From c7004482e8dcb7c3c72666395cfa98a216a4fb70 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
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 <davem@davemloft.net>
---
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 1ab341e5d3e0f..7d81a1ee5507c 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)) {
--
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