Re: [PATCH v7 04/15] s390/vfio-ap: implement in-use callback for vfio_ap driver

[Cornelia Huck <cohuck@redhat.com>]

On Tue,  7 Apr 2020 15:20:04 -0400
Tony Krowiak <akrowiak@linux.ibm.com> wrote:

> Let's implement the callback to indicate when an APQN
> is in use by the vfio_ap device driver. The callback is
> invoked whenever a change to the apmask or aqmask would
> result in one or more queue devices being removed from the driver. The
> vfio_ap device driver will indicate a resource is in use
> if the APQN of any of the queue devices to be removed are assigned to
> any of the matrix mdevs under the driver's control.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> ---
>  drivers/s390/crypto/vfio_ap_drv.c     |  1 +
>  drivers/s390/crypto/vfio_ap_ops.c     | 47 +++++++++++++++++----------
>  drivers/s390/crypto/vfio_ap_private.h |  2 ++
>  3 files changed, 33 insertions(+), 17 deletions(-)

> @@ -1369,3 +1371,14 @@ void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
>  	kfree(q);
>  	mutex_unlock(&matrix_dev->lock);
>  }
> +
> +bool vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm)
> +{
> +	bool in_use;
> +
> +	mutex_lock(&matrix_dev->lock);
> +	in_use = vfio_ap_mdev_verify_no_sharing(NULL, apm, aqm) ? true : false;

Maybe

in_use = !!vfio_ap_mdev_verify_no_sharing(NULL, apm, aqm);

?

> +	mutex_unlock(&matrix_dev->lock);
> +
> +	return in_use;
> +}