,13 +90,18 @@ static void crypto_pump_requests(struct crypto_engine *engine,
 		goto out;
 	}
 
+start_request:
+	/* If hw is busy, do not send any request */
+	if (engine->can_enqueue_hardware &&
+	    !engine->can_enqueue_hardware(engine->dev))
+		goto out;
+
 	/* Get the fist request from the engine queue to handle */
 	backlog = crypto_get_backlog(&engine->queue);
 	async_req = crypto_dequeue_request(&engine->queue);
 	if (!async_req)
 		goto out;
 
-	engine->cur_req = async_req;
 	if (backlog)
 		backlog->complete(backlog, -EINPROGRESS);
 
@@ -130,7 +117,7 @@ static void crypto_pump_requests(struct crypto_engine *engine,
 		ret = engine->prepare_crypt_hardware(engine);
 		if (ret) {
 			dev_err(engine->dev, "failed to prepare crypt hardware\n");
-			goto req_err;
+			goto req_err_2;
 		}
 	}
 
@@ -141,26 +128,38 @@ static void crypto_pump_requests(struct crypto_engine *engine,
 		if (ret) {
 			dev_err(engine->dev, "failed to prepare request: %d\n",
 				ret);
-			goto req_err;
+			goto req_err_2;
 		}
-		engine->cur_req_prepared = true;
 	}
 	if (!enginectx->op.do_one_request) {
 		dev_err(engine->dev, "failed to do request\n");
 		ret = -EINVAL;
-		goto req_err;
+		goto req_err_1;
 	}
+
 	ret = enginectx->op.do_one_request(engine, async_req);
 	if (ret) {
 		dev_err(engine->dev, "Failed to do one request from queue: %d\n", ret);
-		goto req_err;
+		goto req_err_1;
 	}
-	return;
 
-req_err:
-	crypto_finalize_request(engine, async_req, ret);
-	return;
+	goto retry;
+
+req_err_1:
+	if (enginectx->op.unprepare_request) {
+		ret = enginectx->op.unprepare_request(engine, async_req);
+		if (ret)
+			dev_err(engine->dev, "failed to unprepare request\n");
+	}
+req_err_2:
+	async_req->complete(async_req, ret);
 
+retry:
+	if (engine->can_enqueue_hardware) {
+		spin_lock_irqsave(&engine->queue_lock, flags);
+		goto start_request;
+	}
+	return;
 out:
 	spin_unlock_irqrestore(&engine->queue_lock, flags);
 }
@@ -386,15 +385,25 @@ int crypto_engine_stop(struct crypto_engine *engine)
 EXPORT_SYMBOL_GPL(crypto_engine_stop);
 
 /**
- * crypto_engine_alloc_init - allocate crypto hardware engine structure and
- * initialize it.
+ * crypto_engine_alloc_init_and_set - allocate crypto hardware engine structure
+ * and initialize it by setting the maximum number of entries in the software
+ * crypto-engine queue.
  * @dev: the device attached with one hardware engine
+ * @cbk: pointer to a callback function to be invoked when pumping requests
+ *       to check whether the hardware can process a new request.
+ *       This has the form:
+ *       callback(struct device *dev)
+ *       where:
+ *       @dev: contains the device that processed this response.
  * @rt: whether this queue is set to run as a realtime task
+ * @qlen: maximum size of the crypto-engine queue
  *
  * This must be called from context that can sleep.
  * Return: the crypto engine structure on success, else NULL.
  */
-struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
+struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
+						       bool (*cbk)(struct device *dev),
+						       bool rt, int qlen)
 {
 	struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
 	struct crypto_engine *engine;
@@ -411,12 +420,12 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
 	engine->running = false;
 	engine->busy = false;
 	engine->idling = false;
-	engine->cur_req_prepared = false;
 	engine->priv_data = dev;
+	engine->can_enqueue_hardware = cbk;
 	snprintf(engine->name, sizeof(engine->name),
 		 "%s-engine", dev_name(dev));
 
-	crypto_init_queue(&engine->queue, CRYPTO_ENGINE_MAX_QLEN);
+	crypto_init_queue(&engine->queue, qlen);
 	spin_lock_init(&engine->queue_lock);
 
 	engine->kworker = kthread_create_worker(0, "%s", engine->name);
@@ -433,6 +442,22 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
 
 	return engine;
 }
+EXPORT_SYMBOL_GPL(crypto_engine_alloc_init_and_set);
+
+/**
+ * crypto_engine_alloc_init - allocate crypto hardware engine structure and
+ * initialize it.
+ * @dev: the device attached with one hardware engine
+ * @rt: whether this queue is set to run as a realtime task
+ *
+ * This must be called from context that can sleep.
+ * Return: the crypto engine structure on success, else NULL.
+ */
+struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
+{
+	return crypto_engine_alloc_init_and_set(dev, NULL, rt,
+						CRYPTO_ENGINE_MAX_QLEN);
+}
 EXPORT_SYMBOL_GPL(crypto_engine_alloc_init);
 
