Merge branch 'tcp-TCP-TS-option-use-1-ms-clock'

Eric Dumazet says:

====================
tcp: TCP TS option use 1 ms clock

TCP Timestamps option is defined in RFC 7323

Traditionally on linux, it has been tied to the internal
'jiffy' variable, because it had been a cheap and good enough
generator.

Unfortunately some distros use HZ=250 or even HZ=100 leading
to not very useful TCP timestamps.

For TCP flows in the DC, Google has used usec resolution for more
than two years with great success [1].
RCVBUF autotuning is more precise.

This series converts tp->tcp_mstamp to a plain u64 value storing
a 1 usec TCP clock.

This choice will allow us to upstream the 1 usec TS option as
discussed in IETF 97.

Kathleen Nichols [2] and others advocate for 1ms TS clocks for
network analysis. (1ms being the lowest value supported by RFC 7323.)

[1] https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf
[2] http://netseminar.stanford.edu/seminars/02_02_17.pdf
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -506,66 +506,6 @@ typedef unsigned int sk_buff_data_t;
 typedef unsigned char *sk_buff_data_t;
 #endif
 
-/**
- * struct skb_mstamp - multi resolution time stamps
- * @stamp_us: timestamp in us resolution
- * @stamp_jiffies: timestamp in jiffies
- */
-struct skb_mstamp {
-	union {
-		u64		v64;
-		struct {
-			u32	stamp_us;
-			u32	stamp_jiffies;
-		};
-	};
-};
-
-/**
- * skb_mstamp_get - get current timestamp
- * @cl: place to store timestamps
- */
-static inline void skb_mstamp_get(struct skb_mstamp *cl)
-{
-	u64 val = local_clock();
-
-	do_div(val, NSEC_PER_USEC);
-	cl->stamp_us = (u32)val;
-	cl->stamp_jiffies = (u32)jiffies;
-}
-
-/**
- * skb_mstamp_delta - compute the difference in usec between two skb_mstamp
- * @t1: pointer to newest sample
- * @t0: pointer to oldest sample
- */
-static inline u32 skb_mstamp_us_delta(const struct skb_mstamp *t1,
-				      const struct skb_mstamp *t0)
-{
-	s32 delta_us = t1->stamp_us - t0->stamp_us;
-	u32 delta_jiffies = t1->stamp_jiffies - t0->stamp_jiffies;
-
-	/* If delta_us is negative, this might be because interval is too big,
-	 * or local_clock() drift is too big : fallback using jiffies.
-	 */
-	if (delta_us <= 0 ||
-	    delta_jiffies >= (INT_MAX / (USEC_PER_SEC / HZ)))
-
-		delta_us = jiffies_to_usecs(delta_jiffies);
-
-	return delta_us;
-}
-
-static inline bool skb_mstamp_after(const struct skb_mstamp *t1,
-				    const struct skb_mstamp *t0)
-{
-	s32 diff = t1->stamp_jiffies - t0->stamp_jiffies;
-
-	if (!diff)
-		diff = t1->stamp_us - t0->stamp_us;
-	return diff > 0;
-}
-
 /** 
  *	struct sk_buff - socket buffer
  *	@next: Next buffer in list
@@ -646,7 +586,7 @@ struct sk_buff {
 
 			union {
 				ktime_t		tstamp;
-				struct skb_mstamp skb_mstamp;
+				u64		skb_mstamp;
 			};
 		};
 		struct rb_node	rbnode; /* used in netem & tcp stack */

include/linux/tcp.h

@@ -123,7 +123,7 @@ struct tcp_request_sock_ops;
 struct tcp_request_sock {
 	struct inet_request_sock 	req;
 	const struct tcp_request_sock_ops *af_specific;
-	struct skb_mstamp		snt_synack; /* first SYNACK sent time */
+	u64				snt_synack; /* first SYNACK sent time */
 	bool				tfo_listener;
 	u32				txhash;
 	u32				rcv_isn;
@@ -211,7 +211,7 @@ struct tcp_sock {
 
 	/* Information of the most recently (s)acked skb */
 	struct tcp_rack {
-		struct skb_mstamp mstamp; /* (Re)sent time of the skb */
+		u64 mstamp; /* (Re)sent time of the skb */
 		u32 rtt_us;  /* Associated RTT */
 		u32 end_seq; /* Ending TCP sequence of the skb */
 		u8 advanced; /* mstamp advanced since last lost marking */
@@ -240,7 +240,7 @@ struct tcp_sock {
 	u32	tlp_high_seq;	/* snd_nxt at the time of TLP retransmit. */
 
 /* RTT measurement */
-	struct skb_mstamp tcp_mstamp; /* most recent packet received/sent */
+	u64	tcp_mstamp;	/* most recent packet received/sent */
 	u32	srtt_us;	/* smoothed round trip time << 3 in usecs */
 	u32	mdev_us;	/* medium deviation			*/
 	u32	mdev_max_us;	/* maximal mdev for the last rtt period	*/
@@ -280,8 +280,8 @@ struct tcp_sock {
 	u32	delivered;	/* Total data packets delivered incl. rexmits */
 	u32	lost;		/* Total data packets lost incl. rexmits */
 	u32	app_limited;	/* limited until "delivered" reaches this val */
-	struct skb_mstamp first_tx_mstamp;  /* start of window send phase */
-	struct skb_mstamp delivered_mstamp; /* time we reached "delivered" */
+	u64	first_tx_mstamp;  /* start of window send phase */
+	u64	delivered_mstamp; /* time we reached "delivered" */
 	u32	rate_delivered;    /* saved rate sample: packets delivered */
 	u32	rate_interval_us;  /* saved rate sample: time elapsed */
 
@@ -337,14 +337,14 @@ struct tcp_sock {
 	struct {
 		u32	rtt_us;
 		u32	seq;
-		struct skb_mstamp time;
+		u64	time;
 	} rcv_rtt_est;
 
 /* Receiver queue space */
 	struct {
 		int	space;
 		u32	seq;
-		struct skb_mstamp time;
+		u64	time;
 	} rcvq_space;
 
 /* TCP-specific MTU probe information. */

include/net/tcp.h

@@ -519,7 +519,7 @@ static inline u32 tcp_cookie_time(void)
 u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th,
 			      u16 *mssp);
 __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss);
-__u32 cookie_init_timestamp(struct request_sock *req);
+u64 cookie_init_timestamp(struct request_sock *req);
 bool cookie_timestamp_decode(struct tcp_options_received *opt);
 bool cookie_ecn_ok(const struct tcp_options_received *opt,
 		   const struct net *net, const struct dst_entry *dst);
@@ -700,17 +700,61 @@ u32 __tcp_select_window(struct sock *sk);
 
 void tcp_send_window_probe(struct sock *sk);
 
