linux-kernel - [PATCH 1/9] crypto: engine: workqueue can only be processed one by one

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Date:   Wed, 22 Jan 2020 11:45:20 +0100
From:   Corentin Labbe <clabbe.montjoie@...il.com>
To:     davem@...emloft.net, herbert@...dor.apana.org.au,
        mripard@...nel.org, wens@...e.org, iuliana.prodan@....com
Cc:     linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com,
        Corentin Labbe <clabbe.montjoie@...il.com>
Subject: [PATCH 1/9] crypto: engine: workqueue can only be processed one by one

Some bykeshedding are unnecessary since a workqueue can only be executed
one by one.
This behaviour is documented in:
- kernel/kthread.c: comment of kthread_worker_fn()
- Documentation/core-api/workqueue.rst: the functions associated with the work items one after the other

Signed-off-by: Corentin Labbe <clabbe.montjoie@...il.com>
---
 crypto/crypto_engine.c  | 13 -------------
 include/crypto/engine.h |  2 --
 2 files changed, 15 deletions(-)

diff --git a/crypto/crypto_engine.c b/crypto/crypto_engine.c
index eb029ff1e05a..feb0d82dd454 100644
--- a/crypto/crypto_engine.c
+++ b/crypto/crypto_engine.c
@@ -73,16 +73,6 @@ 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);
-		goto out;
-	}
-
 	/* Check if the engine queue is idle */
 	if (!crypto_queue_len(&engine->queue) || !engine->running) {
 		if (!engine->busy)
@@ -96,7 +86,6 @@ static void crypto_pump_requests(struct crypto_engine *engine,
 		}
 
 		engine->busy = false;
-		engine->idling = true;
 		spin_unlock_irqrestore(&engine->queue_lock, flags);
 
 		if (engine->unprepare_crypt_hardware &&
@@ -104,7 +93,6 @@ static void crypto_pump_requests(struct crypto_engine *engine,
 			dev_err(engine->dev, "failed to unprepare crypt hardware\n");
 
 		spin_lock_irqsave(&engine->queue_lock, flags);
-		engine->idling = false;
 		goto out;
 	}
 
@@ -410,7 +398,6 @@ struct crypto_engine *crypto_engine_alloc_init(struct device *dev, bool rt)
 	engine->rt = rt;
 	engine->running = false;
 	engine->busy = false;
-	engine->idling = false;
 	engine->cur_req_prepared = false;
 	engine->priv_data = dev;
 	snprintf(engine->name, sizeof(engine->name),
diff --git a/include/crypto/engine.h b/include/crypto/engine.h
index e29cd67f93c7..7e7cbd9ca3b5 100644
--- a/include/crypto/engine.h
+++ b/include/crypto/engine.h
@@ -21,7 +21,6 @@
 /*
  * struct crypto_engine - crypto hardware engine
  * @name: the engine name
- * @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
@@ -42,7 +41,6 @@
  */
 struct crypto_engine {
 	char			name[ENGINE_NAME_LEN];
-	bool			idling;
 	bool			busy;
 	bool			running;
 	bool			cur_req_prepared;
-- 
2.24.1