Commit 785a874c authored by Matthieu Baerts (NGI0)'s avatar Matthieu Baerts (NGI0) Committed by ZhangPeng
Browse files

mptcp: sched: check both directions for backup 

stable inclusion
from stable-v6.6.45
commit add243b7f6ceab7ad8e6e4267dc63da1a208dcd9
bugzilla: https://gitee.com/openeuler/kernel/issues/IAJEIR

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=add243b7f6ceab7ad8e6e4267dc63da1a208dcd9



--------------------------------

commit b6a66e521a2032f7fcba2af5a9bcbaeaa19b7ca3 upstream.

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: f296234c ("mptcp: Add handling of incoming MP_JOIN requests")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent fa3a4566

include/trace/events/mptcp.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

net/mptcp/protocol.c

+6 −4
Original line number Diff line number Diff line
@@ -1420,13 +1420,15 @@ 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 */
@@ -1437,9 +1439,9 @@ 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);