p_pgid
#define USB_PROC_GET_GID(td) (td)->p_pgid
if (p->p_pgid != (pid_t)id)
id = curproc->p_pgid;
id = curproc->p_pgid;
if (p->p_pgid == p->p_pid || (pg = pgfind(p->p_pid)) != NULL) {