From: David S. Miller <davem@davemloft.net>
Date: Tue, 22 Jul 2008 01:45:34 +0000 (-0700)
Subject: tcp: Fix bitmask test in tcp_syn_options()
X-Git-Tag: v2.6.27-rc1~860^2~17
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b32d13102d39ed411d152a7ffcc5f66d5b3b1b49;p=linux-2.6

tcp: Fix bitmask test in tcp_syn_options()

As reported by Alexey Dobriyan:

	  CHECK   net/ipv4/tcp_output.c
	net/ipv4/tcp_output.c:475:7: warning: dubious: !x & y

And sparse is damn right!

	if (unlikely(!OPTION_TS & opts->options))
		    ^^^
		size += TCPOLEN_SACKPERM_ALIGNED;

OPTION_TS is (1 << 1), so condition will never trigger.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 1fa683c0ba..a00532de2a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -472,7 +472,7 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 	}
 	if (likely(sysctl_tcp_sack)) {
 		opts->options |= OPTION_SACK_ADVERTISE;
-		if (unlikely(!OPTION_TS & opts->options))
+		if (unlikely(!(OPTION_TS & opts->options)))
 			size += TCPOLEN_SACKPERM_ALIGNED;
 	}