llc_conn_remove_acked_pdus
int llc_conn_remove_acked_pdus(struct sock *conn, u8 nr, u16 *how_many_unacked);
acked = llc_conn_remove_acked_pdus(sk, llc->last_nr, &unacked);
llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);