* [TCP] Avoid a divide in tcp_mtu_probing()
@ 2007-12-21 13:32 Eric Dumazet
2007-12-21 13:58 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Eric Dumazet @ 2007-12-21 13:32 UTC (permalink / raw)
To: David Miller; +Cc: netdev@vger.kernel.org
tcp_mtu_to_mss() being signed, compiler might emit an integer divide
to compute tcp_mtu_to_mss()/2 .
Using a right shift is OK here and less expensive.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index ea111e9..ea85bc0 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -125,7 +125,7 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
int mss;
- mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low)/2;
+ mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
mss = min(sysctl_tcp_base_mss, mss);
mss = max(mss, 68 - tp->tcp_header_len);
icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
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