From c7004482e8dcb7c3c72666395cfa98a216a4fb70 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 6 Oct 2008 10:43:54 -0700 Subject: [PATCH] tcp: Respect SO_RCVLOWAT in tcp_poll(). Based upon a report by Vito Caputo. Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 1ab341e5d3e..7d81a1ee550 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -384,13 +384,17 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait) /* Connected? */ if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV)) { + int target = sock_rcvlowat(sk, 0, INT_MAX); + + if (tp->urg_seq == tp->copied_seq && + !sock_flag(sk, SOCK_URGINLINE) && + tp->urg_data) + target--; + /* Potential race condition. If read of tp below will * escape above sk->sk_state, we can be illegally awaken * in SYN_* states. */ - if ((tp->rcv_nxt != tp->copied_seq) && - (tp->urg_seq != tp->copied_seq || - tp->rcv_nxt != tp->copied_seq + 1 || - sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data)) + if (tp->rcv_nxt - tp->copied_seq >= target) mask |= POLLIN | POLLRDNORM; if (!(sk->sk_shutdown & SEND_SHUTDOWN)) { -- 2.41.1