From 30a3ae30c775e2723f86ef70746ad3cb4404a4c9 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 26 May 2009 18:50:26 +0000
Subject: [PATCH] tcp: Optimise len/mss comparison
Instead of checking len > mss || len == 0, we can accomplish
both by checking (len - 1) > mss using the unsigned wraparound.
At nearly a million times a second, this might just help.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 313960e4cfdc..68342d431896 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2566,7 +2566,7 @@ found:
mss = skb_shinfo(p)->gso_size;
- flush |= (len > mss) | !len;
+ flush |= (len - 1) >= mss;
flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
if (flush || skb_gro_receive(head, skb)) {
--
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