Re: [PATCH v10 05/16] s390/vfio-ap: implement in-use callback for vfio_ap driver

[Halil Pasic]

On Fri, 21 Aug 2020 15:56:05 -0400
Tony Krowiak <akrowiak@xxxxxxxxxxxxx> wrote:

> +
> +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);
> +	mutex_unlock(&matrix_dev->lock);

See also my comment for patch 4. AFAIU as soon as you release the lock
the in_use may become outdated in any moment.

> +
> +	return in_use;
> +}