diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2021-07-09 17:20:51 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-07-09 18:38:53 -0700 |
| commit | ce599c516386f09ca30848a1a4eb93d3fffbe187 (patch) | |
| tree | 25e8811ed4d7a8fbfea62409158434e5e27ac77b /net/mptcp/protocol.h | |
| parent | a7da441621c7945fbfd43ed239c93b8073cda502 (diff) | |
mptcp: properly account bulk freed memory
After commit 879526030c8b ("mptcp: protect the rx path with
the msk socket spinlock") the rmem currently used by a given
msk is really sk_rmem_alloc - rmem_released.
The safety check in mptcp_data_ready() does not take the above
in due account, as a result legit incoming data is kept in
subflow receive queue with no reason, delaying or blocking
MPTCP-level ack generation.
This change addresses the issue introducing a new helper to fetch
the rmem memory and using it as needed. Additionally add a MIB
counter for the exceptional event described above - the peer is
misbehaving.
Finally, introduce the required annotation when rmem_released is
updated.
Fixes: 879526030c8b ("mptcp: protect the rx path with the msk socket spinlock")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/211
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mptcp/protocol.h')
| -rw-r--r-- | net/mptcp/protocol.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 426ed80fe72f..0f0c026c5f8b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -296,9 +296,17 @@ static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) return (struct mptcp_sock *)sk; } +/* the msk socket don't use the backlog, also account for the bulk + * free memory + */ +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_space(const struct sock *sk) { - return tcp_space(sk) + READ_ONCE(mptcp_sk(sk)->rmem_released); + return tcp_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) |