virtio_scsi: move kick event out from virtscsi_init

We currently kick event within virtscsi_init,
before host is fully initialized.

This can in theory confuse guest if device
consumes the buffers immediately.

To fix,  move virtscsi_kick_event_all out to scan/restore.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/scsi/virtio_scsi.c

@@ -853,7 +853,11 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 
 static void virtscsi_scan(struct virtio_device *vdev)
 {
-	struct Scsi_Host *shost = (struct Scsi_Host *)vdev->priv;
+	struct Scsi_Host *shost = virtio_scsi_host(vdev);
+	struct virtio_scsi *vscsi = shost_priv(shost);
+
+	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
+		virtscsi_kick_event_all(vscsi);
 
 	scsi_scan_host(shost);
 }
@@ -916,9 +920,6 @@ static int virtscsi_init(struct virtio_device *vdev,
 	virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE);
 	virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE);
 
-	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
-		virtscsi_kick_event_all(vscsi);
-
 	err = 0;
 
 out:
@@ -1048,8 +1049,13 @@ static int virtscsi_restore(struct virtio_device *vdev)
 		return err;
 
 	err = register_hotcpu_notifier(&vscsi->nb);
-	if (err)
+	if (err) {
 		vdev->config->del_vqs(vdev);
+		return err;
+	}
+
+	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
+		virtscsi_kick_event_all(vscsi);
 
 	return err;
 }