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

From: Corentin Labbe
Date: Tue Jan 28 2020 - 03:58:54 EST


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@xxxxxxx>
>
> ---
> 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