vhost_scsi: Handle vhost_vq_work_queue failures for TMFs

vhost_vq_work_queue will never fail when queueing the TMF's response
handling because a guest can only send us TMFs when the device is fully
setup so there is always a worker at that time. In the next patches we
will modify the worker code so it handles SIGKILL by exiting before
outstanding commands/TMFs have sent their responses. In that case
vhost_vq_work_queue can fail when we try to send a response.

This has us just free the TMF's resources since at this time the guest
won't be able to get a response even if we could send it.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-6-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/scsi.c

@@ -1309,7 +1309,8 @@ static void vhost_scsi_tmf_flush_work(struct work_struct *work)
 	 * send our response.
 	 */
 	vhost_dev_flush(vq->dev);
-	vhost_vq_work_queue(vq, &tmf->vwork);
+	if (!vhost_vq_work_queue(vq, &tmf->vwork))
+		vhost_scsi_release_tmf_res(tmf);
 }
 
 static void