tcp: do not pass timestamp to tcp_rack_advance()

No longer needed, since tp->tcp_mstamp holds the information.

This is needed to remove sack_state.ack_time in a following patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -1855,8 +1855,7 @@ void tcp_init(void);
 /* tcp_recovery.c */
 extern void tcp_rack_mark_lost(struct sock *sk);
 extern void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
-			     const struct skb_mstamp *xmit_time,
-			     const struct skb_mstamp *ack_time);
+			     const struct skb_mstamp *xmit_time);
 extern void tcp_rack_reo_timeout(struct sock *sk);
 
 /*

net/ipv4/tcp_input.c

@@ -1214,8 +1214,7 @@ static u8 tcp_sacktag_one(struct sock *sk,
 		return sacked;
 
 	if (!(sacked & TCPCB_SACKED_ACKED)) {
-		tcp_rack_advance(tp, sacked, end_seq,
-				 xmit_time, &state->ack_time);
+		tcp_rack_advance(tp, sacked, end_seq, xmit_time);
 
 		if (sacked & TCPCB_SACKED_RETRANS) {
 			/* If the segment is not tagged as lost,
@@ -3118,8 +3117,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets,
 			tp->delivered += acked_pcount;
 			if (!tcp_skb_spurious_retrans(tp, skb))
 				tcp_rack_advance(tp, sacked, scb->end_seq,
-						 &skb->skb_mstamp,
-						 &sack->ack_time);
+						 &skb->skb_mstamp);
 		}
 		if (sacked & TCPCB_LOST)
 			tp->lost_out -= acked_pcount;

net/ipv4/tcp_recovery.c

@@ -127,8 +127,7 @@ void tcp_rack_mark_lost(struct sock *sk)
  * draft-cheng-tcpm-rack-00.txt
  */
 void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
-		      const struct skb_mstamp *xmit_time,
-		      const struct skb_mstamp *ack_time)
+		      const struct skb_mstamp *xmit_time)
 {
 	u32 rtt_us;
 
@@ -137,7 +136,7 @@ void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
 				 end_seq, tp->rack.end_seq))
 		return;
 
-	rtt_us = skb_mstamp_us_delta(ack_time, xmit_time);
+	rtt_us = skb_mstamp_us_delta(&tp->tcp_mstamp, xmit_time);
 	if (sacked & TCPCB_RETRANS) {
 		/* If the sacked packet was retransmitted, it's ambiguous
 		 * whether the retransmission or the original (or the prior