 /**
diff --git a/include/crypto/engine.h b/include/crypto/engine.h
index e29cd67..15d1150 100644
--- a/include/crypto/engine.h
+++ b/include/crypto/engine.h
@@ -24,7 +24,6 @@
  * @idling: the engine is entering idle state
  * @busy: request pump is busy
  * @running: the engine is on working
- * @cur_req_prepared: current request is prepared
  * @list: link with the global crypto engine list
  * @queue_lock: spinlock to syncronise access to request queue
  * @queue: the crypto queue of the engine
@@ -35,17 +34,17 @@
  * @unprepare_crypt_hardware: there are currently no more requests on the
  * queue so the subsystem notifies the driver that it may relax the
  * hardware by issuing this call
+ * @can_enqueue_hardware: callback to check whether the hardware can process
+ * a new request
  * @kworker: kthread worker struct for request pump
  * @pump_requests: work struct for scheduling work to the request pump
  * @priv_data: the engine private data
- * @cur_req: the current request which is on processing
  */
 struct crypto_engine {
 	char			name[ENGINE_NAME_LEN];
 	bool			idling;
 	bool			busy;
 	bool			running;
-	bool			cur_req_prepared;
 
 	struct list_head	list;
 	spinlock_t		queue_lock;
@@ -56,12 +55,12 @@ struct crypto_engine {
 
 	int (*prepare_crypt_hardware)(struct crypto_engine *engine);
 	int (*unprepare_crypt_hardware)(struct crypto_engine *engine);
+	bool (*can_enqueue_hardware)(struct device *dev);
 
 	struct kthread_worker           *kworker;
 	struct kthread_work             pump_requests;
 
 	void				*priv_data;
-	struct crypto_async_request	*cur_req;
 };
 
 /*
@@ -102,6 +101,9 @@ void crypto_finalize_skcipher_request(struct crypto_engine *engine,
 int crypto_engine_start(struct crypto_engine *engine);
 int crypto_engine_stop(struct crypto_engine *engine);
 struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt);
+struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
+						       bool (*cbk)(struct device *dev),
+						       bool rt, int qlen);
 int crypto_engine_exit(struct crypto_engine *engine);
 
 #endif /* _CRYPTO_ENGINE_H */
-- 
2.1.0

Re: [PATCH] crypto: engine - support for parallel requests

[Corentin Labbe]