-/* TCP timestamps are only 32-bits, this causes a slight
- * complication on 64-bit systems since we store a snapshot
- * of jiffies in the buffer control blocks below.  We decided
- * to use only the low 32-bits of jiffies and hide the ugly
- * casts with the following macro.
+/* TCP uses 32bit jiffies to save some space.
+ * Note that this is different from tcp_time_stamp, which
+ * historically has been the same until linux-4.13.
  */
-#define tcp_time_stamp		((__u32)(jiffies))
+#define tcp_jiffies32 ((u32)jiffies)
+
+/*
+ * Deliver a 32bit value for TCP timestamp option (RFC 7323)
+ * It is no longer tied to jiffies, but to 1 ms clock.
+ * Note: double check if you want to use tcp_jiffies32 instead of this.
+ */
+#define TCP_TS_HZ	1000
+
+static inline u64 tcp_clock_ns(void)
+{
+	return local_clock();
+}
+
+static inline u64 tcp_clock_us(void)
+{
+	return div_u64(tcp_clock_ns(), NSEC_PER_USEC);
+}
+
+/* This should only be used in contexts where tp->tcp_mstamp is up to date */
+static inline u32 tcp_time_stamp(const struct tcp_sock *tp)
+{
+	return div_u64(tp->tcp_mstamp, USEC_PER_SEC / TCP_TS_HZ);
+}
+
+/* Could use tcp_clock_us() / 1000, but this version uses a single divide */
+static inline u32 tcp_time_stamp_raw(void)
+{
+	return div_u64(tcp_clock_ns(), NSEC_PER_SEC / TCP_TS_HZ);
+}
+
+
+/* Refresh 1us clock of a TCP socket,
+ * ensuring monotically increasing values.
+ */
+static inline void tcp_mstamp_refresh(struct tcp_sock *tp)
+{
+	u64 val = tcp_clock_us();
+
+	if (val > tp->tcp_mstamp)
+		tp->tcp_mstamp = val;
+}
+
+static inline u32 tcp_stamp_us_delta(u64 t1, u64 t0)
+{
+	return max_t(s64, t1 - t0, 0);
+}
 
 static inline u32 tcp_skb_timestamp(const struct sk_buff *skb)
 {
-	return skb->skb_mstamp.stamp_jiffies;
+	return div_u64(skb->skb_mstamp, USEC_PER_SEC / TCP_TS_HZ);
 }
 
 
@@ -775,9 +819,9 @@ struct tcp_skb_cb {
 			/* pkts S/ACKed so far upon tx of skb, incl retrans: */
 			__u32 delivered;
 			/* start of send pipeline phase */
-			struct skb_mstamp first_tx_mstamp;
+			u64 first_tx_mstamp;
 			/* when we reached the "delivered" count */
-			struct skb_mstamp delivered_mstamp;
+			u64 delivered_mstamp;
 		} tx;   /* only used for outgoing skbs */
 		union {
 			struct inet_skb_parm	h4;
@@ -893,7 +937,7 @@ struct ack_sample {
  * A sample is invalid if "delivered" or "interval_us" is negative.
  */
 struct rate_sample {
-	struct	skb_mstamp prior_mstamp; /* starting timestamp for interval */
+	u64  prior_mstamp; /* starting timestamp for interval */
 	u32  prior_delivered;	/* tp->delivered at "prior_mstamp" */
 	s32  delivered;		/* number of packets delivered over interval */
 	long interval_us;	/* time for tp->delivered to incr "delivered" */
@@ -1242,7 +1286,7 @@ static inline void tcp_slow_start_after_idle_check(struct sock *sk)
 	if (!sysctl_tcp_slow_start_after_idle || tp->packets_out ||
 	    ca_ops->cong_control)
 		return;
-	delta = tcp_time_stamp - tp->lsndtime;
+	delta = tcp_jiffies32 - tp->lsndtime;
 	if (delta > inet_csk(sk)->icsk_rto)
 		tcp_cwnd_restart(sk, delta);
 }
@@ -1304,8 +1348,8 @@ static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
 {
 	const struct inet_connection_sock *icsk = &tp->inet_conn;
 
-	return min_t(u32, tcp_time_stamp - icsk->icsk_ack.lrcvtime,
-			  tcp_time_stamp - tp->rcv_tstamp);
+	return min_t(u32, tcp_jiffies32 - icsk->icsk_ack.lrcvtime,
+			  tcp_jiffies32 - tp->rcv_tstamp);
 }
 
 static inline int tcp_fin_time(const struct sock *sk)
@@ -1859,7 +1903,7 @@ 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);
+			     u64 xmit_time);
 extern void tcp_rack_reo_timeout(struct sock *sk);
 
 /*

net/dccp/ccids/ccid2.c

@@ -233,7 +233,7 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
 {
 	struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-	const u32 now = ccid2_time_stamp;
+	const u32 now = ccid2_jiffies32;
 	struct ccid2_seq *next;
 
 	/* slow-start after idle periods (RFC 2581, RFC 2861) */
@@ -466,7 +466,7 @@ static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp,
 	 * The cleanest solution is to not use the ccid2s_sent field at all
 	 * and instead use DCCP timestamps: requires changes in other places.
 	 */
-	ccid2_rtt_estimator(sk, ccid2_time_stamp - seqp->ccid2s_sent);
+	ccid2_rtt_estimator(sk, ccid2_jiffies32 - seqp->ccid2s_sent);
 }
 
 static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
@@ -478,7 +478,7 @@ static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
 		return;
 	}
 
-	hc->tx_last_cong = ccid2_time_stamp;
+	hc->tx_last_cong = ccid2_jiffies32;
 
 	hc->tx_cwnd      = hc->tx_cwnd / 2 ? : 1U;
 	hc->tx_ssthresh  = max(hc->tx_cwnd, 2U);
@@ -731,7 +731,7 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
 
 	hc->tx_rto	 = DCCP_TIMEOUT_INIT;
 	hc->tx_rpdupack  = -1;
-	hc->tx_last_cong = hc->tx_lsndtime = hc->tx_cwnd_stamp = ccid2_time_stamp;
+	hc->tx_last_cong = hc->tx_lsndtime = hc->tx_cwnd_stamp = ccid2_jiffies32;
 	hc->tx_cwnd_used = 0;
 	setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire,
 			(unsigned long)sk);

net/dccp/ccids/ccid2.h

@@ -27,7 +27,7 @@
  * CCID-2 timestamping faces the same issues as TCP timestamping.
  * Hence we reuse/share as much of the code as possible.
  */
-#define ccid2_time_stamp	tcp_time_stamp
+#define ccid2_jiffies32	((u32)jiffies)
 
 /* NUMDUPACK parameter from RFC 4341, p. 6 */
 #define NUMDUPACK	3

net/ipv4/syncookies.c

@@ -66,10 +66,10 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
  * Since subsequent timestamps use the normal tcp_time_stamp value, we
  * must make sure that the resulting initial timestamp is <= tcp_time_stamp.
  */
-__u32 cookie_init_timestamp(struct request_sock *req)
+u64 cookie_init_timestamp(struct request_sock *req)
 {
 	struct inet_request_sock *ireq;
-	u32 ts, ts_now = tcp_time_stamp;
+	u32 ts, ts_now = tcp_time_stamp_raw();
 	u32 options = 0;
 
 	ireq = inet_rsk(req);
@@ -88,7 +88,7 @@ __u32 cookie_init_timestamp(struct request_sock *req)
 		ts <<= TSBITS;
 		ts |= options;
 	}
-	return ts;
+	return (u64)ts * (USEC_PER_SEC / TCP_TS_HZ);
 }
 
