rxrpc: Trace discarded ACKs

Add a tracepoint to track received ACKs that are discarded due to being
outside of the Tx window.

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

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index ab75f261f04a9672aec40c1793976eed16cc4c90..ba9efdc848f970b1b05e9fd0a30091a37159029c 100644 (file)
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -1541,6 +1541,41 @@ TRACE_EVENT(rxrpc_notify_socket,
                      __entry->serial)
            );
 
+TRACE_EVENT(rxrpc_rx_discard_ack,
+           TP_PROTO(unsigned int debug_id, rxrpc_serial_t serial,
+                    rxrpc_seq_t first_soft_ack, rxrpc_seq_t call_ackr_first,
+                    rxrpc_seq_t prev_pkt, rxrpc_seq_t call_ackr_prev),
+
+           TP_ARGS(debug_id, serial, first_soft_ack, call_ackr_first,
+                   prev_pkt, call_ackr_prev),
+
+           TP_STRUCT__entry(
+                   __field(unsigned int,       debug_id        )
+                   __field(rxrpc_serial_t,     serial          )
+                   __field(rxrpc_seq_t,        first_soft_ack)
+                   __field(rxrpc_seq_t,        call_ackr_first)
+                   __field(rxrpc_seq_t,        prev_pkt)
+                   __field(rxrpc_seq_t,        call_ackr_prev)
+                            ),
+
+           TP_fast_assign(
+                   __entry->debug_id           = debug_id;
+                   __entry->serial             = serial;
+                   __entry->first_soft_ack     = first_soft_ack;
+                   __entry->call_ackr_first    = call_ackr_first;
+                   __entry->prev_pkt           = prev_pkt;
+                   __entry->call_ackr_prev     = call_ackr_prev;
+                          ),
+
+           TP_printk("c=%08x r=%08x %08x<%08x %08x<%08x",
+                     __entry->debug_id,
+                     __entry->serial,
+                     __entry->first_soft_ack,
+                     __entry->call_ackr_first,
+                     __entry->prev_pkt,
+                     __entry->call_ackr_prev)
+           );
+
 #endif /* _TRACE_RXRPC_H */
 
 /* This part must be outside protection */

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index e438bfd3fdf55864930a1a7f63221fd9898aaa11..2f22f082a66cfc4620bc06bcb224588dd7a27cea 100644 (file)
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -866,8 +866,12 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 
        /* Discard any out-of-order or duplicate ACKs (outside lock). */
        if (before(first_soft_ack, call->ackr_first_seq) ||
-           before(prev_pkt, call->ackr_prev_seq))
+           before(prev_pkt, call->ackr_prev_seq)) {
+               trace_rxrpc_rx_discard_ack(call->debug_id, sp->hdr.serial,
+                                          first_soft_ack, call->ackr_first_seq,
+                                          prev_pkt, call->ackr_prev_seq);
                return;
+       }
 
        buf.info.rxMTU = 0;
        ioffset = offset + nr_acks + 3;
@@ -879,8 +883,12 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 
        /* Discard any out-of-order or duplicate ACKs (inside lock). */
        if (before(first_soft_ack, call->ackr_first_seq) ||
-           before(prev_pkt, call->ackr_prev_seq))
+           before(prev_pkt, call->ackr_prev_seq)) {
+               trace_rxrpc_rx_discard_ack(call->debug_id, sp->hdr.serial,
+                                          first_soft_ack, call->ackr_first_seq,
+                                          prev_pkt, call->ackr_prev_seq);
                goto out;
+       }
        call->acks_latest_ts = skb->tstamp;
 
        call->ackr_first_seq = first_soft_ack;