On Tue, Jan 28, 2020 at 12:17:05AM +0200, Iuliana Prodan wrote:
> Added support for executing multiple requests, in parallel,
> for crypto engine.
> A new callback is added, can_enqueue_hardware, which asks the
> driver if the hardware has free space, to enqueue a new request.
> The new crypto_engine_alloc_init_and_set function, initialize
> crypto-engine, sets the maximum size for crypto-engine software
> queue (not hardcoded anymore) and the can_enqueue_hardware callback.
> On crypto_pump_requests, if can_enqueue_hardware callback returns true,
> a new request is send to hardware, until there is no space and the
> callback returns false.
> 
> Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
> 
> ---
> Changes since V0 (RFC):
> 	- removed max_no_req and no_req, as the number of request that
> 	  can be processed in parallel;
> 	- added a new callback, can_enqueue_hardware, to check whether
> 	  the hardware can process a new request. 
> ---
> 
>  crypto/crypto_engine.c  | 105 ++++++++++++++++++++++++++++++------------------
>  include/crypto/engine.h |  10 +++--
>  2 files changed, 71 insertions(+), 44 deletions(-)
> 
> diff --git a/crypto/crypto_engine.c b/crypto/crypto_engine.c
> index eb029ff..ee3a610 100644
> --- a/crypto/crypto_engine.c
> +++ b/crypto/crypto_engine.c
> @@ -22,32 +22,18 @@
>   * @err: error number
>   */
>  static void crypto_finalize_request(struct crypto_engine *engine,
> -			     struct crypto_async_request *req, int err)
> +				    struct crypto_async_request *req, int err)
>  {
> -	unsigned long flags;
> -	bool finalize_cur_req = false;
>  	int ret;
>  	struct crypto_engine_ctx *enginectx;
>  
> -	spin_lock_irqsave(&engine->queue_lock, flags);
> -	if (engine->cur_req == req)
> -		finalize_cur_req = true;
> -	spin_unlock_irqrestore(&engine->queue_lock, flags);
> -
> -	if (finalize_cur_req) {
> -		enginectx = crypto_tfm_ctx(req->tfm);
> -		if (engine->cur_req_prepared &&
> -		    enginectx->op.unprepare_request) {
> -			ret = enginectx->op.unprepare_request(engine, req);
> -			if (ret)
> -				dev_err(engine->dev, "failed to unprepare request\n");
> -		}
> -		spin_lock_irqsave(&engine->queue_lock, flags);
> -		engine->cur_req = NULL;
> -		engine->cur_req_prepared = false;
> -		spin_unlock_irqrestore(&engine->queue_lock, flags);
> +	enginectx = crypto_tfm_ctx(req->tfm);
> +	if (enginectx->op.prepare_request &&
> +	    enginectx->op.unprepare_request) {
> +		ret = enginectx->op.unprepare_request(engine, req);
> +		if (ret)
> +			dev_err(engine->dev, "failed to unprepare request\n");
>  	}
> -
>  	req->complete(req, err);
>  
>  	kthread_queue_work(engine->kworker, &engine->pump_requests);
> @@ -73,10 +59,6 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>  
>  	spin_lock_irqsave(&engine->queue_lock, flags);
>  
> -	/* Make sure we are not already running a request */
> -	if (engine->cur_req)
> -		goto out;
> -
>  	/* If another context is idling then defer */
>  	if (engine->idling) {
>  		kthread_queue_work(engine->kworker, &engine->pump_requests);
> @@ -108,13 +90,18 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>  		goto out;
>  	}
>  
> +start_request:
> +	/* If hw is busy, do not send any request */
> +	if (engine->can_enqueue_hardware &&
> +	    !engine->can_enqueue_hardware(engine->dev))
> +		goto out;
> +
>  	/* Get the fist request from the engine queue to handle */
>  	backlog = crypto_get_backlog(&engine->queue);
>  	async_req = crypto_dequeue_request(&engine->queue);
>  	if (!async_req)
>  		goto out;
>  
> -	engine->cur_req = async_req;
>  	if (backlog)
>  		backlog->complete(backlog, -EINPROGRESS);
>  
> @@ -130,7 +117,7 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>  		ret = engine->prepare_crypt_hardware(engine);
>  		if (ret) {
>  			dev_err(engine->dev, "failed to prepare crypt hardware\n");
> -			goto req_err;
> +			goto req_err_2;
>  		}
>  	}
>  
> @@ -141,26 +128,38 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>  		if (ret) {
>  			dev_err(engine->dev, "failed to prepare request: %d\n",
>  				ret);
> -			goto req_err;
> +			goto req_err_2;
>  		}
> -		engine->cur_req_prepared = true;
>  	}
>  	if (!enginectx->op.do_one_request) {
>  		dev_err(engine->dev, "failed to do request\n");
>  		ret = -EINVAL;
> -		goto req_err;
> +		goto req_err_1;
>  	}
> +
>  	ret = enginectx->op.do_one_request(engine, async_req);
>  	if (ret) {
>  		dev_err(engine->dev, "Failed to do one request from queue: %d\n", ret);
> -		goto req_err;
> +		goto req_err_1;
>  	}
> -	return;
>  
> -req_err:
> -	crypto_finalize_request(engine, async_req, ret);
> -	return;
> +	goto retry;
> +
> +req_err_1:
> +	if (enginectx->op.unprepare_request) {
> +		ret = enginectx->op.unprepare_request(engine, async_req);
> +		if (ret)
> +			dev_err(engine->dev, "failed to unprepare request\n");
> +	}
> +req_err_2:
> +	async_req->complete(async_req, ret);
>  
> +retry:
> +	if (engine->can_enqueue_hardware) {
> +		spin_lock_irqsave(&engine->queue_lock, flags);
