[v17,02/15] s390/vfio-ap: use new AP bus interface to search for queue devices

Commit Message

Anthony Krowiak Oct. 21, 2021, 3:23 p.m. UTC

This patch refactors the vfio_ap device driver to use the AP bus's
ap_get_qdev() function to retrieve the vfio_ap_queue struct containing
information about a queue that is bound to the vfio_ap device driver.
The bus's ap_get_qdev() function retrieves the queue device from a
hashtable keyed by APQN. This is much more efficient than looping over
the list of devices attached to the AP bus by several orders of
magnitude.

Signed-off-by: Tony Krowiak <[e-mail]>
Reviewed-by: Halil Pasic <[e-mail]>
Reviewed-by: Jason J. Herne <[e-mail]>
---
 drivers/s390/crypto/vfio_ap_ops.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

Comments

Halil Pasic Dec. 27, 2021, 8:25 a.m. UTC | #1

On Thu, 21 Oct 2021 11:23:19 -0400
Tony Krowiak <[e-mail]> wrote:

> his patch refactors the vfio_ap device driver to use the AP bus's
> ap_get_qdev() function to retrieve the vfio_ap_queue struct containing
> information about a queue that is bound to the vfio_ap device driver.
> The bus's ap_get_qdev() function retrieves the queue device from a
> hashtable keyed by APQN. This is much more efficient than looping over
> the list of devices attached to the AP bus by several orders of
> magnitude.
> 
> Signed-off-by: Tony Krowiak <[e-mail]>
> Reviewed-by: Halil Pasic <[e-mail]>

I assume nothing changed here, and nothing significant changed around
this patch (context). If I'm wrong, please tell me and I will
re-evaluate.

Regards,
Halil

Anthony Krowiak Jan. 11, 2022, 5:32 p.m. UTC | #2

On 12/27/21 03:25, Halil Pasic wrote:
> On Thu, 21 Oct 2021 11:23:19 -0400
> Tony Krowiak <[e-mail]> wrote:
>
>> his patch refactors the vfio_ap device driver to use the AP bus's
>> ap_get_qdev() function to retrieve the vfio_ap_queue struct containing
>> information about a queue that is bound to the vfio_ap device driver.
>> The bus's ap_get_qdev() function retrieves the queue device from a
>> hashtable keyed by APQN. This is much more efficient than looping over
>> the list of devices attached to the AP bus by several orders of
>> magnitude.
>>
>> Signed-off-by: Tony Krowiak <[e-mail]>
>> Reviewed-by: Halil Pasic <[e-mail]>
> I assume nothing changed here, and nothing significant changed around
> this patch (context). If I'm wrong, please tell me and I will
> re-evaluate.

rebase to this patch -> delete the patch -> fix resultant conflicts

>
> Regards,
> Halil

Patch

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 02275d246b39..7a9d1b04ecd4 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -28,13 +28,6 @@  static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev);
 static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
 static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
 
-static int match_apqn(struct device *dev, const void *data)
-{
-	struct vfio_ap_queue *q = dev_get_drvdata(dev);
-
-	return (q->apqn == *(int *)(data)) ? 1 : 0;
-}
-
 /**
  * vfio_ap_get_queue - retrieve a queue with a specific APQN from a list
  * @matrix_mdev: the associated mediated matrix
@@ -1183,15 +1176,17 @@  static int vfio_ap_mdev_group_notifier(struct notifier_block *nb,
 
 static struct vfio_ap_queue *vfio_ap_find_queue(int apqn)
 {
-	struct device *dev;
+	struct ap_queue *queue;
 	struct vfio_ap_queue *q = NULL;
 
-	dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
-				 &apqn, match_apqn);
-	if (dev) {
-		q = dev_get_drvdata(dev);
-		put_device(dev);
-	}
+	queue = ap_get_qdev(apqn);
+	if (!queue)
+		return NULL;
+
+	if (queue->ap_dev.device.driver == &matrix_dev->vfio_ap_drv->driver)
+		q = dev_get_drvdata(&queue->ap_dev.device);
+
+	put_device(&queue->ap_dev.device);
 
 	return q;
 }