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Date:   Thu, 16 Apr 2020 13:18:45 +0200
From:   Cornelia Huck <cohuck@redhat.com>
To:     Tony Krowiak <akrowiak@linux.ibm.com>
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, freude@linux.ibm.com, borntraeger@de.ibm.com,
        mjrosato@linux.ibm.com, pmorel@linux.ibm.com, pasic@linux.ibm.com,
        alex.williamson@redhat.com, kwankhede@nvidia.com,
        jjherne@linux.ibm.com, fiuczy@linux.ibm.com
Subject: Re: [PATCH v7 04/15] s390/vfio-ap: implement in-use callback for
 vfio_ap driver
Message-ID: <20200416131845.3ef6b3b5.cohuck@redhat.com>
In-Reply-To: <20200407192015.19887-5-akrowiak@linux.ibm.com>
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        <20200407192015.19887-5-akrowiak@linux.ibm.com>
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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;
> +}