> +		goto start_request;
> +	}
> +	return;
>  out:
>  	spin_unlock_irqrestore(&engine->queue_lock, flags);
>  }
> @@ -386,15 +385,25 @@ int crypto_engine_stop(struct crypto_engine *engine)
>  EXPORT_SYMBOL_GPL(crypto_engine_stop);
>  
>  /**
> - * crypto_engine_alloc_init - allocate crypto hardware engine structure and
> - * initialize it.
> + * crypto_engine_alloc_init_and_set - allocate crypto hardware engine structure
> + * and initialize it by setting the maximum number of entries in the software
> + * crypto-engine queue.
>   * @dev: the device attached with one hardware engine
> + * @cbk: pointer to a callback function to be invoked when pumping requests
> + *       to check whether the hardware can process a new request.
> + *       This has the form:
> + *       callback(struct device *dev)
> + *       where:
> + *       @dev: contains the device that processed this response.
>   * @rt: whether this queue is set to run as a realtime task
> + * @qlen: maximum size of the crypto-engine queue
>   *
>   * This must be called from context that can sleep.
>   * Return: the crypto engine structure on success, else NULL.
>   */
> -struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
> +struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
> +						       bool (*cbk)(struct device *dev),
> +						       bool rt, int qlen)
>  {
>  	struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
>  	struct crypto_engine *engine;
> @@ -411,12 +420,12 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
>  	engine->running = false;
>  	engine->busy = false;
>  	engine->idling = false;
> -	engine->cur_req_prepared = false;
>  	engine->priv_data = dev;
> +	engine->can_enqueue_hardware = cbk;
>  	snprintf(engine->name, sizeof(engine->name),
>  		 "%s-engine", dev_name(dev));
>  
> -	crypto_init_queue(&engine->queue, CRYPTO_ENGINE_MAX_QLEN);
> +	crypto_init_queue(&engine->queue, qlen);
>  	spin_lock_init(&engine->queue_lock);
>  
>  	engine->kworker = kthread_create_worker(0, "%s", engine->name);
> @@ -433,6 +442,22 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
>  
>  	return engine;
>  }
> +EXPORT_SYMBOL_GPL(crypto_engine_alloc_init_and_set);
> +
> +/**
> + * crypto_engine_alloc_init - allocate crypto hardware engine structure and
> + * initialize it.
> + * @dev: the device attached with one hardware engine
> + * @rt: whether this queue is set to run as a realtime task
> + *
> + * This must be called from context that can sleep.
> + * Return: the crypto engine structure on success, else NULL.
> + */
> +struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
> +{
> +	return crypto_engine_alloc_init_and_set(dev, NULL, rt,
> +						CRYPTO_ENGINE_MAX_QLEN);
> +}
>  EXPORT_SYMBOL_GPL(crypto_engine_alloc_init);
>  
>  /**
> diff --git a/include/crypto/engine.h b/include/crypto/engine.h
> index e29cd67..15d1150 100644
> --- a/include/crypto/engine.h
> +++ b/include/crypto/engine.h
> @@ -24,7 +24,6 @@
>   * @idling: the engine is entering idle state
>   * @busy: request pump is busy
>   * @running: the engine is on working
> - * @cur_req_prepared: current request is prepared
>   * @list: link with the global crypto engine list
>   * @queue_lock: spinlock to syncronise access to request queue
>   * @queue: the crypto queue of the engine
> @@ -35,17 +34,17 @@
>   * @unprepare_crypt_hardware: there are currently no more requests on the
>   * queue so the subsystem notifies the driver that it may relax the
>   * hardware by issuing this call
> + * @can_enqueue_hardware: callback to check whether the hardware can process
> + * a new request
>   * @kworker: kthread worker struct for request pump
>   * @pump_requests: work struct for scheduling work to the request pump
>   * @priv_data: the engine private data
> - * @cur_req: the current request which is on processing
>   */
>  struct crypto_engine {
>  	char			name[ENGINE_NAME_LEN];
>  	bool			idling;
>  	bool			busy;
>  	bool			running;
> -	bool			cur_req_prepared;
>  
>  	struct list_head	list;
>  	spinlock_t		queue_lock;
> @@ -56,12 +55,12 @@ struct crypto_engine {
>  
>  	int (*prepare_crypt_hardware)(struct crypto_engine *engine);
>  	int (*unprepare_crypt_hardware)(struct crypto_engine *engine);
> +	bool (*can_enqueue_hardware)(struct device *dev);
>  
>  	struct kthread_worker           *kworker;
>  	struct kthread_work             pump_requests;
>  
>  	void				*priv_data;
> -	struct crypto_async_request	*cur_req;
>  };
>  
>  /*
> @@ -102,6 +101,9 @@ void crypto_finalize_skcipher_request(struct crypto_engine *engine,
>  int crypto_engine_start(struct crypto_engine *engine);
>  int crypto_engine_stop(struct crypto_engine *engine);
>  struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt);
> +struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
> +						       bool (*cbk)(struct device *dev),
> +						       bool rt, int qlen);
>  int crypto_engine_exit(struct crypto_engine *engine);
>  
>  #endif /* _CRYPTO_ENGINE_H */
> -- 
> 2.1.0
> 


