Re: [PATCH v2 RFC 3/3] virtio_ccw: invoke virtio_driver's notify() on CIO_GONE notification

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 21, 2013 at 03:45:33PM +0100, Heinz Graalfs wrote:
> virtio_ccw's notify() callback for the common IO layer invokes
> virtio_driver's notify() callback to pass-on information to a
> backend driver if an online device disappeared.
> 
> Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>

simple question: is this serialized with device removal?
If this races with removal we have a problem.

> ---
>  drivers/s390/kvm/virtio_ccw.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
> index 35b9aaa..682f688 100644
> --- a/drivers/s390/kvm/virtio_ccw.c
> +++ b/drivers/s390/kvm/virtio_ccw.c
> @@ -27,6 +27,7 @@
>  #include <linux/module.h>
>  #include <linux/io.h>
>  #include <linux/kvm_para.h>
> +#include <linux/notifier.h>
>  #include <asm/setup.h>
>  #include <asm/irq.h>
>  #include <asm/cio.h>
> @@ -1064,8 +1065,18 @@ out_free:
>  
>  static int virtio_ccw_cio_notify(struct ccw_device *cdev, int event)
>  {
> -	/* TODO: Check whether we need special handling here. */
> -	return 0;
> +	int rc;
> +	struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
> +
> +	switch (event) {
> +	case CIO_GONE:
> +		rc = notify_virtio_device(&vcdev->vdev, VDEV_GONE);
> +		break;
> +	default:
> +		rc = NOTIFY_DONE;
> +		break;
> +	}
> +	return rc;
>  }
>  
>  static struct ccw_device_id virtio_ids[] = {
> -- 
> 1.8.3.1