 
@@ -343,7 +343,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 	ireq->wscale_ok		= tcp_opt.wscale_ok;
 	ireq->tstamp_ok		= tcp_opt.saw_tstamp;
 	req->ts_recent		= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
-	treq->snt_synack.v64	= 0;
+	treq->snt_synack	= 0;
 	treq->tfo_listener	= false;
 
 	ireq->ir_iif = inet_request_bound_dev_if(sk, skb);

net/ipv4/tcp.c

@@ -386,7 +386,7 @@ void tcp_init_sock(struct sock *sk)
 
 	icsk->icsk_rto = TCP_TIMEOUT_INIT;
 	tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
-	minmax_reset(&tp->rtt_min, tcp_time_stamp, ~0U);
+	minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U);
 
 	/* So many TCP implementations out there (incorrectly) count the
 	 * initial SYN frame in their delayed-ACK and congestion control
@@ -2706,7 +2706,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
 		if (!tp->repair)
 			err = -EPERM;
 		else
-			tp->tsoffset = val - tcp_time_stamp;
+			tp->tsoffset = val - tcp_time_stamp_raw();
 		break;
 	case TCP_REPAIR_WINDOW:
 		err = tcp_repair_set_window(tp, optval, optlen);
@@ -2757,7 +2757,7 @@ static void tcp_get_info_chrono_stats(const struct tcp_sock *tp,
 	for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) {
 		stats[i] = tp->chrono_stat[i - 1];
 		if (i == tp->chrono_type)
-			stats[i] += tcp_time_stamp - tp->chrono_start;
+			stats[i] += tcp_jiffies32 - tp->chrono_start;
 		stats[i] *= USEC_PER_SEC / HZ;
 		total += stats[i];
 	}
@@ -2841,7 +2841,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
 	info->tcpi_retrans = tp->retrans_out;
 	info->tcpi_fackets = tp->fackets_out;
 
-	now = tcp_time_stamp;
+	now = tcp_jiffies32;
 	info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
 	info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
 	info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
@@ -3072,7 +3072,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
 		break;
 
 	case TCP_TIMESTAMP:
-		val = tcp_time_stamp + tp->tsoffset;
+		val = tcp_time_stamp_raw() + tp->tsoffset;
 		break;
 	case TCP_NOTSENT_LOWAT:
 		val = tp->notsent_lowat;

net/ipv4/tcp_bbr.c

@@ -91,7 +91,7 @@ struct bbr {
 	struct minmax bw;	/* Max recent delivery rate in pkts/uS << 24 */
 	u32	rtt_cnt;	    /* count of packet-timed rounds elapsed */
 	u32     next_rtt_delivered; /* scb->tx.delivered at end of round */
-	struct skb_mstamp cycle_mstamp;  /* time of this cycle phase start */
+	u64	cycle_mstamp;	     /* time of this cycle phase start */
 	u32     mode:3,		     /* current bbr_mode in state machine */
 		prev_ca_state:3,     /* CA state on previous ACK */
 		packet_conservation:1,  /* use packet conservation? */
@@ -411,7 +411,7 @@ static bool bbr_is_next_cycle_phase(struct sock *sk,
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct bbr *bbr = inet_csk_ca(sk);
 	bool is_full_length =
-		skb_mstamp_us_delta(&tp->delivered_mstamp, &bbr->cycle_mstamp) >
+		tcp_stamp_us_delta(tp->delivered_mstamp, bbr->cycle_mstamp) >
 		bbr->min_rtt_us;
 	u32 inflight, bw;
 
@@ -497,7 +497,7 @@ static void bbr_reset_lt_bw_sampling_interval(struct sock *sk)
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct bbr *bbr = inet_csk_ca(sk);
 
-	bbr->lt_last_stamp = tp->delivered_mstamp.stamp_jiffies;
+	bbr->lt_last_stamp = div_u64(tp->delivered_mstamp, USEC_PER_MSEC);
 	bbr->lt_last_delivered = tp->delivered;
 	bbr->lt_last_lost = tp->lost;
 	bbr->lt_rtt_cnt = 0;
@@ -551,7 +551,7 @@ static void bbr_lt_bw_sampling(struct sock *sk, const struct rate_sample *rs)
 	struct bbr *bbr = inet_csk_ca(sk);
 	u32 lost, delivered;
 	u64 bw;
-	s32 t;
+	u32 t;
 
 	if (bbr->lt_use_bw) {	/* already using long-term rate, lt_bw? */
 		if (bbr->mode == BBR_PROBE_BW && bbr->round_start &&
@@ -603,15 +603,15 @@ static void bbr_lt_bw_sampling(struct sock *sk, const struct rate_sample *rs)
 		return;
 
 	/* Find average delivery rate in this sampling interval. */
-	t = (s32)(tp->delivered_mstamp.stamp_jiffies - bbr->lt_last_stamp);
-	if (t < 1)
-		return;		/* interval is less than one jiffy, so wait */
-	t = jiffies_to_usecs(t);
-	/* Interval long enough for jiffies_to_usecs() to return a bogus 0? */
-	if (t < 1) {
+	t = div_u64(tp->delivered_mstamp, USEC_PER_MSEC) - bbr->lt_last_stamp;
+	if ((s32)t < 1)
+		return;		/* interval is less than one ms, so wait */
+	/* Check if can multiply without overflow */
+	if (t >= ~0U / USEC_PER_MSEC) {
 		bbr_reset_lt_bw_sampling(sk);  /* interval too long; reset */
 		return;
 	}
+	t *= USEC_PER_MSEC;
 	bw = (u64)delivered * BW_UNIT;
 	do_div(bw, t);
 	bbr_lt_bw_interval_done(sk, bw);
@@ -730,12 +730,12 @@ static void bbr_update_min_rtt(struct sock *sk, const struct rate_sample *rs)
 	bool filter_expired;
 