Hello

For someone which said "I'm planning to improve crypto-engine incrementally", this is lot of change in one.
You could have used my first 4 patchs which clean crypto_engine (for getting rid of cur_req_prepared/cur_req for example).

Furthermore, the callback should not be registred at init, but should be part of the struct crypto_engine_op.
And the callback need to have the crypto engine itself as parameter, in case the driver own more than one crypto engine.
In my serie I added also the current request for giving more hint on the current state and let the driver do the right decision.

Regards

Re: [PATCH] crypto: engine - support for parallel requests

[Iuliana Prodan]

On 1/28/2020 10:58 AM, Corentin Labbe wrote:
> On Tue, Jan 28, 2020 at 12:17:05AM +0200, Iuliana Prodan wrote:
>> Added support for executing multiple requests, in parallel,
>> for crypto engine.
>> A new callback is added, can_enqueue_hardware, which asks the
>> driver if the hardware has free space, to enqueue a new request.
>> The new crypto_engine_alloc_init_and_set function, initialize
>> crypto-engine, sets the maximum size for crypto-engine software
>> queue (not hardcoded anymore) and the can_enqueue_hardware callback.
>> On crypto_pump_requests, if can_enqueue_hardware callback returns true,
>> a new request is send to hardware, until there is no space and the
>> callback returns false.
>>
>> Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
>>
>> ---
>> Changes since V0 (RFC):
>> 	- removed max_no_req and no_req, as the number of request that
>> 	  can be processed in parallel;
>> 	- added a new callback, can_enqueue_hardware, to check whether
>> 	  the hardware can process a new request.
>> ---
>>
>>   crypto/crypto_engine.c  | 105 ++++++++++++++++++++++++++++++------------------
>>   include/crypto/engine.h |  10 +++--
>>   2 files changed, 71 insertions(+), 44 deletions(-)
>>
>> diff --git a/crypto/crypto_engine.c b/crypto/crypto_engine.c
>> index eb029ff..ee3a610 100644
>> --- a/crypto/crypto_engine.c
>> +++ b/crypto/crypto_engine.c
>> @@ -22,32 +22,18 @@
>>    * @err: error number
>>    */
>>   static void crypto_finalize_request(struct crypto_engine *engine,
>> -			     struct crypto_async_request *req, int err)
>> +				    struct crypto_async_request *req, int err)
>>   {
>> -	unsigned long flags;
>> -	bool finalize_cur_req = false;
>>   	int ret;
>>   	struct crypto_engine_ctx *enginectx;
>>   
>> -	spin_lock_irqsave(&engine->queue_lock, flags);
>> -	if (engine->cur_req == req)
>> -		finalize_cur_req = true;
>> -	spin_unlock_irqrestore(&engine->queue_lock, flags);
>> -
>> -	if (finalize_cur_req) {
>> -		enginectx = crypto_tfm_ctx(req->tfm);
>> -		if (engine->cur_req_prepared &&
>> -		    enginectx->op.unprepare_request) {
>> -			ret = enginectx->op.unprepare_request(engine, req);
>> -			if (ret)
>> -				dev_err(engine->dev, "failed to unprepare request\n");
>> -		}
>> -		spin_lock_irqsave(&engine->queue_lock, flags);
>> -		engine->cur_req = NULL;
>> -		engine->cur_req_prepared = false;
>> -		spin_unlock_irqrestore(&engine->queue_lock, flags);
>> +	enginectx = crypto_tfm_ctx(req->tfm);
>> +	if (enginectx->op.prepare_request &&
>> +	    enginectx->op.unprepare_request) {
>> +		ret = enginectx->op.unprepare_request(engine, req);
>> +		if (ret)
>> +			dev_err(engine->dev, "failed to unprepare request\n");
>>   	}
>> -
>>   	req->complete(req, err);
>>   
>>   	kthread_queue_work(engine->kworker, &engine->pump_requests);
>> @@ -73,10 +59,6 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>>   
>>   	spin_lock_irqsave(&engine->queue_lock, flags);
>>   
>> -	/* Make sure we are not already running a request */
>> -	if (engine->cur_req)
>> -		goto out;
>> -
>>   	/* If another context is idling then defer */
>>   	if (engine->idling) {
>>   		kthread_queue_work(engine->kworker, &engine->pump_requests);
>> @@ -108,13 +90,18 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>>   		goto out;
>>   	}
>>   
>> +start_request:
>> +	/* If hw is busy, do not send any request */
>> +	if (engine->can_enqueue_hardware &&
>> +	    !engine->can_enqueue_hardware(engine->dev))
>> +		goto out;
>> +
>>   	/* Get the fist request from the engine queue to handle */
>>   	backlog = crypto_get_backlog(&engine->queue);
>>   	async_req = crypto_dequeue_request(&engine->queue);
>>   	if (!async_req)
>>   		goto out;
>>   
>> -	engine->cur_req = async_req;
>>   	if (backlog)
>>   		backlog->complete(backlog, -EINPROGRESS);
>>   
>> @@ -130,7 +117,7 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>>   		ret = engine->prepare_crypt_hardware(engine);
>>   		if (ret) {
>>   			dev_err(engine->dev, "failed to prepare crypt hardware\n");
>> -			goto req_err;
>> +			goto req_err_2;
>>   		}
>>   	}
>>   
>> @@ -141,26 +128,38 @@ static void crypto_pump_requests(struct crypto_engine *engine,
>>   		if (ret) {
>>   			dev_err(engine->dev, "failed to prepare request: %d\n",
>>   				ret);
>> -			goto req_err;
>> +			goto req_err_2;
>>   		}
>> -		engine->cur_req_prepared = true;
>>   	}
>>   	if (!enginectx->op.do_one_request) {
>>   		dev_err(engine->dev, "failed to do request\n");
>>   		ret = -EINVAL;
>> -		goto req_err;
>> +		goto req_err_1;
>>   	}
>> +
>>   	ret = enginectx->op.do_one_request(engine, async_req);
>>   	if (ret) {
>>   		dev_err(engine->dev, "Failed to do one request from queue: %d\n", ret);
>> -		goto req_err;
>> +		goto req_err_1;
>>   	}
>> -	return;
>>   
>> -req_err:
>> -	crypto_finalize_request(engine, async_req, ret);
>> -	return;
>> +	goto retry;
>> +
>> +req_err_1:
>> +	if (enginectx->op.unprepare_request) {
>> +		ret = enginectx->op.unprepare_request(engine, async_req);
>> +		if (ret)
