linux-kernel - [PATCH net-next 5/5] mptcp: fastclose msk when cleaning unaccepted sockets

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Date:   Fri, 14 Apr 2023 16:08:04 +0200
From:   Matthieu Baerts <matthieu.baerts@...sares.net>
To:     mptcp@...ts.linux.dev, "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     Ondrej Mosnacek <omosnace@...hat.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Matthieu Baerts <matthieu.baerts@...sares.net>
Subject: [PATCH net-next 5/5] mptcp: fastclose msk when cleaning unaccepted
 sockets

From: Paolo Abeni <pabeni@...hat.com>

When cleaning up unaccepted mptcp socket still laying inside
the listener queue at listener close time, such sockets will
go through a regular close, waiting for a timeout before
shutting down the subflows.

There is no need to keep the kernel resources in use for
such a possibly long time: short-circuit to fast-close.

Signed-off-by: Paolo Abeni <pabeni@...hat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@...sares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@...sares.net>
---
 net/mptcp/protocol.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index a676ac1bb9f1..1926b81a9538 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2953,10 +2953,13 @@ bool __mptcp_close(struct sock *sk, long timeout)
 		goto cleanup;
 	}
 
-	if (mptcp_check_readable(msk)) {
-		/* the msk has read data, do the MPTCP equivalent of TCP reset */
+	if (mptcp_check_readable(msk) || timeout < 0) {
+		/* If the msk has read data, or the caller explicitly ask it,
+		 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose
+		 */
 		inet_sk_state_store(sk, TCP_CLOSE);
 		mptcp_do_fastclose(sk);
+		timeout = 0;
 	} else if (mptcp_close_state(sk)) {
 		__mptcp_wr_shutdown(sk);
 	}

-- 
2.39.2