When working on a fix modifying mptcp_check_data_fin(), I noticed the
returned value was no longer used.

It looks like it was used for 3 days, between commit 7ed90803a213
("mptcp: send explicit ack on delayed ack_seq incr") and commit
ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling").

This returned value can be safely removed.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/protocol.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1c26acf6c4145896ecbb5c7f7004121c66a20649..f3dda47ad1d70b5c6a326c17dbe6d244c5638ca2 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -530,11 +530,10 @@ static void mptcp_cleanup_rbuf(struct mptcp_sock *msk, int copied)
 	}
 }
 
-static bool mptcp_check_data_fin(struct sock *sk)
+static void mptcp_check_data_fin(struct sock *sk)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	u64 rcv_data_fin_seq;
-	bool ret = false;
 
 	/* Need to ack a DATA_FIN received from a peer while this side
 	 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2.
@@ -572,12 +571,10 @@ static bool mptcp_check_data_fin(struct sock *sk)
 			break;
 		}
 
-		ret = true;
 		if (!__mptcp_check_fallback(msk))
 			mptcp_send_ack(msk);
 		mptcp_close_wake_up(sk);
 	}
-	return ret;
 }
 
 static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk)

---
base-commit: e9091ee333eb716a0933dcb08617228dcd3d3623
change-id: 20250906-check_data_fin_ret-6d284170880a

Best regards,
-- 
Matthieu Baerts (NGI0) <matttbe@kernel.org>

Hi Matthieu,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal: Success! ✅
- KVM Validation: debug: Unstable: 1 failed test(s): selftest_mptcp_connect_checksum 🔴
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/17515731496

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/ffb29b394e92
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=999625


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)