why a static function is in kernel symbol table

Hi all, I happened to find that a static function show up in kernel symbol table: static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle, int push_one, gfp_t gfp); I feel puzzled. The only difference between this function with other static functions in net/ipv4/tcp_output.c is that tcp_write_xmit is declared at the very beginning of the file. However, I tried putting declaration of another static function in front of tcp_write_xmit, but it still did not show up in newly compiled vmlinux. Could anyone kindly cast some light? Thanks Ji