[1/1] HIFN: schedule callback invocation to tasklet.

[1/1] HIFN: schedule callback invocation to tasklet.

[Evgeniy Polyakov]

Hi.

This patch forces HIFN driver to invoke crypto request callbacks from
tasklet (softirq context) instead of hardirq context, since network
stack expects it to be called from bottom halves.

It is done by simply scheduling callback invocation via dedicated
tasklet. Workqueue solution was dropped because of tooo slow
rescheduling performance (7 times slower than tasklet, for mode details
one can check this link:
http://tservice.net.ru/~s0mbre/blog/devel/other/2007_11_09.html).

Driver passed all AES and DES tests in tcryt.c module.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

diff --git a/drivers/crypto/hifn_795x.c b/drivers/crypto/hifn_795x.c
index e152917..f5aa939 100644
--- a/drivers/crypto/hifn_795x.c
+++ b/drivers/crypto/hifn_795x.c
@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/interrupt.h>
 #include <linux/crypto.h>
 
 #include <crypto/algapi.h>
@@ -425,6 +426,8 @@ struct hifn_device
 
 	u8			snum;
 
+	struct tasklet_struct	tasklet;
+
 	struct crypto_queue 	queue;
 	struct list_head	alg_list;
 };
@@ -1881,7 +1884,7 @@ static irqreturn_t hifn_interrupt(int irq, void *data)
 		hifn_write_1(dev, HIFN_1_DMA_IER, dev->dmareg);
 	}
 
-	hifn_check_for_completion(dev, 0);
+	tasklet_schedule(&dev->tasklet);
 	hifn_clear_rings(dev);
 
 	return IRQ_HANDLED;
@@ -2414,6 +2417,19 @@ err_out_exit:
 	return err;
 }
 
+static void hifn_tasklet_callback(unsigned long data)
+{
+	struct hifn_device *dev = (struct hifn_device *)data;
+
+	/*
+	 * This is ok to call this without lock being held,
+	 * althogh it modifies some parameters used in parallel,
+	 * (like dev->success), but they are used in process
+	 * context or update is atomic (like setting dev->sa[i] to NULL).
+	 */
+	hifn_check_for_completion(dev, 0);
+}
+
 static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	int err, i;
@@ -2495,6 +2511,8 @@ static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	pci_set_drvdata(pdev, dev);
 
+	tasklet_init(&dev->tasklet, hifn_tasklet_callback, (unsigned long)dev);
+
 	crypto_init_queue(&dev->queue, 1);
 
 	err = request_irq(dev->irq, hifn_interrupt, IRQF_SHARED, dev->name, dev);

-- 
	Evgeniy Polyakov

Re: [1/1] HIFN: schedule callback invocation to tasklet.

[Evgeniy Polyakov]

On Fri, Nov 09, 2007 at 07:12:14PM +0300, Evgeniy Polyakov (johnpol@2ka.mipt.ru) wrote:
> This patch forces HIFN driver to invoke crypto request callbacks from
> tasklet (softirq context) instead of hardirq context, since network
> stack expects it to be called from bottom halves.

And first patch is obviously wrong, since it does not stop tasklet on
exit path, please apply given one.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

diff --git a/drivers/crypto/hifn_795x.c b/drivers/crypto/hifn_795x.c
index e152917..0a7c07b 100644
--- a/drivers/crypto/hifn_795x.c
+++ b/drivers/crypto/hifn_795x.c
@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/mm.h>
 #include <linux/highmem.h>
+#include <linux/interrupt.h>
 #include <linux/crypto.h>
 
 #include <crypto/algapi.h>
@@ -425,6 +426,8 @@ struct hifn_device
 
 	u8			snum;
 
+	struct tasklet_struct	tasklet;
+
 	struct crypto_queue 	queue;
 	struct list_head	alg_list;
 };
@@ -1881,7 +1884,7 @@ static irqreturn_t hifn_interrupt(int irq, void *data)
 		hifn_write_1(dev, HIFN_1_DMA_IER, dev->dmareg);
 	}
 
-	hifn_check_for_completion(dev, 0);
+	tasklet_schedule(&dev->tasklet);
 	hifn_clear_rings(dev);
 
 	return IRQ_HANDLED;
@@ -2414,6 +2417,19 @@ err_out_exit:
 	return err;
 }
 
+static void hifn_tasklet_callback(unsigned long data)
+{
+	struct hifn_device *dev = (struct hifn_device *)data;
+
+	/*
+	 * This is ok to call this without lock being held,
+	 * althogh it modifies some parameters used in parallel,
+	 * (like dev->success), but they are used in process
+	 * context or update is atomic (like setting dev->sa[i] to NULL).
+	 */
+	hifn_check_for_completion(dev, 0);
+}
+
 static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	int err, i;
@@ -2495,6 +2511,8 @@ static int hifn_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	pci_set_drvdata(pdev, dev);
 
+	tasklet_init(&dev->tasklet, hifn_tasklet_callback, (unsigned long)dev);
+
 	crypto_init_queue(&dev->queue, 1);
 
 	err = request_irq(dev->irq, hifn_interrupt, IRQF_SHARED, dev->name, dev);
@@ -2530,6 +2548,7 @@ err_out_stop_device:
 	hifn_stop_device(dev);
 err_out_free_irq:
 	free_irq(dev->irq, dev->name);
+	tasklet_kill(&dev->tasklet);
 err_out_free_desc:
 	pci_free_consistent(pdev, sizeof(struct hifn_dma),
 			dev->desc_virt, dev->desc_dma);
@@ -2569,6 +2588,7 @@ static void hifn_remove(struct pci_dev *pdev)
 		hifn_stop_device(dev);
 
 		free_irq(dev->irq, dev->name);
+		tasklet_kill(&dev->tasklet);
 
 		hifn_flush(dev);
 

-- 
	Evgeniy Polyakov

Re: [1/1] HIFN: schedule callback invocation to tasklet.

[Herbert Xu]

On Fri, Nov 09, 2007 at 09:31:56PM +0300, Evgeniy Polyakov wrote:
> On Fri, Nov 09, 2007 at 07:12:14PM +0300, Evgeniy Polyakov (johnpol@2ka.mipt.ru) wrote:
> > This patch forces HIFN driver to invoke crypto request callbacks from
> > tasklet (softirq context) instead of hardirq context, since network
> > stack expects it to be called from bottom halves.
> 
> And first patch is obviously wrong, since it does not stop tasklet on
> exit path, please apply given one.
> 
> Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>

Patch applied.  Thanks Evgeniy!
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