>> +			dev_err(engine->dev, "failed to unprepare request\n");
>> +	}
>> +req_err_2:
>> +	async_req->complete(async_req, ret);
>>   
>> +retry:
>> +	if (engine->can_enqueue_hardware) {
>> +		spin_lock_irqsave(&engine->queue_lock, flags);
>> +		goto start_request;
>> +	}
>> +	return;
>>   out:
>>   	spin_unlock_irqrestore(&engine->queue_lock, flags);
>>   }
>> @@ -386,15 +385,25 @@ int crypto_engine_stop(struct crypto_engine *engine)
>>   EXPORT_SYMBOL_GPL(crypto_engine_stop);
>>   
>>   /**
>> - * crypto_engine_alloc_init - allocate crypto hardware engine structure and
>> - * initialize it.
>> + * crypto_engine_alloc_init_and_set - allocate crypto hardware engine structure
>> + * and initialize it by setting the maximum number of entries in the software
>> + * crypto-engine queue.
>>    * @dev: the device attached with one hardware engine
>> + * @cbk: pointer to a callback function to be invoked when pumping requests
>> + *       to check whether the hardware can process a new request.
>> + *       This has the form:
>> + *       callback(struct device *dev)
>> + *       where:
>> + *       @dev: contains the device that processed this response.
>>    * @rt: whether this queue is set to run as a realtime task
>> + * @qlen: maximum size of the crypto-engine queue
>>    *
>>    * This must be called from context that can sleep.
>>    * Return: the crypto engine structure on success, else NULL.
>>    */
>> -struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
>> +struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
>> +						       bool (*cbk)(struct device *dev),
>> +						       bool rt, int qlen)
>>   {
>>   	struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
>>   	struct crypto_engine *engine;
>> @@ -411,12 +420,12 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
>>   	engine->running = false;
>>   	engine->busy = false;
>>   	engine->idling = false;
>> -	engine->cur_req_prepared = false;
>>   	engine->priv_data = dev;
>> +	engine->can_enqueue_hardware = cbk;
>>   	snprintf(engine->name, sizeof(engine->name),
>>   		 "%s-engine", dev_name(dev));
>>   
>> -	crypto_init_queue(&engine->queue, CRYPTO_ENGINE_MAX_QLEN);
>> +	crypto_init_queue(&engine->queue, qlen);
>>   	spin_lock_init(&engine->queue_lock);
>>   
>>   	engine->kworker = kthread_create_worker(0, "%s", engine->name);
>> @@ -433,6 +442,22 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
>>   
>>   	return engine;
>>   }
>> +EXPORT_SYMBOL_GPL(crypto_engine_alloc_init_and_set);
>> +
>> +/**
>> + * crypto_engine_alloc_init - allocate crypto hardware engine structure and
>> + * initialize it.
>> + * @dev: the device attached with one hardware engine
>> + * @rt: whether this queue is set to run as a realtime task
>> + *
>> + * This must be called from context that can sleep.
>> + * Return: the crypto engine structure on success, else NULL.
>> + */
>> +struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
>> +{
>> +	return crypto_engine_alloc_init_and_set(dev, NULL, rt,
>> +						CRYPTO_ENGINE_MAX_QLEN);
>> +}
>>   EXPORT_SYMBOL_GPL(crypto_engine_alloc_init);
>>   
>>   /**
>> diff --git a/include/crypto/engine.h b/include/crypto/engine.h
>> index e29cd67..15d1150 100644
>> --- a/include/crypto/engine.h
>> +++ b/include/crypto/engine.h
>> @@ -24,7 +24,6 @@
>>    * @idling: the engine is entering idle state
>>    * @busy: request pump is busy
>>    * @running: the engine is on working
>> - * @cur_req_prepared: current request is prepared
>>    * @list: link with the global crypto engine list
>>    * @queue_lock: spinlock to syncronise access to request queue
>>    * @queue: the crypto queue of the engine
>> @@ -35,17 +34,17 @@
>>    * @unprepare_crypt_hardware: there are currently no more requests on the
>>    * queue so the subsystem notifies the driver that it may relax the
>>    * hardware by issuing this call
>> + * @can_enqueue_hardware: callback to check whether the hardware can process
>> + * a new request
>>    * @kworker: kthread worker struct for request pump
>>    * @pump_requests: work struct for scheduling work to the request pump
>>    * @priv_data: the engine private data
>> - * @cur_req: the current request which is on processing
>>    */
>>   struct crypto_engine {
>>   	char			name[ENGINE_NAME_LEN];
>>   	bool			idling;
>>   	bool			busy;
>>   	bool			running;
>> -	bool			cur_req_prepared;
>>   
>>   	struct list_head	list;
>>   	spinlock_t		queue_lock;
>> @@ -56,12 +55,12 @@ struct crypto_engine {
>>   
>>   	int (*prepare_crypt_hardware)(struct crypto_engine *engine);
>>   	int (*unprepare_crypt_hardware)(struct crypto_engine *engine);
>> +	bool (*can_enqueue_hardware)(struct device *dev);
>>   
>>   	struct kthread_worker           *kworker;
>>   	struct kthread_work             pump_requests;
>>   
>>   	void				*priv_data;
>> -	struct crypto_async_request	*cur_req;
>>   };
>>   
>>   /*
>> @@ -102,6 +101,9 @@ void crypto_finalize_skcipher_request(struct crypto_engine *engine,
>>   int crypto_engine_start(struct crypto_engine *engine);
>>   int crypto_engine_stop(struct crypto_engine *engine);
>>   struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt);
>> +struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
>> +						       bool (*cbk)(struct device *dev),
>> +						       bool rt, int qlen);
>>   int crypto_engine_exit(struct crypto_engine *engine);
>>   
>>   #endif /* _CRYPTO_ENGINE_H */
>> -- 
>> 2.1.0
>>
> 
> 
> Hello
> 
> For someone which said "I'm planning to improve crypto-engine incrementally", this is lot of change in one.
> You could have used my first 4 patchs which clean crypto_engine (for getting rid of cur_req_prepared/cur_req for example).
> 

