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| author | Paolo Abeni <pabeni@redhat.com> | 2023-07-20 21:47:50 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-07-25 02:36:05 +0300 |
| commit | b8dc6d6ce93142ccd4c976003bb6c25d63aac2ce (patch) | |
| tree | 647b7513486333643f7ce38ba7b4561a9ac952ef /net/mptcp/protocol.h | |
| parent | 004a04b97bbcbb630421e44aadfe675fe6b4c460 (diff) | |
| download | linux-b8dc6d6ce93142ccd4c976003bb6c25d63aac2ce.tar.xz | |
mptcp: fix rcv buffer auto-tuning
The MPTCP code uses the assumption that the tcp_win_from_space() helper
does not use any TCP-specific field, and thus works correctly operating
on an MPTCP socket.
The commit dfa2f0483360 ("tcp: get rid of sysctl_tcp_adv_win_scale")
broke such assumption, and as a consequence most MPTCP connections stall
on zero-window event due to auto-tuning changing the rcv buffer size
quite randomly.
Address the issue syncing again the MPTCP auto-tuning code with the TCP
one. To achieve that, factor out the windows size logic in socket
independent helpers, and reuse them in mptcp_rcv_space_adjust(). The
MPTCP level scaling_ratio is selected as the minimum one from the all
the subflows, as a worst-case estimate.
Fixes: dfa2f0483360 ("tcp: get rid of sysctl_tcp_adv_win_scale")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Link: https://lore.kernel.org/r/20230720-upstream-net-next-20230720-mptcp-fix-rcv-buffer-auto-tuning-v1-1-175ef12b8380@tessares.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp/protocol.h')
| -rw-r--r-- | net/mptcp/protocol.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 37fbe22e2433..795f422e8597 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -321,6 +321,7 @@ struct mptcp_sock { u64 time; /* start time of measurement window */ u64 rtt_us; /* last maximum rtt of subflows */ } rcvq_space; + u8 scaling_ratio; u32 subflow_id; u32 setsockopt_seq; @@ -351,9 +352,14 @@ static inline int __mptcp_rmem(const struct sock *sk) return atomic_read(&sk->sk_rmem_alloc) - READ_ONCE(mptcp_sk(sk)->rmem_released); } +static inline int mptcp_win_from_space(const struct sock *sk, int space) +{ + return __tcp_win_from_space(mptcp_sk(sk)->scaling_ratio, space); +} + static inline int __mptcp_space(const struct sock *sk) { - return tcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk)); + return mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf) - __mptcp_rmem(sk)); } static inline struct mptcp_data_frag *mptcp_send_head(const struct sock *sk) |