netdev - [PATCH net-next 5/6] tcp: remove READ_ONCE(req->ts

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Message-ID: <20250228132248.25899-6-edumazet@google.com>
Date: Fri, 28 Feb 2025 13:22:47 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, Neal Cardwell <ncardwell@...gle.com>
Cc: Kuniyuki Iwashima <kuniyu@...zon.com>, Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, 
	eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>, 
	Wang Hai <wanghai38@...wei.com>
Subject: [PATCH net-next 5/6] tcp: remove READ_ONCE(req->ts_recent)

After commit 8d52da23b6c6 ("tcp: Defer ts_recent changes
until req is owned"), req->ts_recent is not changed anymore.

It is set once in tcp_openreq_init(), bpf_sk_assign_tcp_reqsk()
or cookie_tcp_reqsk_alloc() before the req can be seen by other
cpus/threads.

This completes the revert of eba20811f326 ("tcp: annotate
data-races around tcp_rsk(req)->ts_recent").

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Wang Hai <wanghai38@...wei.com>
---
 net/ipv4/tcp_ipv4.c      | 2 +-
 net/ipv4/tcp_minisocks.c | 4 ++--
 net/ipv4/tcp_output.c    | 2 +-
 net/ipv6/tcp_ipv6.c      | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ae07613e4f335063723f49d7fd70a240412922ef..d9405b012dff079f7cafd9d422ff4445a27eb064 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1155,7 +1155,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 			tcp_rsk(req)->rcv_nxt,
 			tcp_synack_window(req) >> inet_rsk(req)->rcv_wscale,
 			tcp_rsk_tsval(tcp_rsk(req)),
-			READ_ONCE(req->ts_recent),
+			req->ts_recent,
 			0, &key,
 			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
 			ip_hdr(skb)->tos,
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index ba4a5d7f251d8ed093b38155d9b1a9f50bfcfe32..3cb8f281186b205e2b03d1b78e1750a024b94f6a 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -585,7 +585,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 
 	if (newtp->rx_opt.tstamp_ok) {
 		newtp->tcp_usec_ts = treq->req_usec_ts;
-		newtp->rx_opt.ts_recent = READ_ONCE(req->ts_recent);
+		newtp->rx_opt.ts_recent = req->ts_recent;
 		newtp->rx_opt.ts_recent_stamp = ktime_get_seconds();
 		newtp->tcp_header_len = sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED;
 	} else {
@@ -673,7 +673,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
 		tcp_parse_options(sock_net(sk), skb, &tmp_opt, 0, NULL);
 
 		if (tmp_opt.saw_tstamp) {
-			tmp_opt.ts_recent = READ_ONCE(req->ts_recent);
+			tmp_opt.ts_recent = req->ts_recent;
 			if (tmp_opt.rcv_tsecr) {
 				if (inet_rsk(req)->tstamp_ok && !fastopen)
 					tsecr_reject = !between(tmp_opt.rcv_tsecr,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 0a660075add5bea05a61b4fe2d9d334a89d956a7..24e56bf96747253c1a508ddfe27ebd38da7c219e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -949,7 +949,7 @@ static unsigned int tcp_synack_options(const struct sock *sk,
 			tcp_rsk(req)->snt_tsval_first = opts->tsval;
 		}
 		WRITE_ONCE(tcp_rsk(req)->snt_tsval_last, opts->tsval);
-		opts->tsecr = READ_ONCE(req->ts_recent);
+		opts->tsecr = req->ts_recent;
 		remaining -= TCPOLEN_TSTAMP_ALIGNED;
 	}
 	if (likely(ireq->sack_ok)) {
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index fe75ad8e606cbca77d69326dc00273e7b214edee..85c4820bfe1588e4553784129d13408dea70763a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1279,7 +1279,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 			tcp_rsk(req)->rcv_nxt,
 			tcp_synack_window(req) >> inet_rsk(req)->rcv_wscale,
 			tcp_rsk_tsval(tcp_rsk(req)),
-			READ_ONCE(req->ts_recent), sk->sk_bound_dev_if,
+			req->ts_recent, sk->sk_bound_dev_if,
 			&key, ipv6_get_dsfield(ipv6_hdr(skb)), 0,
 			READ_ONCE(sk->sk_priority),
 			READ_ONCE(tcp_rsk(req)->txhash));
-- 
2.48.1.711.g2feabab25a-goog