From: Gang Yan Add __mptcp_subflow_set_rcvbuf() helper that calls the tcp_set_rcvbuf to update window_clamp, in addition to writing sk_rcvbuf. Use it in both mptcp_sol_socket_sync_intval() (setsockopt path) and sync_socket_options() (new subflow creation path). Fixes: a2cbb1603943 ("tcp: Update window clamping condition") Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/619 Signed-off-by: Gang Yan --- Notes: Hi Matt: Note that I do not implement set_rcvbuf in mptcp_stream_ops for the following reasons: - The callback receives the MPTCP meta socket as 'sk', but tcp_set_rcvbuf() must be called on each TCP subflow to update window_clamp. A callback implementation would need to iterate all subflows, duplicating the work already done by mptcp_sol_socket_sync_intval(). - Subflows are grafted to the MPTCP socket via mptcp_sock_graft(), so ssk->sk_socket->ops points to mptcp_stream_ops, not inet_stream_ops. This means the TCP set_rcvbuf callback is not reachable through the subflow's ops either. - The existing subflow sync functions cover both the setsockopt path (mptcp_sol_socket_sync_intval) and new subflow creation path (sync_socket_options), making the proto_ops callback unnecessary. WDYT？ The packetdrill tests is also implemented: -Link: https://github.com/multipath-tcp/packetdrill/pull/194 Thanks Gang --- net/mptcp/sockopt.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index de90a2897d2d..abe63392826b 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -67,6 +67,12 @@ static int mptcp_get_int_option(struct mptcp_sock *msk, sockptr_t optval, return 0; } +static inline void __mptcp_subflow_set_rcvbuf(struct sock *ssk, int val) +{ + WRITE_ONCE(ssk->sk_rcvbuf, val); + tcp_set_rcvbuf(ssk, val); +} + static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, int val) { struct mptcp_subflow_context *subflow; @@ -100,7 +106,7 @@ static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, in case SO_RCVBUF: case SO_RCVBUFFORCE: ssk->sk_userlocks |= SOCK_RCVBUF_LOCK; - WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf); + __mptcp_subflow_set_rcvbuf(ssk, sk->sk_rcvbuf); break; case SO_MARK: if (READ_ONCE(ssk->sk_mark) != sk->sk_mark) { @@ -1556,7 +1562,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk) mptcp_subflow_ctx(ssk)->cached_sndbuf = sk->sk_sndbuf; } if (sk->sk_userlocks & SOCK_RCVBUF_LOCK) - WRITE_ONCE(ssk->sk_rcvbuf, sk->sk_rcvbuf); + __mptcp_subflow_set_rcvbuf(ssk, sk->sk_rcvbuf); } if (sock_flag(sk, SOCK_LINGER)) { -- 2.43.0