The number of patches is something debatable!
Your first patches were already in my RFC!
This patch adds support for independent requests by adding a check for 
hardware availability. Removing current request (cur_req) means we need 
to add something else to break from the loop we have in pump_requests(). 
I didn't see how I could split it in several commits, but I don't see 
this as a big deal.
We can split it any way we/Herbert agree on.

> Furthermore, the callback should not be registred at init, but should be part of the struct crypto_engine_op.

We need to check if we can enqueue a new request before dequeuing the 
request from crypto-engine's queue.

> And the callback need to have the crypto engine itself as parameter, in case the driver own more than one crypto engine.
I can add crypto-engine as argument if you consider it useful.

> In my serie I added also the current request for giving more hint on the current state and let the driver do the right decision.
> 
If you refer to linked requests, this is something specific for your 
case/driver. I'm not handling this case, here.
But, for sure, is not correct to do do_one_request, only on the first 
request. This breaks the current API and doesn't scale to supporting 
multiple independent requests.

Re: [PATCH] crypto: engine - support for parallel requests

[Corentin Labbe]

On Tue, Jan 28, 2020 at 11:01:13AM +0000, Iuliana Prodan wrote:
> On 1/28/2020 10:58 AM, Corentin Labbe wrote:
> > On Tue, Jan 28, 2020 at 12:17:05AM +0200, Iuliana Prodan wrote:
> >> Added support for executing multiple requests, in parallel,
> >> for crypto engine.
> >> A new callback is added, can_enqueue_hardware, which asks the
> >> driver if the hardware has free space, to enqueue a new request.
> >> The new crypto_engine_alloc_init_and_set function, initialize
> >> crypto-engine, sets the maximum size for crypto-engine software
> >> queue (not hardcoded anymore) and the can_enqueue_hardware callback.
> >> On crypto_pump_requests, if can_enqueue_hardware callback returns true,
> >> a new request is send to hardware, until there is no space and the
> >> callback returns false.
> >>
> >> Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
> >>
> >> ---
> >> Changes since V0 (RFC):
> >> 	- removed max_no_req and no_req, as the number of request that
> >> 	  can be processed in parallel;
> >> 	- added a new callback, can_enqueue_hardware, to check whether
> >> 	  the hardware can process a new request.
> >> ---
> >>
> >>   crypto/crypto_engine.c  | 105 ++++++++++++++++++++++++++++++------------------
> >>   include/crypto/engine.h |  10 +++--
> >>   2 files changed, 71 insertions(+), 44 deletions(-)
> >>
> >> diff --git a/crypto/crypto_engine.c b/crypto/crypto_engine.c
> >> index eb029ff..ee3a610 100644
> >> --- a/crypto/crypto_engine.c
> >> +++ b/crypto/crypto_engine.c
> >> @@ -22,32 +22,18 @@
> >>    * @err: error number
> >>    */
> >>   static void crypto_finalize_request(struct crypto_engine *engine,
> >> -			     struct crypto_async_request *req, int err)
> >> +				    struct crypto_async_request *req, int err)
> >>   {
> >> -	unsigned long flags;
> >> -	bool finalize_cur_req = false;
> >>   	int ret;
> >>   	struct crypto_engine_ctx *enginectx;
> >>   
> >> -	spin_lock_irqsave(&engine->queue_lock, flags);
> >> -	if (engine->cur_req == req)
> >> -		finalize_cur_req = true;
> >> -	spin_unlock_irqrestore(&engine->queue_lock, flags);
> >> -
> >> -	if (finalize_cur_req) {
> >> -		enginectx = crypto_tfm_ctx(req->tfm);
> >> -		if (engine->cur_req_prepared &&
> >> -		    enginectx->op.unprepare_request) {
> >> -			ret = enginectx->op.unprepare_request(engine, req);
> >> -			if (ret)
> >> -				dev_err(engine->dev, "failed to unprepare request\n");
> >> -		}
> >> -		spin_lock_irqsave(&engine->queue_lock, flags);
> >> -		engine->cur_req = NULL;
> >> -		engine->cur_req_prepared = false;
> >> -		spin_unlock_irqrestore(&engine->queue_lock, flags);
> >> +	enginectx = crypto_tfm_ctx(req->tfm);
> >> +	if (enginectx->op.prepare_request &&
> >> +	    enginectx->op.unprepare_request) {
> >> +		ret = enginectx->op.unprepare_request(engine, req);
> >> +		if (ret)
> >> +			dev_err(engine->dev, "failed to unprepare request\n");
> >>   	}
> >> -
> >>   	req->complete(req, err);
> >>   
> >>   	kthread_queue_work(engine->kworker, &engine->pump_requests);
> >> @@ -73,10 +59,6 @@ static void crypto_pump_requests(struct crypto_engine *engine,
> >>   
> >>   	spin_lock_irqsave(&engine->queue_lock, flags);
> >>   
> >> -	/* Make sure we are not already running a request */
> >> -	if (engine->cur_req)
> >> -		goto out;
> >> -
> >>   	/* If another context is idling then defer */
> >>   	if (engine->idling) {
> >>   		kthread_queue_work(engine->kworker, &engine->pump_requests);
> >> @@ -108,13 +90,18 @@ static void crypto_pump_requests(struct crypto_engine *engine,
> >>   		goto out;
> >>   	}
> >>   
> >> +start_request:
> >> +	/* If hw is busy, do not send any request */
> >> +	if (engine->can_enqueue_hardware &&
> >> +	    !engine->can_enqueue_hardware(engine->dev))
> >> +		goto out;
> >> +
> >>   	/* Get the fist request from the engine queue to handle */
> >>   	backlog = crypto_get_backlog(&engine->queue);
> >>   	async_req = crypto_dequeue_request(&engine->queue);
> >>   	if (!async_req)
> >>   		goto out;
> >>   
> >> -	engine->cur_req = async_req;
> >>   	if (backlog)
> >>   		backlog->complete(backlog, -EINPROGRESS);
> >>   
> >> @@ -130,7 +117,7 @@ static void crypto_pump_requests(struct crypto_engine *engine,
> >>   		ret = engine->prepare_crypt_hardware(engine);
> >>   		if (ret) {
> >>   			dev_err(engine->dev, "failed to prepare crypt hardware\n");
> >> -			goto req_err;
> >> +			goto req_err_2;
> >>   		}
> >>   	}
> >>   
> >> @@ -141,26 +128,38 @@ static void crypto_pump_requests(struct crypto_engine *engine,
> >>   		if (ret) {
> >>   			dev_err(engine->dev, "failed to prepare request: %d\n",
> >>   				ret);
> >> -			goto req_err;
> >> +			goto req_err_2;
> >>   		}
> >> -		engine->cur_req_prepared = true;
> >>   	}
> >>   	if (!enginectx->op.do_one_request) {
> >>   		dev_err(engine->dev, "failed to do request\n");
> >>   		ret = -EINVAL;
> >> -		goto req_err;
> >> +		goto req_err_1;
> >>   	}
> >> +
> >>   	ret = enginectx->op.do_one_request(engine, async_req);
> >>   	if (ret) {
> >>   		dev_err(engine->dev, "Failed to do one request from queue: %d\n", ret);
> >> -		goto req_err;
> >> +		goto req_err_1;
> >>   	}
> >> -	return;
> >>   
> >> -req_err:
> >> -	crypto_finalize_request(engine, async_req, ret);
> >> -	return;
> >> +	goto retry;
> >> +
> >> +req_err_1:
> >> +	if (enginectx->op.unprepare_request) {
> >> +		ret = enginectx->op.unprepare_request(engine, async_req);
> >> +		if (ret)
> >> +			dev_err(engine->dev, "failed to unprepare request\n");
> >> +	}
> >> +req_err_2:
> >> +	async_req->complete(async_req, ret);
> >>   
> >> +retry:
> >> +	if (engine->can_enqueue_hardware) {
> >> +		spin_lock_irqsave(&engine->queue_lock, flags);
> >> +		goto start_request;
> >> +	}
> >> +	return;
