Message ID | 20190306180136.68112-1-soheil.kdev@gmail.com |
---|---|
State | Accepted |
Delegated to: | David Miller |
Headers | show |
Series | [net] tcp: do not report TCP_CM_INQ of 0 for closed connections | expand |
From: Soheil Hassas Yeganeh <soheil.kdev@gmail.com> Date: Wed, 6 Mar 2019 13:01:36 -0500 > From: Soheil Hassas Yeganeh <soheil@google.com> > > Returning 0 as inq to userspace indicates there is no more data to > read, and the application needs to wait for EPOLLIN. For a connection > that has received FIN from the remote peer, however, the application > must continue reading until getting EOF (return value of 0 > from tcp_recvmsg) or an error, if edge-triggered epoll (EPOLLET) is > being used. Otherwise, the application will never receive a new > EPOLLIN, since there is no epoll edge after the FIN. > > Return 1 when there is no data left on the queue but the > connection has received FIN, so that the applications continue > reading. > > Fixes: b75eba76d3d72 (tcp: send in-queue bytes in cmsg upon read) > Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> > Acked-by: Neal Cardwell <ncardwell@google.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > Acked-by: Yuchung Cheng <ycheng@google.com> Applied and queued up for -stable, thank you.
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index ad07dd71063da..8b25017e0dc93 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1933,6 +1933,11 @@ static int tcp_inq_hint(struct sock *sk) inq = tp->rcv_nxt - tp->copied_seq; release_sock(sk); } + /* After receiving a FIN, tell the user-space to continue reading + * by returning a non-zero inq. + */ + if (inq == 0 && sock_flag(sk, SOCK_DONE)) + inq = 1; return inq; }