rxrpc: Trace resend

Add a tracepoint to trace packet resend events and to dump the Tx
annotation buffer for added illumination.

Signed-off-by: David Howells <dhowells@rdhat.com>

include/trace/events/rxrpc.h

@@ -420,6 +420,7 @@ rxrpc_rtt_rx_traces;
 rxrpc_timer_traces;
 rxrpc_propose_ack_traces;
 rxrpc_propose_ack_outcomes;
+rxrpc_congest_modes;
 rxrpc_congest_changes;
 
 /*
@@ -1229,6 +1230,29 @@ TRACE_EVENT(rxrpc_connect_call,
 		      __entry->call_id)
 	    );
 
+TRACE_EVENT(rxrpc_resend,
+	    TP_PROTO(struct rxrpc_call *call, int ix),
+
+	    TP_ARGS(call, ix),
+
+	    TP_STRUCT__entry(
+		    __field(struct rxrpc_call *,	call		)
+		    __field(int,			ix		)
+		    __array(u8,				anno, 64	)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->call = call;
+		    __entry->ix = ix;
+		    memcpy(__entry->anno, call->rxtx_annotations, 64);
+			   ),
+
+	    TP_printk("c=%p ix=%u a=%64phN",
+		      __entry->call,
+		      __entry->ix,
+		      __entry->anno)
+	    );
+
 #endif /* _TRACE_RXRPC_H */
 
 /* This part must be outside protection */

net/rxrpc/call_event.c

@@ -195,6 +195,7 @@ static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
 	 * the packets in the Tx buffer we're going to resend and what the new
 	 * resend timeout will be.
 	 */
+	trace_rxrpc_resend(call, (cursor + 1) & RXRPC_RXTX_BUFF_MASK);
 	oldest = now;
 	for (seq = cursor + 1; before_eq(seq, top); seq++) {
 		ix = seq & RXRPC_RXTX_BUFF_MASK;