[TCP]: Avoid two divides in __tcp_grow_window()

tcp_win_from_space() being signed, compiler might emit an integer divide
to compute tcp_win_from_space()/2 .

Using right shifts is OK here and less expensive.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index bc2d5f70966e..519bd24e0d3b 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -289,8 +289,8 @@ static int __tcp_grow_window(const struct sock *sk, const struct sk_buff *skb)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         /* Optimize this! */
-        int truesize = tcp_win_from_space(skb->truesize)/2;
-        int window = tcp_win_from_space(sysctl_tcp_rmem[2])/2;
+        int truesize = tcp_win_from_space(skb->truesize) >> 1;
+        int window = tcp_win_from_space(sysctl_tcp_rmem[2]) >> 1;
 
         while (tp->rcv_ssthresh <= window) {
                 if (truesize <= skb->len)