 	/* Track min RTT seen in the min_rtt_win_sec filter window: */
-	filter_expired = after(tcp_time_stamp,
+	filter_expired = after(tcp_jiffies32,
 			       bbr->min_rtt_stamp + bbr_min_rtt_win_sec * HZ);
 	if (rs->rtt_us >= 0 &&
 	    (rs->rtt_us <= bbr->min_rtt_us || filter_expired)) {
 		bbr->min_rtt_us = rs->rtt_us;
-		bbr->min_rtt_stamp = tcp_time_stamp;
+		bbr->min_rtt_stamp = tcp_jiffies32;
 	}
 
 	if (bbr_probe_rtt_mode_ms > 0 && filter_expired &&
@@ -754,7 +754,7 @@ static void bbr_update_min_rtt(struct sock *sk, const struct rate_sample *rs)
 		/* Maintain min packets in flight for max(200 ms, 1 round). */
 		if (!bbr->probe_rtt_done_stamp &&
 		    tcp_packets_in_flight(tp) <= bbr_cwnd_min_target) {
-			bbr->probe_rtt_done_stamp = tcp_time_stamp +
+			bbr->probe_rtt_done_stamp = tcp_jiffies32 +
 				msecs_to_jiffies(bbr_probe_rtt_mode_ms);
 			bbr->probe_rtt_round_done = 0;
 			bbr->next_rtt_delivered = tp->delivered;
@@ -762,8 +762,8 @@ static void bbr_update_min_rtt(struct sock *sk, const struct rate_sample *rs)
 			if (bbr->round_start)
 				bbr->probe_rtt_round_done = 1;
 			if (bbr->probe_rtt_round_done &&
-			    after(tcp_time_stamp, bbr->probe_rtt_done_stamp)) {
-				bbr->min_rtt_stamp = tcp_time_stamp;
+			    after(tcp_jiffies32, bbr->probe_rtt_done_stamp)) {
+				bbr->min_rtt_stamp = tcp_jiffies32;
 				bbr->restore_cwnd = 1;  /* snap to prior_cwnd */
 				bbr_reset_mode(sk);
 			}
@@ -810,7 +810,7 @@ static void bbr_init(struct sock *sk)
 	bbr->probe_rtt_done_stamp = 0;
 	bbr->probe_rtt_round_done = 0;
 	bbr->min_rtt_us = tcp_min_rtt(tp);
-	bbr->min_rtt_stamp = tcp_time_stamp;
+	bbr->min_rtt_stamp = tcp_jiffies32;
 
 	minmax_reset(&bbr->bw, bbr->rtt_cnt, 0);  /* init max bw to 0 */
 
@@ -825,7 +825,7 @@ static void bbr_init(struct sock *sk)
 	bbr->idle_restart = 0;
 	bbr->full_bw = 0;
 	bbr->full_bw_cnt = 0;
-	bbr->cycle_mstamp.v64 = 0;
+	bbr->cycle_mstamp = 0;
 	bbr->cycle_idx = 0;
 	bbr_reset_lt_bw_sampling(sk);
 	bbr_reset_startup_mode(sk);

net/ipv4/tcp_bic.c

@@ -84,14 +84,14 @@ static void bictcp_init(struct sock *sk)
 static inline void bictcp_update(struct bictcp *ca, u32 cwnd)
 {
 	if (ca->last_cwnd == cwnd &&
-	    (s32)(tcp_time_stamp - ca->last_time) <= HZ / 32)
+	    (s32)(tcp_jiffies32 - ca->last_time) <= HZ / 32)
 		return;
 
 	ca->last_cwnd = cwnd;
-	ca->last_time = tcp_time_stamp;
+	ca->last_time = tcp_jiffies32;
 
 	if (ca->epoch_start == 0) /* record the beginning of an epoch */
-		ca->epoch_start = tcp_time_stamp;
+		ca->epoch_start = tcp_jiffies32;
 
 	/* start off normal */
 	if (cwnd <= low_window) {

net/ipv4/tcp_cubic.c

@@ -155,7 +155,7 @@ static void bictcp_cwnd_event(struct sock *sk, enum tcp_ca_event event)
 {
 	if (event == CA_EVENT_TX_START) {
 		struct bictcp *ca = inet_csk_ca(sk);
-		u32 now = tcp_time_stamp;
+		u32 now = tcp_jiffies32;
 		s32 delta;
 
 		delta = now - tcp_sk(sk)->lsndtime;
@@ -231,21 +231,21 @@ static inline void bictcp_update(struct bictcp *ca, u32 cwnd, u32 acked)
 	ca->ack_cnt += acked;	/* count the number of ACKed packets */
 
 	if (ca->last_cwnd == cwnd &&
-	    (s32)(tcp_time_stamp - ca->last_time) <= HZ / 32)
+	    (s32)(tcp_jiffies32 - ca->last_time) <= HZ / 32)
 		return;
 
 	/* The CUBIC function can update ca->cnt at most once per jiffy.
 	 * On all cwnd reduction events, ca->epoch_start is set to 0,
 	 * which will force a recalculation of ca->cnt.
 	 */
-	if (ca->epoch_start && tcp_time_stamp == ca->last_time)
+	if (ca->epoch_start && tcp_jiffies32 == ca->last_time)
 		goto tcp_friendliness;
 
 	ca->last_cwnd = cwnd;
-	ca->last_time = tcp_time_stamp;
+	ca->last_time = tcp_jiffies32;
 
 	if (ca->epoch_start == 0) {
-		ca->epoch_start = tcp_time_stamp;	/* record beginning */
+		ca->epoch_start = tcp_jiffies32;	/* record beginning */
 		ca->ack_cnt = acked;			/* start counting */
 		ca->tcp_cwnd = cwnd;			/* syn with cubic */
 
@@ -276,7 +276,7 @@ static inline void bictcp_update(struct bictcp *ca, u32 cwnd, u32 acked)
 	 * if the cwnd < 1 million packets !!!
 	 */
 
-	t = (s32)(tcp_time_stamp - ca->epoch_start);
+	t = (s32)(tcp_jiffies32 - ca->epoch_start);
 	t += msecs_to_jiffies(ca->delay_min >> 3);
 	/* change the unit from HZ to bictcp_HZ */
 	t <<= BICTCP_HZ;
@@ -448,7 +448,7 @@ static void bictcp_acked(struct sock *sk, const struct ack_sample *sample)
 		return;
 
 	/* Discard delay samples right after fast recovery */
-	if (ca->epoch_start && (s32)(tcp_time_stamp - ca->epoch_start) < HZ)
+	if (ca->epoch_start && (s32)(tcp_jiffies32 - ca->epoch_start) < HZ)
 		return;
 
 	delay = (sample->rtt_us << 3) / USEC_PER_MSEC;

net/ipv4/tcp_htcp.c

@@ -104,7 +104,7 @@ static void measure_achieved_throughput(struct sock *sk,
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	const struct tcp_sock *tp = tcp_sk(sk);
 	struct htcp *ca = inet_csk_ca(sk);
-	u32 now = tcp_time_stamp;
+	u32 now = tcp_jiffies32;
 
 	if (icsk->icsk_ca_state == TCP_CA_Open)
 		ca->pkts_acked = sample->pkts_acked;

net/ipv4/tcp_ipv4.c

@@ -376,8 +376,9 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 	struct sock *sk;
 	struct sk_buff *skb;
 	struct request_sock *fastopen;
-	__u32 seq, snd_una;
-	__u32 remaining;
+	u32 seq, snd_una;
+	s32 remaining;
+	u32 delta_us;
 	int err;
 	struct net *net = dev_net(icmp_skb->dev);
 
@@ -483,11 +484,12 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 		skb = tcp_write_queue_head(sk);
 		BUG_ON(!skb);
 
+		tcp_mstamp_refresh(tp);
+		delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp);
 		remaining = icsk->icsk_rto -
-			    min(icsk->icsk_rto,
-				tcp_time_stamp - tcp_skb_timestamp(skb));
+			    usecs_to_jiffies(delta_us);
 
