s390/vfio-ap: use new AP bus interface to search for queue devices

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>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index a7d2a95..634e23a 100644 (file)
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -30,13 +30,6 @@ 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
@@ -1286,15 +1279,17 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev)
 
 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;
 }