linux-kernel - [PATCH 7/7 v8] crypto:s5p-sss: Look for the next request in the queue

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Date:	Mon, 28 Apr 2014 16:14:59 +0530
From:	Naveen Krishna Chatradhi <ch.naveen@...sung.com>
To:	linux-crypto@...r.kernel.org, linux-samsung-soc@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, vzapolskiy@...il.com,
	herbert@...dor.apana.org.au, naveenkrishna.ch@...il.com,
	cpgs@...sung.com, t.figa@...sung.com, davem@...emloft.net
Subject: [PATCH 7/7 v8] crypto:s5p-sss: Look for the next request in the queue

Currently, the driver enqueues a request only if the busy bit is
false. And every request initiates a dequeue. If 2 requests arrive
simultaneously, only one of them will be dequeued.

To avoid this senario, we will enqueue the next request irrespective
of the system condition (that is what queue is here for). Also
schedule at a tasklet immediatly after the current request is done.
The tasklet will dequeue the next request in the queue, giving
continuous loop. tasklet will exit if there are no requests in the
queue.

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@...sung.com>
Acked-by: Herbert Xu <herbert@...dor.apana.org.au>
CC: David S. Miller <davem@...emloft.net>
CC: Vladimir Zapolskiy <vzapolskiy@...il.com>
TO: <linux-crypto@...r.kernel.org>
CC: <linux-samsung-soc@...r.kernel.org>
---
Changes since v7:
Added Acked-by from Herbert Xu
Changes since v6:
None

 drivers/crypto/s5p-sss.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
index ea7d478..47c568e 100644
--- a/drivers/crypto/s5p-sss.c
+++ b/drivers/crypto/s5p-sss.c
@@ -330,8 +330,12 @@ static void s5p_aes_tx(struct s5p_aes_dev *dev)
 		}
 
 		s5p_set_dma_outdata(dev, dev->sg_dst);
-	} else
+	} else {
 		s5p_aes_complete(dev, err);
+
+		dev->busy = true;
+		tasklet_schedule(&dev->tasklet);
+	}
 }
 
 static void s5p_aes_rx(struct s5p_aes_dev *dev)
@@ -469,10 +473,13 @@ static void s5p_tasklet_cb(unsigned long data)
 	spin_lock_irqsave(&dev->lock, flags);
 	backlog   = crypto_get_backlog(&dev->queue);
 	async_req = crypto_dequeue_request(&dev->queue);
-	spin_unlock_irqrestore(&dev->lock, flags);
 
-	if (!async_req)
+	if (!async_req) {
+		dev->busy = false;
+		spin_unlock_irqrestore(&dev->lock, flags);
 		return;
+	}
+	spin_unlock_irqrestore(&dev->lock, flags);
 
 	if (backlog)
 		backlog->complete(backlog, -EINPROGRESS);
@@ -491,14 +498,13 @@ static int s5p_aes_handle_req(struct s5p_aes_dev *dev,
 	int err;
 
 	spin_lock_irqsave(&dev->lock, flags);
+	err = ablkcipher_enqueue_request(&dev->queue, req);
 	if (dev->busy) {
-		err = -EAGAIN;
 		spin_unlock_irqrestore(&dev->lock, flags);
 		goto exit;
 	}
 	dev->busy = true;
 
-	err = ablkcipher_enqueue_request(&dev->queue, req);
 	spin_unlock_irqrestore(&dev->lock, flags);
 
 	tasklet_schedule(&dev->tasklet);
@@ -683,6 +689,7 @@ static int s5p_aes_probe(struct platform_device *pdev)
 		}
 	}
 
+	pdata->busy = false;
 	pdata->variant = variant;
 	pdata->dev = dev;
 	platform_set_drvdata(pdev, pdata);
-- 
1.7.9.5

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