-		if (remaining) {
+		if (remaining > 0) {
 			inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
 						  remaining, TCP_RTO_MAX);
 		} else {
@@ -811,7 +813,7 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
 	tcp_v4_send_ack(sk, skb,
 			tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
-			tcp_time_stamp + tcptw->tw_ts_offset,
+			tcp_time_stamp_raw() + tcptw->tw_ts_offset,
 			tcptw->tw_ts_recent,
 			tw->tw_bound_dev_if,
 			tcp_twsk_md5_key(tcptw),
@@ -839,7 +841,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 	tcp_v4_send_ack(sk, skb, seq,
 			tcp_rsk(req)->rcv_nxt,
 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
-			tcp_time_stamp + tcp_rsk(req)->ts_off,
+			tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
 			req->ts_recent,
 			0,
 			tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,

net/ipv4/tcp_lp.c

@@ -37,7 +37,7 @@
 #include <net/tcp.h>
 
 /* resolution of owd */
-#define LP_RESOL       1000
+#define LP_RESOL       TCP_TS_HZ
 
 /**
  * enum tcp_lp_state
@@ -147,9 +147,9 @@ static u32 tcp_lp_remote_hz_estimator(struct sock *sk)
 	    tp->rx_opt.rcv_tsecr == lp->local_ref_time)
 		goto out;
 
-	m = HZ * (tp->rx_opt.rcv_tsval -
-		  lp->remote_ref_time) / (tp->rx_opt.rcv_tsecr -
-					  lp->local_ref_time);
+	m = TCP_TS_HZ *
+	    (tp->rx_opt.rcv_tsval - lp->remote_ref_time) /
+	    (tp->rx_opt.rcv_tsecr - lp->local_ref_time);
 	if (m < 0)
 		m = -m;
 
@@ -194,7 +194,7 @@ static u32 tcp_lp_owd_calculator(struct sock *sk)
 	if (lp->flag & LP_VALID_RHZ) {
 		owd =
 		    tp->rx_opt.rcv_tsval * (LP_RESOL / lp->remote_hz) -
-		    tp->rx_opt.rcv_tsecr * (LP_RESOL / HZ);
+		    tp->rx_opt.rcv_tsecr * (LP_RESOL / TCP_TS_HZ);
 		if (owd < 0)
 			owd = -owd;
 	}
@@ -264,18 +264,19 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct lp *lp = inet_csk_ca(sk);
+	u32 now = tcp_time_stamp(tp);
 	u32 delta;
 
 	if (sample->rtt_us > 0)
 		tcp_lp_rtt_sample(sk, sample->rtt_us);
 
 	/* calc inference */
-	delta = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+	delta = now - tp->rx_opt.rcv_tsecr;
 	if ((s32)delta > 0)
 		lp->inference = 3 * delta;
 
 	/* test if within inference */
-	if (lp->last_drop && (tcp_time_stamp - lp->last_drop < lp->inference))
+	if (lp->last_drop && (now - lp->last_drop < lp->inference))
 		lp->flag |= LP_WITHIN_INF;
 	else
 		lp->flag &= ~LP_WITHIN_INF;
@@ -312,7 +313,7 @@ static void tcp_lp_pkts_acked(struct sock *sk, const struct ack_sample *sample)
 		tp->snd_cwnd = max(tp->snd_cwnd >> 1U, 1U);
 
 	/* record this drop time */
-	lp->last_drop = tcp_time_stamp;
+	lp->last_drop = now;
 }
 
 static struct tcp_congestion_ops tcp_lp __read_mostly = {

net/ipv4/tcp_metrics.c

@@ -524,7 +524,7 @@ void tcp_init_metrics(struct sock *sk)
 		tp->snd_cwnd = 1;
 	else
 		tp->snd_cwnd = tcp_init_cwnd(tp, dst);
-	tp->snd_cwnd_stamp = tcp_time_stamp;
+	tp->snd_cwnd_stamp = tcp_jiffies32;
 }
 
 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst)

net/ipv4/tcp_minisocks.c

@@ -445,9 +445,9 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 
 		newtp->srtt_us = 0;
 		newtp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
-		minmax_reset(&newtp->rtt_min, tcp_time_stamp, ~0U);
+		minmax_reset(&newtp->rtt_min, tcp_jiffies32, ~0U);
 		newicsk->icsk_rto = TCP_TIMEOUT_INIT;
-		newicsk->icsk_ack.lrcvtime = tcp_time_stamp;
+		newicsk->icsk_ack.lrcvtime = tcp_jiffies32;
 
 		newtp->packets_out = 0;
 		newtp->retrans_out = 0;
@@ -455,7 +455,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 		newtp->fackets_out = 0;
 		newtp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 		newtp->tlp_high_seq = 0;
-		newtp->lsndtime = treq->snt_synack.stamp_jiffies;
+		newtp->lsndtime = tcp_jiffies32;
 		newsk->sk_txhash = treq->txhash;
 		newtp->last_oow_ack_time = 0;
 		newtp->total_retrans = req->num_retrans;
@@ -526,7 +526,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 		newtp->fastopen_req = NULL;
 		newtp->fastopen_rsk = NULL;
 		newtp->syn_data_acked = 0;
-		newtp->rack.mstamp.v64 = 0;
+		newtp->rack.mstamp = 0;
 		newtp->rack.advanced = 0;
 
 		__TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);

net/ipv4/tcp_output.c

@@ -151,7 +151,7 @@ void tcp_cwnd_restart(struct sock *sk, s32 delta)
 	while ((delta -= inet_csk(sk)->icsk_rto) > 0 && cwnd > restart_cwnd)
 		cwnd >>= 1;
 	tp->snd_cwnd = max(cwnd, restart_cwnd);
-	tp->snd_cwnd_stamp = tcp_time_stamp;
+	tp->snd_cwnd_stamp = tcp_jiffies32;
 	tp->snd_cwnd_used = 0;
 }
 
@@ -160,7 +160,7 @@ static void tcp_event_data_sent(struct tcp_sock *tp,
 				struct sock *sk)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
-	const u32 now = tcp_time_stamp;
+	const u32 now = tcp_jiffies32;
 
 	if (tcp_packets_in_flight(tp) == 0)
 		tcp_ca_event(sk, CA_EVENT_TX_START);
@@ -997,8 +997,8 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	BUG_ON(!skb || !tcp_skb_pcount(skb));
 	tp = tcp_sk(sk);
 
+	skb->skb_mstamp = tp->tcp_mstamp;
 	if (clone_it) {
-		skb_mstamp_get(&skb->skb_mstamp);
 		TCP_SKB_CB(skb)->tx.in_flight = TCP_SKB_CB(skb)->end_seq
 			- tp->snd_una;
 		tcp_rate_skb_sent(sk, skb);
@@ -1475,7 +1475,7 @@ void tcp_mtup_init(struct sock *sk)
 	icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, net->ipv4.sysctl_tcp_base_mss);
 	icsk->icsk_mtup.probe_size = 0;
 	if (icsk->icsk_mtup.enabled)
-		icsk->icsk_mtup.probe_timestamp = tcp_time_stamp;
+		icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
 }
 EXPORT_SYMBOL(tcp_mtup_init);
 
