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authorSoheil Hassas Yeganeh <soheil@google.com>2019-03-06 13:01:36 -0500
committerDavid S. Miller <davem@davemloft.net>2019-03-06 11:00:50 -0800
commit6466e715651f9f358e60c5ea4880e4731325827f (patch)
treeb7becb9ea1b8fd50abbca27ddd36c0b379485b0a /net
parent6caabe7f197d3466d238f70915d65301f1716626 (diff)
tcp: do not report TCP_CM_INQ of 0 for closed connections
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> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index dbb08140cdc9..6baa6dc1b13b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1937,6 +1937,11 @@ 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;
}