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>
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 67a61ac..d87cc04 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -387,6 +387,7 @@ struct mptcp_delegated_action {
DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
#define MPTCP_DELEGATE_SEND 0
+#define MPTCP_DELEGATE_ACK 1
/* MPTCP subflow context */
struct mptcp_subflow_context {
@@ -492,23 +493,23 @@ static inline void mptcp_add_pending_subflow(struct mptcp_sock *msk,
void mptcp_subflow_process_delegated(struct sock *ssk);
-static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow)
+static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow, int action)
{
struct mptcp_delegated_action *delegated;
bool schedule;
+ /* the caller held the subflow bh socket lock */
+ lockdep_assert_in_softirq();
+
/* The implied barrier pairs with mptcp_subflow_delegated_done(), and
* ensures the below list check sees list updates done prior to status
* bit changes
*/
- if (!test_and_set_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) {
+ if (!test_and_set_bit(action, &subflow->delegated_status)) {
/* still on delegated list from previous scheduling */
if (!list_empty(&subflow->delegated_node))
return;
- /* the caller held the subflow bh socket lock */
- lockdep_assert_in_softirq();
-
delegated = this_cpu_ptr(&mptcp_delegated_actions);
schedule = list_empty(&delegated->head);
list_add_tail(&subflow->delegated_node, &delegated->head);
@@ -533,16 +534,16 @@ mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
static inline bool mptcp_subflow_has_delegated_action(const struct mptcp_subflow_context *subflow)
{
- return test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
+ return !!READ_ONCE(subflow->delegated_status);
}
-static inline void mptcp_subflow_delegated_done(struct mptcp_subflow_context *subflow)
+static inline void mptcp_subflow_delegated_done(struct mptcp_subflow_context *subflow, int action)
{
/* pairs with mptcp_subflow_delegate, ensures delegate_node is updated before
* touching the status bit
*/
smp_wmb();
- clear_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status);
+ clear_bit(action, &subflow->delegated_status);
}
int mptcp_is_enabled(const struct net *net);