From: Eric Dumazet <edumazet@google.com>
Date: Thu, 21 Aug 2025 14:19:01 +0000 (+0000)
Subject: tcp: lockless TCP_MAXSEG option
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=9217146fee49575dfe4ac9416587392fc31171f1;p=users%2Fwilly%2Fxarray.git

tcp: lockless TCP_MAXSEG option

setsockopt(TCP_MAXSEG) writes over a field that does not need
socket lock protection anymore.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20250821141901.18839-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a12d81e01b3f..99232903b03c 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3890,15 +3890,13 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
 		WRITE_ONCE(inet_csk(sk)->icsk_delack_max, delack_max);
 		return 0;
 	}
+	case TCP_MAXSEG:
+		return tcp_sock_set_maxseg(sk, val);
 	}
 
 	sockopt_lock_sock(sk);
 
 	switch (optname) {
-	case TCP_MAXSEG:
-		err = tcp_sock_set_maxseg(sk, val);
-		break;
-
 	case TCP_NODELAY:
 		__tcp_sock_set_nodelay(sk, val);
 		break;