[PATCH v13 04/15] s390/vfio-ap: use new AP bus interface to search for queue devices

[Tony Krowiak]

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 <akrow...@linux.ibm.com>
Reviewed-by: Halil Pasic <pa...@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
b/drivers/s390/crypto/vfio_ap_ops.c
index a83d6e75361b..835c963ae16d 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -27,13 +27,6 @@
 static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
 static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
 
-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
@@ -49,7 +42,7 @@ static struct vfio_ap_queue *vfio_ap_get_queue(
                                        struct ap_matrix_mdev *matrix_mdev,
                                        int apqn)
 {
-       struct vfio_ap_queue *q;
+       struct vfio_ap_queue *q = NULL;
 
        if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm))
                return NULL;
@@ -1124,15 +1117,17 @@ 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;
+
+       put_device(&queue->ap_dev.device);
+
+       if (queue->ap_dev.device.driver == &matrix_dev->vfio_ap_drv->driver)
+               q = dev_get_drvdata(&queue->ap_dev.device);
 
        return q;
 }
-- 
2.21.1