Merge branch 'tcp-redundant-checks'

Soheil Hassas Yeganeh says:

====================
tcp: simplify ack tx timestamps

v2:
- Fully remove SKBTX_ACK_TSTAMP, as suggested by Willem de Bruijn.

This patch series aims at removing redundant checks and fields
for ack timestamps for TCP.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 6 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b1b2045ac3a9..b3a31b4df57c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1111,11 +1111,17 @@ static void tcp_adjust_pcount(struct sock *sk, const struct sk_buff *skb, int de
 	tcp_verify_left_out(tp);
 }
 
+static bool tcp_has_tx_tstamp(const struct sk_buff *skb)
+{
+	return TCP_SKB_CB(skb)->txstamp_ack ||
+		(skb_shinfo(skb)->tx_flags & SKBTX_ANY_TSTAMP);
+}
+
 static void tcp_fragment_tstamp(struct sk_buff *skb, struct sk_buff *skb2)
 {
 	struct skb_shared_info *shinfo = skb_shinfo(skb);
 
-	if (unlikely(shinfo->tx_flags & SKBTX_ANY_TSTAMP) &&
+	if (unlikely(tcp_has_tx_tstamp(skb)) &&
 	    !before(shinfo->tskey, TCP_SKB_CB(skb2)->seq)) {
 		struct skb_shared_info *shinfo2 = skb_shinfo(skb2);
 		u8 tsflags = shinfo->tx_flags & SKBTX_ANY_TSTAMP;
@@ -2446,13 +2452,12 @@ u32 __tcp_select_window(struct sock *sk)
 void tcp_skb_collapse_tstamp(struct sk_buff *skb,
 			     const struct sk_buff *next_skb)
 {
-	const struct skb_shared_info *next_shinfo = skb_shinfo(next_skb);
-	u8 tsflags = next_shinfo->tx_flags & SKBTX_ANY_TSTAMP;
-
-	if (unlikely(tsflags)) {
+	if (unlikely(tcp_has_tx_tstamp(next_skb))) {
+		const struct skb_shared_info *next_shinfo =
+			skb_shinfo(next_skb);
 		struct skb_shared_info *shinfo = skb_shinfo(skb);
 
-		shinfo->tx_flags |= tsflags;
+		shinfo->tx_flags |= next_shinfo->tx_flags & SKBTX_ANY_TSTAMP;
 		shinfo->tskey = next_shinfo->tskey;
 		TCP_SKB_CB(skb)->txstamp_ack |=
 			TCP_SKB_CB(next_skb)->txstamp_ack;