@@ -1576,7 +1576,7 @@ static void tcp_cwnd_application_limited(struct sock *sk)
 		}
 		tp->snd_cwnd_used = 0;
 	}
-	tp->snd_cwnd_stamp = tcp_time_stamp;
+	tp->snd_cwnd_stamp = tcp_jiffies32;
 }
 
 static void tcp_cwnd_validate(struct sock *sk, bool is_cwnd_limited)
@@ -1597,14 +1597,14 @@ static void tcp_cwnd_validate(struct sock *sk, bool is_cwnd_limited)
 	if (tcp_is_cwnd_limited(sk)) {
 		/* Network is feed fully. */
 		tp->snd_cwnd_used = 0;
-		tp->snd_cwnd_stamp = tcp_time_stamp;
+		tp->snd_cwnd_stamp = tcp_jiffies32;
 	} else {
 		/* Network starves. */
 		if (tp->packets_out > tp->snd_cwnd_used)
 			tp->snd_cwnd_used = tp->packets_out;
 
 		if (sysctl_tcp_slow_start_after_idle &&
-		    (s32)(tcp_time_stamp - tp->snd_cwnd_stamp) >= inet_csk(sk)->icsk_rto &&
+		    (s32)(tcp_jiffies32 - tp->snd_cwnd_stamp) >= inet_csk(sk)->icsk_rto &&
 		    !ca_ops->cong_control)
 			tcp_cwnd_application_limited(sk);
 
@@ -1906,7 +1906,6 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	u32 age, send_win, cong_win, limit, in_flight;
 	struct tcp_sock *tp = tcp_sk(sk);
-	struct skb_mstamp now;
 	struct sk_buff *head;
 	int win_divisor;
 
@@ -1919,7 +1918,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 	/* Avoid bursty behavior by allowing defer
 	 * only if the last write was recent.
 	 */
-	if ((s32)(tcp_time_stamp - tp->lsndtime) > 0)
+	if ((s32)(tcp_jiffies32 - tp->lsndtime) > 0)
 		goto send_now;
 
 	in_flight = tcp_packets_in_flight(tp);
@@ -1962,8 +1961,8 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb,
 	}
 
 	head = tcp_write_queue_head(sk);
-	skb_mstamp_get(&now);
-	age = skb_mstamp_us_delta(&now, &head->skb_mstamp);
+
+	age = tcp_stamp_us_delta(tp->tcp_mstamp, head->skb_mstamp);
 	/* If next ACK is likely to come too late (half srtt), do not defer */
 	if (age < (tp->srtt_us >> 4))
 		goto send_now;
@@ -1988,7 +1987,7 @@ static inline void tcp_mtu_check_reprobe(struct sock *sk)
 	s32 delta;
 
 	interval = net->ipv4.sysctl_tcp_probe_interval;
-	delta = tcp_time_stamp - icsk->icsk_mtup.probe_timestamp;
+	delta = tcp_jiffies32 - icsk->icsk_mtup.probe_timestamp;
 	if (unlikely(delta >= interval * HZ)) {
 		int mss = tcp_current_mss(sk);
 
@@ -2000,7 +1999,7 @@ static inline void tcp_mtu_check_reprobe(struct sock *sk)
 		icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
 
 		/* Update probe time stamp */
-		icsk->icsk_mtup.probe_timestamp = tcp_time_stamp;
+		icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
 	}
 }
 
@@ -2203,7 +2202,7 @@ static bool tcp_small_queue_check(struct sock *sk, const struct sk_buff *skb,
 
 static void tcp_chrono_set(struct tcp_sock *tp, const enum tcp_chrono new)
 {
-	const u32 now = tcp_time_stamp;
+	const u32 now = tcp_jiffies32;
 
 	if (tp->chrono_type > TCP_CHRONO_UNSPEC)
 		tp->chrono_stat[tp->chrono_type - 1] += now - tp->chrono_start;
@@ -2280,6 +2279,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 	}
 
 	max_segs = tcp_tso_segs(sk, mss_now);
+	tcp_mstamp_refresh(tp);
 	while ((skb = tcp_send_head(sk))) {
 		unsigned int limit;
 
@@ -2291,7 +2291,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 
 		if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE) {
 			/* "skb_mstamp" is used as a start point for the retransmit timer */
-			skb_mstamp_get(&skb->skb_mstamp);
+			skb->skb_mstamp = tp->tcp_mstamp;
 			goto repair; /* Skip network transmission */
 		}
 
@@ -2418,10 +2418,10 @@ bool tcp_schedule_loss_probe(struct sock *sk)
 	timeout = max_t(u32, timeout, msecs_to_jiffies(10));
 
 	/* If RTO is shorter, just schedule TLP in its place. */
-	tlp_time_stamp = tcp_time_stamp + timeout;
+	tlp_time_stamp = tcp_jiffies32 + timeout;
 	rto_time_stamp = (u32)inet_csk(sk)->icsk_timeout;
 	if ((s32)(tlp_time_stamp - rto_time_stamp) > 0) {
-		s32 delta = rto_time_stamp - tcp_time_stamp;
+		s32 delta = rto_time_stamp - tcp_jiffies32;
 		if (delta > 0)
 			timeout = delta;
 	}
@@ -2879,7 +2879,7 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs)
 		     skb_headroom(skb) >= 0xFFFF)) {
 		struct sk_buff *nskb;
 
-		skb_mstamp_get(&skb->skb_mstamp);
+		skb->skb_mstamp = tp->tcp_mstamp;
 		nskb = __pskb_copy(skb, MAX_TCP_HEADER, GFP_ATOMIC);
 		err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
 			     -ENOBUFS;
@@ -3095,7 +3095,7 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 	skb_reserve(skb, MAX_TCP_HEADER);
 	tcp_init_nondata_skb(skb, tcp_acceptable_seq(sk),
 			     TCPHDR_ACK | TCPHDR_RST);
-	skb_mstamp_get(&skb->skb_mstamp);
+	tcp_mstamp_refresh(tcp_sk(sk));
 	/* Send it off. */
 	if (tcp_transmit_skb(sk, skb, 0, priority))
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTFAILED);
@@ -3191,10 +3191,10 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
 	memset(&opts, 0, sizeof(opts));
 #ifdef CONFIG_SYN_COOKIES
 	if (unlikely(req->cookie_ts))
-		skb->skb_mstamp.stamp_jiffies = cookie_init_timestamp(req);
+		skb->skb_mstamp = cookie_init_timestamp(req);
 	else
 #endif
-	skb_mstamp_get(&skb->skb_mstamp);
+		skb->skb_mstamp = tcp_clock_us();
 