> >>   out:
> >>   	spin_unlock_irqrestore(&engine->queue_lock, flags);
> >>   }
> >> @@ -386,15 +385,25 @@ int crypto_engine_stop(struct crypto_engine *engine)
> >>   EXPORT_SYMBOL_GPL(crypto_engine_stop);
> >>   
> >>   /**
> >> - * crypto_engine_alloc_init - allocate crypto hardware engine structure and
> >> - * initialize it.
> >> + * crypto_engine_alloc_init_and_set - allocate crypto hardware engine structure
> >> + * and initialize it by setting the maximum number of entries in the software
> >> + * crypto-engine queue.
> >>    * @dev: the device attached with one hardware engine
> >> + * @cbk: pointer to a callback function to be invoked when pumping requests
> >> + *       to check whether the hardware can process a new request.
> >> + *       This has the form:
> >> + *       callback(struct device *dev)
> >> + *       where:
> >> + *       @dev: contains the device that processed this response.
> >>    * @rt: whether this queue is set to run as a realtime task
> >> + * @qlen: maximum size of the crypto-engine queue
> >>    *
> >>    * This must be called from context that can sleep.
> >>    * Return: the crypto engine structure on success, else NULL.
> >>    */
> >> -struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
> >> +struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
> >> +						       bool (*cbk)(struct device *dev),
> >> +						       bool rt, int qlen)
> >>   {
> >>   	struct sched_param param = { .sched_priority = MAX_RT_PRIO / 2 };
> >>   	struct crypto_engine *engine;
> >> @@ -411,12 +420,12 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
> >>   	engine->running = false;
> >>   	engine->busy = false;
> >>   	engine->idling = false;
> >> -	engine->cur_req_prepared = false;
> >>   	engine->priv_data = dev;
> >> +	engine->can_enqueue_hardware = cbk;
> >>   	snprintf(engine->name, sizeof(engine->name),
> >>   		 "%s-engine", dev_name(dev));
> >>   
> >> -	crypto_init_queue(&engine->queue, CRYPTO_ENGINE_MAX_QLEN);
> >> +	crypto_init_queue(&engine->queue, qlen);
> >>   	spin_lock_init(&engine->queue_lock);
> >>   
> >>   	engine->kworker = kthread_create_worker(0, "%s", engine->name);
> >> @@ -433,6 +442,22 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
> >>   
> >>   	return engine;
> >>   }
> >> +EXPORT_SYMBOL_GPL(crypto_engine_alloc_init_and_set);
> >> +
> >> +/**
> >> + * crypto_engine_alloc_init - allocate crypto hardware engine structure and
> >> + * initialize it.
> >> + * @dev: the device attached with one hardware engine
> >> + * @rt: whether this queue is set to run as a realtime task
> >> + *
> >> + * This must be called from context that can sleep.
> >> + * Return: the crypto engine structure on success, else NULL.
> >> + */
> >> +struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
> >> +{
> >> +	return crypto_engine_alloc_init_and_set(dev, NULL, rt,
> >> +						CRYPTO_ENGINE_MAX_QLEN);
> >> +}
> >>   EXPORT_SYMBOL_GPL(crypto_engine_alloc_init);
> >>   
> >>   /**
> >> diff --git a/include/crypto/engine.h b/include/crypto/engine.h
> >> index e29cd67..15d1150 100644
> >> --- a/include/crypto/engine.h
> >> +++ b/include/crypto/engine.h
> >> @@ -24,7 +24,6 @@
> >>    * @idling: the engine is entering idle state
> >>    * @busy: request pump is busy
> >>    * @running: the engine is on working
> >> - * @cur_req_prepared: current request is prepared
> >>    * @list: link with the global crypto engine list
> >>    * @queue_lock: spinlock to syncronise access to request queue
> >>    * @queue: the crypto queue of the engine
> >> @@ -35,17 +34,17 @@
> >>    * @unprepare_crypt_hardware: there are currently no more requests on the
> >>    * queue so the subsystem notifies the driver that it may relax the
> >>    * hardware by issuing this call
> >> + * @can_enqueue_hardware: callback to check whether the hardware can process
> >> + * a new request
> >>    * @kworker: kthread worker struct for request pump
> >>    * @pump_requests: work struct for scheduling work to the request pump
> >>    * @priv_data: the engine private data
> >> - * @cur_req: the current request which is on processing
> >>    */
> >>   struct crypto_engine {
> >>   	char			name[ENGINE_NAME_LEN];
> >>   	bool			idling;
> >>   	bool			busy;
> >>   	bool			running;
> >> -	bool			cur_req_prepared;
> >>   
> >>   	struct list_head	list;
> >>   	spinlock_t		queue_lock;
> >> @@ -56,12 +55,12 @@ struct crypto_engine {
> >>   
> >>   	int (*prepare_crypt_hardware)(struct crypto_engine *engine);
> >>   	int (*unprepare_crypt_hardware)(struct crypto_engine *engine);
> >> +	bool (*can_enqueue_hardware)(struct device *dev);
> >>   
> >>   	struct kthread_worker           *kworker;
> >>   	struct kthread_work             pump_requests;
> >>   
> >>   	void				*priv_data;
> >> -	struct crypto_async_request	*cur_req;
> >>   };
> >>   
> >>   /*
> >> @@ -102,6 +101,9 @@ void crypto_finalize_skcipher_request(struct crypto_engine *engine,
> >>   int crypto_engine_start(struct crypto_engine *engine);
> >>   int crypto_engine_stop(struct crypto_engine *engine);
> >>   struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt);
> >> +struct crypto_engine *crypto_engine_alloc_init_and_set(struct device *dev,
> >> +						       bool (*cbk)(struct device *dev),
> >> +						       bool rt, int qlen);
> >>   int crypto_engine_exit(struct crypto_engine *engine);
> >>   
> >>   #endif /* _CRYPTO_ENGINE_H */
> >> -- 
> >> 2.1.0
> >>
> > 
> > 
> > Hello
> > 
> > For someone which said "I'm planning to improve crypto-engine incrementally", this is lot of change in one.
> > You could have used my first 4 patchs which clean crypto_engine (for getting rid of cur_req_prepared/cur_req for example).
> > 
> 
> The number of patches is something debatable!
> Your first patches were already in my RFC!
> This patch adds support for independent requests by adding a check for 
> hardware availability. Removing current request (cur_req) means we need 
> to add something else to break from the loop we have in pump_requests(). 
> I didn't see how I could split it in several commits, but I don't see 
> this as a big deal.
> We can split it any way we/Herbert agree on.
> 
> > Furthermore, the callback should not be registred at init, but should be part of the struct crypto_engine_op.
> 
> We need to check if we can enqueue a new request before dequeuing the 
> request from crypto-engine's queue.
> 
> > And the callback need to have the crypto engine itself as parameter, in case the driver own more than one crypto engine.
> I can add crypto-engine as argument if you consider it useful.
> 
> > In my serie I added also the current request for giving more hint on the current state and let the driver do the right decision.
> > 
> If you refer to linked requests, this is something specific for your 
> case/driver. I'm not handling this case, here.

That's the point, while I am trying to bring the change to support every case, you continue other each iteration to support only yours.

So I will stop here and wait to see what Herbert will think.

Regards