taglinefilesource code
sock_rspace310include/net/sock.hextern unsigned long    sock_rspace(struct sock *sk);
sock_rspace385net/ipv4/packet.csock_rspace,
sock_rspace285net/ipv4/raw.csock_rspace,
sock_rspace5142net/ipv4/tcp.csock_rspace,
sock_rspace663net/ipv4/udp.csock_rspace,