pvcalls_back_global
down(&pvcalls_back_global.frontends_lock);
up(&pvcalls_back_global.frontends_lock);
sema_init(&pvcalls_back_global.frontends_lock, 1);
INIT_LIST_HEAD(&pvcalls_back_global.frontends);
down(&pvcalls_back_global.frontends_lock);
&pvcalls_back_global.frontends, list) {
up(&pvcalls_back_global.frontends_lock);
} pvcalls_back_global;
down(&pvcalls_back_global.frontends_lock);
list_add_tail(&fedata->list, &pvcalls_back_global.frontends);
up(&pvcalls_back_global.frontends_lock);