This patch refactor's 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>
---
 drivers/s390/crypto/vfio_ap_drv.c     | 27 ++-------
 drivers/s390/crypto/vfio_ap_ops.c     | 82 +++++++++++++++------------
 drivers/s390/crypto/vfio_ap_private.h |  8 ++-
 3 files changed, 58 insertions(+), 59 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c 
b/drivers/s390/crypto/vfio_ap_drv.c
index be2520cc010b..59233cf7419d 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -51,15 +51,9 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids);
  */
 static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
 {
-       struct vfio_ap_queue *q;
-
-       q = kzalloc(sizeof(*q), GFP_KERNEL);
-       if (!q)
-               return -ENOMEM;
-       dev_set_drvdata(&apdev->device, q);
-       q->apqn = to_ap_queue(&apdev->device)->qid;
-       q->saved_isc = VFIO_AP_ISC_INVALID;
-       return 0;
+       struct ap_queue *queue = to_ap_queue(&apdev->device);
+
+       return vfio_ap_mdev_probe_queue(queue);
 }
 
 /**
@@ -70,18 +64,9 @@ static int vfio_ap_queue_dev_probe(struct ap_device *apdev)
  */
 static void vfio_ap_queue_dev_remove(struct ap_device *apdev)
 {
-       struct vfio_ap_queue *q;
-       int apid, apqi;
-
-       mutex_lock(&matrix_dev->lock);
-       q = dev_get_drvdata(&apdev->device);
-       dev_set_drvdata(&apdev->device, NULL);
-       apid = AP_QID_CARD(q->apqn);
-       apqi = AP_QID_QUEUE(q->apqn);
-       vfio_ap_mdev_reset_queue(apid, apqi, 1);
-       vfio_ap_irq_disable(q);
-       kfree(q);
-       mutex_unlock(&matrix_dev->lock);
+       struct ap_queue *queue = to_ap_queue(&apdev->device);
+
+       vfio_ap_mdev_remove_queue(queue);
 }
 
 static void vfio_ap_matrix_dev_release(struct device *dev)
diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
b/drivers/s390/crypto/vfio_ap_ops.c
index e0bde8518745..7c96b6fd9f70 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -26,43 +26,26 @@
 
 static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);
 
-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
+ * vfio_ap_get_queue: Retrieve a queue with a specific APQN.
  * @apqn: The queue APQN
  *
- * Retrieve a queue with a specific APQN from the list of the
- * devices of the vfio_ap_drv.
- * Verify that the APID and the APQI are set in the matrix.
+ * Retrieve a queue with a specific APQN from the AP queue devices attached to
+ * the AP bus.
  *
- * Returns the pointer to the associated vfio_ap_queue
+ * Returns the pointer to the vfio_ap_queue with the specified APQN, or NULL.
  */
-static struct vfio_ap_queue *vfio_ap_get_queue(
-                                       struct ap_matrix_mdev *matrix_mdev,
-                                       int apqn)
+static struct vfio_ap_queue *vfio_ap_get_queue(unsigned long apqn)
 {
+       struct ap_queue *queue;
        struct vfio_ap_queue *q;
-       struct device *dev;
 
-       if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm))
-               return NULL;
-       if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm))
+       queue = ap_get_qdev(apqn);
+       if (!queue)
                return NULL;
 
-       dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
-                                &apqn, match_apqn);
-       if (!dev)
-               return NULL;
-       q = dev_get_drvdata(dev);
-       q->matrix_mdev = matrix_mdev;
-       put_device(dev);
+       q = dev_get_drvdata(&queue->ap_dev.device);
+       put_device(&queue->ap_dev.device);
 
        return q;
 }
@@ -293,10 +276,11 @@ static int handle_pqap(struct kvm_vcpu *vcpu)
        matrix_mdev = container_of(vcpu->kvm->arch.crypto.pqap_hook,
                                   struct ap_matrix_mdev, pqap_hook);
 
-       q = vfio_ap_get_queue(matrix_mdev, apqn);
+       q = vfio_ap_get_queue(apqn);
        if (!q)
                goto out_unlock;
 
+       q->matrix_mdev = matrix_mdev;
        status = vcpu->run->s.regs.gprs[1];
 
        /* If IR bit(16) is set we enable the interrupt */
@@ -1116,16 +1100,11 @@ static int vfio_ap_mdev_group_notifier(struct 
notifier_block *nb,
 
 static void vfio_ap_irq_disable_apqn(int apqn)
 {
-       struct device *dev;
        struct vfio_ap_queue *q;
 
-       dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,
-                                &apqn, match_apqn);
-       if (dev) {
-               q = dev_get_drvdata(dev);
+       q = vfio_ap_get_queue(apqn);
+       if (q)
                vfio_ap_irq_disable(q);
-               put_device(dev);
-       }
 }
 
 int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
@@ -1302,3 +1281,36 @@ void vfio_ap_mdev_unregister(void)
 {
        mdev_unregister_device(&matrix_dev->device);
 }
+
+int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
+{
+       struct vfio_ap_queue *q;
+
+       q = kzalloc(sizeof(*q), GFP_KERNEL);
+       if (!q)
+               return -ENOMEM;
+
+       mutex_lock(&matrix_dev->lock);
+       dev_set_drvdata(&queue->ap_dev.device, q);
+       q->apqn = queue->qid;
+       q->saved_isc = VFIO_AP_ISC_INVALID;
+       mutex_unlock(&matrix_dev->lock);
+
+       return 0;
+}
+
+void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
+{
+       struct vfio_ap_queue *q;
+       int apid, apqi;
+
+       mutex_lock(&matrix_dev->lock);
+       q = dev_get_drvdata(&queue->ap_dev.device);
+       dev_set_drvdata(&queue->ap_dev.device, NULL);
+       apid = AP_QID_CARD(q->apqn);
+       apqi = AP_QID_QUEUE(q->apqn);
+       vfio_ap_mdev_reset_queue(apid, apqi, 1);
+       vfio_ap_irq_disable(q);
+       kfree(q);
+       mutex_unlock(&matrix_dev->lock);
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h 
b/drivers/s390/crypto/vfio_ap_private.h
index f46dde56b464..a2aa05bec718 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -18,6 +18,7 @@
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/kvm_host.h>
+#include <linux/hashtable.h>
 
 #include "ap_bus.h"
 
@@ -90,8 +91,6 @@ struct ap_matrix_mdev {
 
 extern int vfio_ap_mdev_register(void);
 extern void vfio_ap_mdev_unregister(void);
-int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,
-                            unsigned int retry);
 
 struct vfio_ap_queue {
        struct ap_matrix_mdev *matrix_mdev;
@@ -100,5 +99,8 @@ struct vfio_ap_queue {
 #define VFIO_AP_ISC_INVALID 0xff
        unsigned char saved_isc;
 };
-struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q);
+
+int vfio_ap_mdev_probe_queue(struct ap_queue *queue);
+void vfio_ap_mdev_remove_queue(struct ap_queue *queue);
+
 #endif /* _VFIO_AP_PRIVATE_H_ */
-- 
2.21.1

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