rxrpc: Reinitialise the call ACK and timer state for client reply phase

Clear the ACK reason, ACK timer and resend timer when entering the client
reply phase when the first DATA packet is received.  New ACKs will be
proposed once the data is queued.

The resend timer is no longer relevant and we need to cancel ACKs scheduled
to probe for a lost reply.
Signed-off-by: David Howells <dhowells@redhat.com>

net/rxrpc/ar-internal.h

@@ -682,6 +682,7 @@ extern const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5];
 
 enum rxrpc_timer_trace {
 	rxrpc_timer_begin,
+	rxrpc_timer_init_for_reply,
 	rxrpc_timer_expired,
 	rxrpc_timer_set_for_ack,
 	rxrpc_timer_set_for_resend,

net/rxrpc/input.c

@@ -149,6 +149,15 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call)
 {
 	rxrpc_seq_t top = READ_ONCE(call->tx_top);
 
+	if (call->ackr_reason) {
+		spin_lock_bh(&call->lock);
+		call->ackr_reason = 0;
+		call->resend_at = call->expire_at;
+		call->ack_at = call->expire_at;
+		spin_unlock_bh(&call->lock);
+		rxrpc_set_timer(call, rxrpc_timer_init_for_reply);
+	}
+
 	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags))
 		rxrpc_rotate_tx_window(call, top);
 	if (!test_bit(RXRPC_CALL_TX_LAST, &call->flags)) {

net/rxrpc/misc.c

@@ -191,6 +191,7 @@ const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5] = {
 const char rxrpc_timer_traces[rxrpc_timer__nr_trace][8] = {
 	[rxrpc_timer_begin]			= "Begin ",
 	[rxrpc_timer_expired]			= "*EXPR*",
+	[rxrpc_timer_init_for_reply]		= "IniRpl",
 	[rxrpc_timer_set_for_ack]		= "SetAck",
 	[rxrpc_timer_set_for_send]		= "SetTx ",
 	[rxrpc_timer_set_for_resend]		= "SetRTx",