[PATCH v18 03/18] s390/vfio-ap: use new AP bus interface to search for queue devices

Tony Krowiak
2022-02-15T00:50:55Z

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 <akrowiak@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
---
drivers/s390/crypto/vfio_ap_ops.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index abc0b9b88386..2b6b61719cce 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
@@ -1193,15 +1186,17 @@ 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;
}
--
2.31.1