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authorPaolo Abeni <pabeni@redhat.com>2021-11-19 17:27:55 +0300
committerDavid S. Miller <davem@davemloft.net>2021-11-20 17:24:00 +0300
commitbcd97734318d1d87bb237dbc0a60c81237b0ac50 (patch)
treeca2ece9d265062219bf920c4c441f2eb7017c998 /net/mptcp/options.c
parentee50e67ba0e17b1a1a8d76691d02eadf9e0f392c (diff)
downloadlinux-bcd97734318d1d87bb237dbc0a60c81237b0ac50.tar.xz
mptcp: use delegate action to schedule 3rd ack retrans
Scheduling a delack in mptcp_established_options_mp() is not a good idea: such function is called by tcp_send_ack() and the pending delayed ack will be cleared shortly after by the tcp_event_ack_sent() call in __tcp_transmit_skb(). Instead use the mptcp delegated action infrastructure to schedule the delayed ack after the current bh processing completes. Additionally moves the schedule_3rdack_retransmission() helper into protocol.c to avoid making it visible in a different compilation unit. Fixes: ec3edaa7ca6ce02f ("mptcp: Add handling of outgoing MP_JOIN requests") Reviewed-by: Mat Martineau <mathew.j.martineau>@linux.intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mptcp/options.c')
-rw-r--r--net/mptcp/options.c33
1 files changed, 9 insertions, 24 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 2e9b73eeeeb5..fe98e4f475ba 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -422,29 +422,6 @@ bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
return false;
}
-/* MP_JOIN client subflow must wait for 4th ack before sending any data:
- * TCP can't schedule delack timer before the subflow is fully established.
- * MPTCP uses the delack timer to do 3rd ack retransmissions
- */
-static void schedule_3rdack_retransmission(struct sock *sk)
-{
- struct inet_connection_sock *icsk = inet_csk(sk);
- struct tcp_sock *tp = tcp_sk(sk);
- unsigned long timeout;
-
- /* reschedule with a timeout above RTT, as we must look only for drop */
- if (tp->srtt_us)
- timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
- else
- timeout = TCP_TIMEOUT_INIT;
- timeout += jiffies;
-
- WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
- icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
- icsk->icsk_ack.timeout = timeout;
- sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
-}
-
static void clear_3rdack_retransmission(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
@@ -527,7 +504,15 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
*size = TCPOLEN_MPTCP_MPJ_ACK;
pr_debug("subflow=%p", subflow);
- schedule_3rdack_retransmission(sk);
+ /* we can use the full delegate action helper only from BH context
+ * If we are in process context - sk is flushing the backlog at
+ * socket lock release time - just set the appropriate flag, will
+ * be handled by the release callback
+ */
+ if (sock_owned_by_user(sk))
+ set_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status);
+ else
+ mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_ACK);
return true;
}
return false;