tcp: tcp_tso_segment() small optimization

We can move th->check computation out of the loop, as compiler
doesn't know each skb initially share same tcp headers after
skb_segment()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2013-04-13 03:22:08 +00:00 committed by David S. Miller
parent eb1d064058
commit bece1b9708

View File

@ -2886,6 +2886,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
unsigned int oldlen;
unsigned int mss;
struct sk_buff *gso_skb = skb;
__sum16 newcheck;
if (!pskb_may_pull(skb, sizeof(*th)))
goto out;
@ -2936,11 +2937,13 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
th = tcp_hdr(skb);
seq = ntohl(th->seq);
newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
do {
th->fin = th->psh = 0;
th->check = newcheck;
th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
(__force u32)delta));
if (skb->ip_summed != CHECKSUM_PARTIAL)
th->check =
csum_fold(csum_partial(skb_transport_header(skb),