From: Eric Dumazet <eduma...@google.com>
While chasing tcp_xmit_retransmit_queue() kasan issue, I found
that we could avoid reading sacked field of skb that we wont send,
possibly removing one cache line miss.
Very minor change in slow path, but why not ? ;)
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
net/ipv4/tcp_output.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index
bdaef7fd6e47701b2d2280e1f40f816e1920c432..8b45794eb6b2600c914e504b8031f61dbbe164a3
100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2776,7 +2776,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
max_segs = tcp_tso_autosize(sk, tcp_current_mss(sk));
tcp_for_write_queue_from(skb, sk) {
- __u8 sacked = TCP_SKB_CB(skb)->sacked;
+ __u8 sacked;
int segs;
if (skb == tcp_send_head(sk))
@@ -2788,6 +2788,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
segs = tp->snd_cwnd - tcp_packets_in_flight(tp);
if (segs <= 0)
return;
+ sacked = TCP_SKB_CB(skb)->sacked;
/* In case tcp_shift_skb_data() have aggregated large skbs,
* we need to make sure not sending too bigs TSO packets
*/