 #ifdef CONFIG_TCP_MD5SIG
 	rcu_read_lock();
@@ -3324,7 +3324,7 @@ static void tcp_connect_init(struct sock *sk)
 	if (likely(!tp->repair))
 		tp->rcv_nxt = 0;
 	else
-		tp->rcv_tstamp = tcp_time_stamp;
+		tp->rcv_tstamp = tcp_jiffies32;
 	tp->rcv_wup = tp->rcv_nxt;
 	tp->copied_seq = tp->rcv_nxt;
 
@@ -3453,7 +3453,8 @@ int tcp_connect(struct sock *sk)
 		return -ENOBUFS;
 
 	tcp_init_nondata_skb(buff, tp->write_seq++, TCPHDR_SYN);
-	tp->retrans_stamp = tcp_time_stamp;
+	tcp_mstamp_refresh(tp);
+	tp->retrans_stamp = tcp_time_stamp(tp);
 	tcp_connect_queue_skb(sk, buff);
 	tcp_ecn_send_syn(sk, buff);
 
@@ -3572,7 +3573,6 @@ void tcp_send_ack(struct sock *sk)
 	skb_set_tcp_pure_ack(buff);
 
 	/* Send it off, this clears delayed acks for us. */
-	skb_mstamp_get(&buff->skb_mstamp);
 	tcp_transmit_skb(sk, buff, 0, (__force gfp_t)0);
 }
 EXPORT_SYMBOL_GPL(tcp_send_ack);
@@ -3606,15 +3606,16 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent, int mib)
 	 * send it.
 	 */
 	tcp_init_nondata_skb(skb, tp->snd_una - !urgent, TCPHDR_ACK);
-	skb_mstamp_get(&skb->skb_mstamp);
 	NET_INC_STATS(sock_net(sk), mib);
 	return tcp_transmit_skb(sk, skb, 0, (__force gfp_t)0);
 }
 
+/* Called from setsockopt( ... TCP_REPAIR ) */
 void tcp_send_window_probe(struct sock *sk)
 {
 	if (sk->sk_state == TCP_ESTABLISHED) {
 		tcp_sk(sk)->snd_wl1 = tcp_sk(sk)->rcv_nxt - 1;
+		tcp_mstamp_refresh(tcp_sk(sk));
 		tcp_xmit_probe_skb(sk, 0, LINUX_MIB_TCPWINPROBE);
 	}
 }

net/ipv4/tcp_rate.c

@@ -78,7 +78,7 @@ void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
 
-	if (!scb->tx.delivered_mstamp.v64)
+	if (!scb->tx.delivered_mstamp)
 		return;
 
 	if (!rs->prior_delivered ||
@@ -89,9 +89,9 @@ void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
 		rs->is_retrans	     = scb->sacked & TCPCB_RETRANS;
 
 		/* Find the duration of the "send phase" of this window: */
-		rs->interval_us      = skb_mstamp_us_delta(
-						&skb->skb_mstamp,
-						&scb->tx.first_tx_mstamp);
+		rs->interval_us      = tcp_stamp_us_delta(
+						skb->skb_mstamp,
+						scb->tx.first_tx_mstamp);
 
 		/* Record send time of most recently ACKed packet: */
 		tp->first_tx_mstamp  = skb->skb_mstamp;
@@ -101,7 +101,7 @@ void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
 	 * we don't need to reset since it'll be freed soon.
 	 */
 	if (scb->sacked & TCPCB_SACKED_ACKED)
-		scb->tx.delivered_mstamp.v64 = 0;
+		scb->tx.delivered_mstamp = 0;
 }
 
 /* Update the connection delivery information and generate a rate sample. */
@@ -125,7 +125,7 @@ void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
 	rs->acked_sacked = delivered;	/* freshly ACKed or SACKed */
 	rs->losses = lost;		/* freshly marked lost */
 	/* Return an invalid sample if no timing information is available. */
-	if (!rs->prior_mstamp.v64) {
+	if (!rs->prior_mstamp) {
 		rs->delivered = -1;
 		rs->interval_us = -1;
 		return;
@@ -138,8 +138,8 @@ void tcp_rate_gen(struct sock *sk, u32 delivered, u32 lost,
 	 * longer phase.
 	 */
 	snd_us = rs->interval_us;				/* send phase */
-	ack_us = skb_mstamp_us_delta(&tp->tcp_mstamp,
-				     &rs->prior_mstamp); /* ack phase */
+	ack_us = tcp_stamp_us_delta(tp->tcp_mstamp,
+				    rs->prior_mstamp); /* ack phase */
 	rs->interval_us = max(snd_us, ack_us);
 
 	/* Normally we expect interval_us >= min-rtt.

net/ipv4/tcp_recovery.c

@@ -17,12 +17,9 @@ static void tcp_rack_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
 	}
 }
 
-static bool tcp_rack_sent_after(const struct skb_mstamp *t1,
-				const struct skb_mstamp *t2,
-				u32 seq1, u32 seq2)
+static bool tcp_rack_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2)
 {
-	return skb_mstamp_after(t1, t2) ||
-	       (t1->v64 == t2->v64 && after(seq1, seq2));
+	return t1 > t2 || (t1 == t2 && after(seq1, seq2));
 }
 
 /* RACK loss detection (IETF draft draft-ietf-tcpm-rack-01):
@@ -72,14 +69,14 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout)
 		    scb->sacked & TCPCB_SACKED_ACKED)
 			continue;
 
-		if (tcp_rack_sent_after(&tp->rack.mstamp, &skb->skb_mstamp,
+		if (tcp_rack_sent_after(tp->rack.mstamp, skb->skb_mstamp,
 					tp->rack.end_seq, scb->end_seq)) {
 			/* Step 3 in draft-cheng-tcpm-rack-00.txt:
 			 * A packet is lost if its elapsed time is beyond
 			 * the recent RTT plus the reordering window.
 			 */
-			u32 elapsed = skb_mstamp_us_delta(&tp->tcp_mstamp,
-							  &skb->skb_mstamp);
+			u32 elapsed = tcp_stamp_us_delta(tp->tcp_mstamp,
+							 skb->skb_mstamp);
 			s32 remaining = tp->rack.rtt_us + reo_wnd - elapsed;
 
 			if (remaining < 0) {
@@ -127,16 +124,16 @@ 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)
+		      u64 xmit_time)
 {
 	u32 rtt_us;
 
-	if (tp->rack.mstamp.v64 &&
-	    !tcp_rack_sent_after(xmit_time, &tp->rack.mstamp,
+	if (tp->rack.mstamp &&
+	    !tcp_rack_sent_after(xmit_time, tp->rack.mstamp,
 				 end_seq, tp->rack.end_seq))
 		return;
 
