[PATCH] crypto: engine - support for parallel requests

From: Iuliana Prodan
Date: Mon Jan 27 2020 - 17:17:29 EST


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