[PATCH v2 02/16] s390/vfio-ap: Provide access to queue objects and related info

[Anthony Krowiak <akrowiak@linux.ibm.com>]

Provide the following:

1. A function that returns a struct vfio_ap_queue object representing a
   queue that is bound to the vfio_ap device driver and is assigned to an
   mdev

2. A function that returns the number of queues that are or will be passed
   through to a guest when the mdev is attached to a guest.

There is already a function for #1; however, it is a static function in
drivers/s390/crypto/vfio_ap_ops.c. The function will be defined in the
drivers/s390/crypto/vfio_ap_private.h file and made non-static. Note that
it would probably make sense to ensure that the mdevs_lock is held for
this function, so a call to lockdep_assert_held(&matrix_dev->mdevs_lock)
will be added to the function implementation.

Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c     | 20 +++++++++++++++++---
 drivers/s390/crypto/vfio_ap_private.h |  4 ++++
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index ef3101f6865e..cd85866b81a0 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -203,12 +203,12 @@ static inline void get_update_locks_for_queue(struct vfio_ap_queue *q)
  * Return: the pointer to the vfio_ap_queue struct representing the queue or
  *	   NULL if the queue is not assigned to @matrix_mdev
  */
-static struct vfio_ap_queue *vfio_ap_mdev_get_queue(
-					struct ap_matrix_mdev *matrix_mdev,
-					int apqn)
+struct vfio_ap_queue *vfio_ap_mdev_get_queue(struct ap_matrix_mdev *matrix_mdev, int apqn)
 {
 	struct vfio_ap_queue *q;
 
+	lockdep_assert_held(&matrix_dev->mdevs_lock);
+
 	hash_for_each_possible(matrix_mdev->qtable.queues, q, mdev_qnode,
 			       apqn) {
 		if (q && q->apqn == apqn)
@@ -2098,6 +2098,20 @@ static void vfio_ap_mdev_request(struct vfio_device *vdev, unsigned int count)
 	release_update_locks_for_mdev(matrix_mdev);
 }
 
+int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix)
+{
+	unsigned long apid, apqi;
+	int num_queues = 0;
+
+	lockdep_assert_held(&matrix_dev->mdevs_lock);
+
+	for_each_set_bit_inv(apid, ap_matrix->apm, AP_DEVICES)
+		for_each_set_bit_inv(apqi, ap_matrix->aqm, AP_DOMAINS)
+			num_queues++;
+
+	return num_queues;
+}
+
 static int vfio_ap_mdev_get_device_info(unsigned long arg)
 {
 	unsigned long minsz;
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 39c85bab05c3..d66586825ef4 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -153,6 +153,10 @@ struct vfio_ap_queue {
 	struct ap_tapq_hwinfo hwinfo;
 };
 
+struct vfio_ap_queue *vfio_ap_mdev_get_queue(struct ap_matrix_mdev *matrix_mdev, int apqn);
+
+int vfio_ap_mdev_get_num_queues(struct ap_matrix *ap_matrix);
+
 int vfio_ap_mdev_register(void);
 void vfio_ap_mdev_unregister(void);
 
-- 
2.52.0