The 'mptcp_subflow_context' structure has two items related to the backup flags:
- 'backup': the subflow has been marked as backup by the other peer
- 'request_bkup': the backup flag has been set by the host
Before this patch, the scheduler was only looking at the 'backup' flag. That can make sense in some cases, but it looks like that's not what we wanted for the general use, because either the path-manager was setting both of them when sending an MP_PRIO, or the receiver was duplicating the 'backup' flag in the subflow request.
Note that the use of these two flags in the path-manager are going to be fixed in the next commits, but this change here is needed not to modify the behaviour.
Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- To: Steven Rostedt rostedt@goodmis.org To: Masami Hiramatsu mhiramat@kernel.org To: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: linux-trace-kernel@vger.kernel.org --- include/trace/events/mptcp.h | 2 +- net/mptcp/protocol.c | 10 ++++++---- 2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/mptcp.h b/include/trace/events/mptcp.h index 09e72215b9f9..085b749cdd97 100644 --- a/include/trace/events/mptcp.h +++ b/include/trace/events/mptcp.h @@ -34,7 +34,7 @@ TRACE_EVENT(mptcp_subflow_get_send, struct sock *ssk;
__entry->active = mptcp_subflow_active(subflow); - __entry->backup = subflow->backup; + __entry->backup = subflow->backup || subflow->request_bkup;
if (subflow->tcp_sock && sk_fullsock(subflow->tcp_sock)) __entry->free = sk_stream_memory_free(subflow->tcp_sock); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index a26c2c840fd9..a2fc54ed68c0 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1422,13 +1422,15 @@ struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) }
mptcp_for_each_subflow(msk, subflow) { + bool backup = subflow->backup || subflow->request_bkup; + trace_mptcp_subflow_get_send(subflow); ssk = mptcp_subflow_tcp_sock(subflow); if (!mptcp_subflow_active(subflow)) continue;
tout = max(tout, mptcp_timeout_from_subflow(subflow)); - nr_active += !subflow->backup; + nr_active += !backup; pace = subflow->avg_pacing_rate; if (unlikely(!pace)) { /* init pacing rate from socket */ @@ -1439,9 +1441,9 @@ struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) }
linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); - if (linger_time < send_info[subflow->backup].linger_time) { - send_info[subflow->backup].ssk = ssk; - send_info[subflow->backup].linger_time = linger_time; + if (linger_time < send_info[backup].linger_time) { + send_info[backup].ssk = ssk; + send_info[backup].linger_time = linger_time; } } __mptcp_set_timeout(sk, tout);