[congwang:bpf 5/5] net/ipv4/tcp.c:566:11: error: implicit declaration of function 'tcp_bpf_poll'

[kernel test robot <lkp@intel.com>]

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tree:   https://github.com/congwang/linux.git bpf
head:   5d467183b34e09531688cab9bae950fa6d5d04d3
commit: 5d467183b34e09531688cab9bae950fa6d5d04d3 [5/5] tcp_bpf: poll psock queues too in tcp_poll()
config: x86_64-randconfig-a001-20210918 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c8b3d7d6d6de37af68b2f379d0e37304f78e115f)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/congwang/linux/commit/5d467183b34e09531688cab9bae950fa6d5d04d3
        git remote add congwang https://github.com/congwang/linux.git
        git fetch --no-tags congwang bpf
        git checkout 5d467183b34e09531688cab9bae950fa6d5d04d3
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> net/ipv4/tcp.c:566:11: error: implicit declaration of function 'tcp_bpf_poll' [-Werror,-Wimplicit-function-declaration]
                   mask |= tcp_bpf_poll(sk);
                           ^
   1 error generated.


vim +/tcp_bpf_poll +566 net/ipv4/tcp.c

   494	
   495	/*
   496	 *	Wait for a TCP event.
   497	 *
   498	 *	Note that we don't need to lock the socket, as the upper poll layers
   499	 *	take care of normal races (between the test and the event) and we don't
   500	 *	go look at any of the socket buffers directly.
   501	 */
   502	__poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
   503	{
   504		__poll_t mask;
   505		struct sock *sk = sock->sk;
   506		const struct tcp_sock *tp = tcp_sk(sk);
   507		int state;
   508	
   509		sock_poll_wait(file, sock, wait);
   510	
   511		state = inet_sk_state_load(sk);
   512		if (state == TCP_LISTEN)
   513			return inet_csk_listen_poll(sk);
   514	
   515		/* Socket is not locked. We are protected from async events
   516		 * by poll logic and correct handling of state changes
   517		 * made by other threads is impossible in any case.
   518		 */
   519	
   520		mask = 0;
   521	
   522		/*
   523		 * EPOLLHUP is certainly not done right. But poll() doesn't
   524		 * have a notion of HUP in just one direction, and for a
   525		 * socket the read side is more interesting.
   526		 *
   527		 * Some poll() documentation says that EPOLLHUP is incompatible
   528		 * with the EPOLLOUT/POLLWR flags, so somebody should check this
   529		 * all. But careful, it tends to be safer to return too many
   530		 * bits than too few, and you can easily break real applications
   531		 * if you don't tell them that something has hung up!
   532		 *
   533		 * Check-me.
   534		 *
   535		 * Check number 1. EPOLLHUP is _UNMASKABLE_ event (see UNIX98 and
   536		 * our fs/select.c). It means that after we received EOF,
   537		 * poll always returns immediately, making impossible poll() on write()
   538		 * in state CLOSE_WAIT. One solution is evident --- to set EPOLLHUP
   539		 * if and only if shutdown has been made in both directions.
   540		 * Actually, it is interesting to look how Solaris and DUX
   541		 * solve this dilemma. I would prefer, if EPOLLHUP were maskable,
   542		 * then we could set it on SND_SHUTDOWN. BTW examples given
   543		 * in Stevens' books assume exactly this behaviour, it explains
   544		 * why EPOLLHUP is incompatible with EPOLLOUT.	--ANK
   545		 *
   546		 * NOTE. Check for TCP_CLOSE is added. The goal is to prevent
   547		 * blocking on fresh not-connected or disconnected socket. --ANK
   548		 */
   549		if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
   550			mask |= EPOLLHUP;
   551		if (sk->sk_shutdown & RCV_SHUTDOWN)
   552			mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
   553	
   554		/* Connected or passive Fast Open socket? */
   555		if (state != TCP_SYN_SENT &&
   556		    (state != TCP_SYN_RECV || rcu_access_pointer(tp->fastopen_rsk))) {
   557			int target = sock_rcvlowat(sk, 0, INT_MAX);
   558	
   559			if (READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq) &&
   560			    !sock_flag(sk, SOCK_URGINLINE) &&
   561			    tp->urg_data)
   562				target++;
   563	
   564			if (tcp_stream_is_readable(sk, target))
   565				mask |= EPOLLIN | EPOLLRDNORM;
 > 566			mask |= tcp_bpf_poll(sk);
   567	
   568			if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
   569				if (__sk_stream_is_writeable(sk, 1)) {
   570					mask |= EPOLLOUT | EPOLLWRNORM;
   571				} else {  /* send SIGIO later */
   572					sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
   573					set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
   574	
   575					/* Race breaker. If space is freed after
   576					 * wspace test but before the flags are set,
   577					 * IO signal will be lost. Memory barrier
   578					 * pairs with the input side.
   579					 */
   580					smp_mb__after_atomic();
   581					if (__sk_stream_is_writeable(sk, 1))
   582						mask |= EPOLLOUT | EPOLLWRNORM;
   583				}
   584			} else
   585				mask |= EPOLLOUT | EPOLLWRNORM;
   586	
   587			if (tp->urg_data & TCP_URG_VALID)
   588				mask |= EPOLLPRI;
   589		} else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
   590			/* Active TCP fastopen socket with defer_connect
   591			 * Return EPOLLOUT so application can call write()
   592			 * in order for kernel to generate SYN+data
   593			 */
   594			mask |= EPOLLOUT | EPOLLWRNORM;
   595		}
   596		/* This barrier is coupled with smp_wmb() in tcp_reset() */
   597		smp_rmb();
   598		if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
   599			mask |= EPOLLERR;
   600	
   601		return mask;
   602	}
   603	EXPORT_SYMBOL(tcp_poll);
   604	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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