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| author | Paolo Abeni <pabeni@redhat.com> | 2025-12-05 19:55:16 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-12-08 23:54:03 -0800 |
| commit | 2ea6190f42d0416a4310e60a7fcb0b49fcbbd4fb (patch) | |
| tree | 78b39b0043b2dc05b7db9d20951024e207feae50 | |
| parent | 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 (diff) | |
| download | net-2ea6190f42d0416a4310e60a7fcb0b49fcbbd4fb.tar.gz | |
mptcp: schedule rtx timer only after pushing data
The MPTCP protocol usually schedule the retransmission timer only
when there is some chances for such retransmissions to happen.
With a notable exception: __mptcp_push_pending() currently schedule
such timer unconditionally, potentially leading to unnecessary rtx
timer expiration.
The issue is present since the blamed commit below but become easily
reproducible after commit 27b0e701d387 ("mptcp: drop bogus optimization
in __mptcp_check_push()")
Fixes: 33d41c9cd74c ("mptcp: more accurate timeout")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-3-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/mptcp/protocol.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index e212c1374bd043..d8a7f702916455 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1623,7 +1623,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags) struct mptcp_sendmsg_info info = { .flags = flags, }; - bool do_check_data_fin = false; + bool copied = false; int push_count = 1; while (mptcp_send_head(sk) && (push_count > 0)) { @@ -1665,7 +1665,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags) push_count--; continue; } - do_check_data_fin = true; + copied = true; } } } @@ -1674,11 +1674,14 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags) if (ssk) mptcp_push_release(ssk, &info); - /* ensure the rtx timer is running */ - if (!mptcp_rtx_timer_pending(sk)) - mptcp_reset_rtx_timer(sk); - if (do_check_data_fin) + /* Avoid scheduling the rtx timer if no data has been pushed; the timer + * will be updated on positive acks by __mptcp_cleanup_una(). + */ + if (copied) { + if (!mptcp_rtx_timer_pending(sk)) + mptcp_reset_rtx_timer(sk); mptcp_check_send_data_fin(sk); + } } static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first) |