rxrpc: Trace ack.rwind

Log ack.rwind in the rxrpc_tx_ack tracepoint.  This value is useful to see
as it represents flow-control information to the peer.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

include/trace/events/rxrpc.h

@@ -1118,9 +1118,9 @@ TRACE_EVENT(rxrpc_tx_data,
 TRACE_EVENT(rxrpc_tx_ack,
 	    TP_PROTO(unsigned int call, rxrpc_serial_t serial,
 		     rxrpc_seq_t ack_first, rxrpc_serial_t ack_serial,
-		     u8 reason, u8 n_acks),
+		     u8 reason, u8 n_acks, u16 rwind),
 
-	    TP_ARGS(call, serial, ack_first, ack_serial, reason, n_acks),
+	    TP_ARGS(call, serial, ack_first, ack_serial, reason, n_acks, rwind),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,	call)
@@ -1129,6 +1129,7 @@ TRACE_EVENT(rxrpc_tx_ack,
 		    __field(rxrpc_serial_t,	ack_serial)
 		    __field(u8,			reason)
 		    __field(u8,			n_acks)
+		    __field(u16,		rwind)
 			     ),
 
 	    TP_fast_assign(
@@ -1138,15 +1139,17 @@ TRACE_EVENT(rxrpc_tx_ack,
 		    __entry->ack_serial = ack_serial;
 		    __entry->reason = reason;
 		    __entry->n_acks = n_acks;
+		    __entry->rwind = rwind;
 			   ),
 
-	    TP_printk(" c=%08x ACK  %08x %s f=%08x r=%08x n=%u",
+	    TP_printk(" c=%08x ACK  %08x %s f=%08x r=%08x n=%u rw=%u",
 		      __entry->call,
 		      __entry->serial,
 		      __print_symbolic(__entry->reason, rxrpc_ack_names),
 		      __entry->ack_first,
 		      __entry->ack_serial,
-		      __entry->n_acks)
+		      __entry->n_acks,
+		      __entry->rwind)
 	    );
 
 TRACE_EVENT(rxrpc_receive,

net/rxrpc/conn_event.c

@@ -163,7 +163,7 @@ void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
 		trace_rxrpc_tx_ack(chan->call_debug_id, serial,
 				   ntohl(pkt.ack.firstPacket),
 				   ntohl(pkt.ack.serial),
-				   pkt.ack.reason, 0);
+				   pkt.ack.reason, 0, rxrpc_rx_window_size);
 		break;
 
 	default:

net/rxrpc/output.c

@@ -80,7 +80,8 @@ static void rxrpc_set_keepalive(struct rxrpc_call *call)
  */
 static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
 				 struct rxrpc_call *call,
-				 struct rxrpc_txbuf *txb)
+				 struct rxrpc_txbuf *txb,
+				 u16 *_rwind)
 {
 	struct rxrpc_ackinfo ackinfo;
 	unsigned int qsize, sack, wrap, to;
@@ -124,6 +125,7 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
 	jmax = rxrpc_rx_jumbo_max;
 	qsize = (window - 1) - call->rx_consumed;
 	rsize = max_t(int, call->rx_winsize - qsize, 0);
+	*_rwind = rsize;
 	ackinfo.rxMTU		= htonl(rxrpc_rx_mtu);
 	ackinfo.maxMTU		= htonl(mtu);
 	ackinfo.rwind		= htonl(rsize);
@@ -190,6 +192,7 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
 	rxrpc_serial_t serial;
 	size_t len, n;
 	int ret, rtt_slot = -1;
+	u16 rwind;
 
 	if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 		return -ECONNRESET;
@@ -205,7 +208,7 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
 	if (txb->ack.reason == RXRPC_ACK_PING)
 		txb->wire.flags |= RXRPC_REQUEST_ACK;
 
-	n = rxrpc_fill_out_ack(conn, call, txb);
+	n = rxrpc_fill_out_ack(conn, call, txb, &rwind);
 	if (n == 0)
 		return 0;
 
@@ -217,7 +220,8 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
 	txb->wire.serial = htonl(serial);
 	trace_rxrpc_tx_ack(call->debug_id, serial,
 			   ntohl(txb->ack.firstPacket),
-			   ntohl(txb->ack.serial), txb->ack.reason, txb->ack.nAcks);
+			   ntohl(txb->ack.serial), txb->ack.reason, txb->ack.nAcks,
+			   rwind);
 
 	if (txb->ack.reason == RXRPC_ACK_PING)
 		rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping);