From 0a2cf20c3fb62ad4717276b5303bf831f7b29d54 Mon Sep 17 00:00:00 2001 From: Soheil Hassas Yeganeh Date: Wed, 27 Apr 2016 23:39:01 -0400 Subject: tcp: remove SKBTX_ACK_TSTAMP since it is redundant The SKBTX_ACK_TSTAMP flag is set in skb_shinfo->tx_flags when the timestamp of the TCP acknowledgement should be reported on error queue. Since accessing skb_shinfo is likely to incur a cache-line miss at the time of receiving the ack, the txstamp_ack bit was added in tcp_skb_cb, which is set iff the SKBTX_ACK_TSTAMP flag is set for an skb. This makes SKBTX_ACK_TSTAMP flag redundant. Remove the SKBTX_ACK_TSTAMP and instead use the txstamp_ack bit everywhere. Note that this frees one bit in shinfo->tx_flags. Signed-off-by: Soheil Hassas Yeganeh Acked-by: Martin KaFai Lau Suggested-by: Willem de Bruijn Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 0d5239c283cb..70c370b93762 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3087,8 +3087,7 @@ static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb, return; shinfo = skb_shinfo(skb); - if ((shinfo->tx_flags & SKBTX_ACK_TSTAMP) && - !before(shinfo->tskey, prior_snd_una) && + if (!before(shinfo->tskey, prior_snd_una) && before(shinfo->tskey, tcp_sk(sk)->snd_una)) __skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK); } -- cgit v1.2.2