-	rtt_us = skb_mstamp_us_delta(&tp->tcp_mstamp, xmit_time);
+	rtt_us = tcp_stamp_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
@@ -152,7 +149,7 @@ void tcp_rack_advance(struct tcp_sock *tp, u8 sacked, u32 end_seq,
 			return;
 	}
 	tp->rack.rtt_us = rtt_us;
-	tp->rack.mstamp = *xmit_time;
+	tp->rack.mstamp = xmit_time;
 	tp->rack.end_seq = end_seq;
 	tp->rack.advanced = 1;
 }
@@ -166,7 +163,6 @@ void tcp_rack_reo_timeout(struct sock *sk)
 	u32 timeout, prior_inflight;
 
 	prior_inflight = tcp_packets_in_flight(tp);
-	skb_mstamp_get(&tp->tcp_mstamp);
 	tcp_rack_detect_loss(sk, &timeout);
 	if (prior_inflight != tcp_packets_in_flight(tp)) {
 		if (inet_csk(sk)->icsk_ca_state != TCP_CA_Recovery) {

net/ipv4/tcp_timer.c

@@ -63,7 +63,7 @@ static int tcp_out_of_resources(struct sock *sk, bool do_reset)
 
 	/* If peer does not open window for long time, or did not transmit
 	 * anything for long time, penalize it. */
-	if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
+	if ((s32)(tcp_jiffies32 - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
 		shift++;
 
 	/* If some dubious ICMP arrived, penalize even more. */
@@ -73,7 +73,7 @@ static int tcp_out_of_resources(struct sock *sk, bool do_reset)
 	if (tcp_check_oom(sk, shift)) {
 		/* Catch exceptional cases, when connection requires reset.
 		 *      1. Last segment was sent recently. */
-		if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN ||
+		if ((s32)(tcp_jiffies32 - tp->lsndtime) <= TCP_TIMEWAIT_LEN ||
 		    /*  2. Window is closed. */
 		    (!tp->snd_wnd && !tp->packets_out))
 			do_reset = true;
@@ -115,7 +115,7 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
 	if (net->ipv4.sysctl_tcp_mtu_probing) {
 		if (!icsk->icsk_mtup.enabled) {
 			icsk->icsk_mtup.enabled = 1;
-			icsk->icsk_mtup.probe_timestamp = tcp_time_stamp;
+			icsk->icsk_mtup.probe_timestamp = tcp_jiffies32;
 			tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
 		} else {
 			struct net *net = sock_net(sk);
@@ -153,8 +153,8 @@ static bool retransmits_timed_out(struct sock *sk,
 				  unsigned int timeout,
 				  bool syn_set)
 {
-	unsigned int linear_backoff_thresh, start_ts;
 	unsigned int rto_base = syn_set ? TCP_TIMEOUT_INIT : TCP_RTO_MIN;
+	unsigned int linear_backoff_thresh, start_ts;
 
 	if (!inet_csk(sk)->icsk_retransmits)
 		return false;
@@ -172,7 +172,7 @@ static bool retransmits_timed_out(struct sock *sk,
 			timeout = ((2 << linear_backoff_thresh) - 1) * rto_base +
 				(boundary - linear_backoff_thresh) * TCP_RTO_MAX;
 	}
-	return (tcp_time_stamp - start_ts) >= timeout;
+	return (tcp_time_stamp(tcp_sk(sk)) - start_ts) >= jiffies_to_msecs(timeout);
 }
 
 /* A write timeout has occurred. Process the after effects. */
@@ -339,9 +339,9 @@ static void tcp_probe_timer(struct sock *sk)
 	 */
 	start_ts = tcp_skb_timestamp(tcp_send_head(sk));
 	if (!start_ts)
-		skb_mstamp_get(&tcp_send_head(sk)->skb_mstamp);
+		tcp_send_head(sk)->skb_mstamp = tp->tcp_mstamp;
 	else if (icsk->icsk_user_timeout &&
-		 (s32)(tcp_time_stamp - start_ts) > icsk->icsk_user_timeout)
+		 (s32)(tcp_time_stamp(tp) - start_ts) > icsk->icsk_user_timeout)
 		goto abort;
 
 	max_probes = sock_net(sk)->ipv4.sysctl_tcp_retries2;
@@ -451,7 +451,7 @@ void tcp_retransmit_timer(struct sock *sk)
 					    tp->snd_una, tp->snd_nxt);
 		}
 #endif
-		if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) {
+		if (tcp_jiffies32 - tp->rcv_tstamp > TCP_RTO_MAX) {
 			tcp_write_err(sk);
 			goto out;
 		}
@@ -561,6 +561,7 @@ void tcp_write_timer_handler(struct sock *sk)
 		goto out;
 	}
 
+	tcp_mstamp_refresh(tcp_sk(sk));
 	event = icsk->icsk_pending;
 
 	switch (event) {

net/ipv4/tcp_westwood.c

@@ -68,7 +68,7 @@ static void tcp_westwood_init(struct sock *sk)
 	w->cumul_ack = 0;
 	w->reset_rtt_min = 1;
 	w->rtt_min = w->rtt = TCP_WESTWOOD_INIT_RTT;
-	w->rtt_win_sx = tcp_time_stamp;
+	w->rtt_win_sx = tcp_jiffies32;
 	w->snd_una = tcp_sk(sk)->snd_una;
 	w->first_ack = 1;
 }
@@ -116,7 +116,7 @@ static void tcp_westwood_pkts_acked(struct sock *sk,
 static void westwood_update_window(struct sock *sk)
 {
 	struct westwood *w = inet_csk_ca(sk);
-	s32 delta = tcp_time_stamp - w->rtt_win_sx;
+	s32 delta = tcp_jiffies32 - w->rtt_win_sx;
 
 	/* Initialize w->snd_una with the first acked sequence number in order
 	 * to fix mismatch between tp->snd_una and w->snd_una for the first
@@ -140,7 +140,7 @@ static void westwood_update_window(struct sock *sk)
 		westwood_filter(w, delta);
 
 		w->bk = 0;
-		w->rtt_win_sx = tcp_time_stamp;
+		w->rtt_win_sx = tcp_jiffies32;
 	}
 }
 

net/ipv6/syncookies.c

@@ -211,7 +211,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 	ireq->wscale_ok		= tcp_opt.wscale_ok;
 	ireq->tstamp_ok		= tcp_opt.saw_tstamp;
 	req->ts_recent		= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
-	treq->snt_synack.v64	= 0;
+	treq->snt_synack	= 0;
 	treq->rcv_isn = ntohl(th->seq) - 1;
 	treq->snt_isn = cookie;
 	treq->ts_off = 0;

net/ipv6/tcp_ipv6.c

@@ -949,7 +949,7 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 
 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
-			tcp_time_stamp + tcptw->tw_ts_offset,
+			tcp_time_stamp_raw() + tcptw->tw_ts_offset,
 			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel));
 
@@ -971,7 +971,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
 			tcp_rsk(req)->rcv_nxt,
 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
-			tcp_time_stamp + tcp_rsk(req)->ts_off,
+			tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
 			req->ts_recent, sk->sk_bound_dev_if,
 			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr),
 			0, 0);

net/netfilter/nf_synproxy_core.c

@@ -152,7 +152,7 @@ void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info,
 				    struct synproxy_options *opts)
 {
 	opts->tsecr = opts->tsval;
-	opts->tsval = tcp_time_stamp & ~0x3f;
+	opts->tsval = tcp_time_stamp_raw() & ~0x3f;
 
 	if (opts->options & XT_SYNPROXY_OPT_WSCALE) {
 		opts->tsval |= opts->wscale;