rxrpc: Add a tracepoint to follow the life of a packet in the Tx buffer

Add a tracepoint to follow the insertion of a packet into the transmit
buffer, its transmission and its rotation out of the buffer.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index 598064d..dca8999 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -132,3 +132,12 @@
 	[rxrpc_client_to_waiting]	= "->Wait",
 	[rxrpc_client_uncount]		= "Uncoun",
 };
+
+const char rxrpc_transmit_traces[rxrpc_transmit__nr_trace][4] = {
+	[rxrpc_transmit_wait]		= "WAI",
+	[rxrpc_transmit_queue]		= "QUE",
+	[rxrpc_transmit_queue_reqack]	= "QRA",
+	[rxrpc_transmit_queue_last]	= "QLS",
+	[rxrpc_transmit_rotate]		= "ROT",
+	[rxrpc_transmit_end]		= "END",
+};