[PATCH net-next 6/7] rxrpc: Trace changes in a call's receive window size

[David Howells]

Add a tracepoint (rxrpc_rx_rwind_change) to log changes in a call's receive
window size as imposed by the peer through an ACK packet.

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

 include/trace/events/rxrpc.h |   27 +++++++++++++++++++++++++++
 net/rxrpc/input.c            |    2 ++
 2 files changed, 29 insertions(+)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 85e0148c88a8..15ba7387c243 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -707,6 +707,33 @@ TRACE_EVENT(rxrpc_rx_abort,
                      __entry->abort_code)
            );
 
+TRACE_EVENT(rxrpc_rx_rwind_change,
+           TP_PROTO(struct rxrpc_call *call, rxrpc_serial_t serial,
+                    u32 rwind, bool wake),
+
+           TP_ARGS(call, serial, rwind, wake),
+
+           TP_STRUCT__entry(
+                   __field(struct rxrpc_call *,        call            )
+                   __field(rxrpc_serial_t,             serial          )
+                   __field(u32,                        rwind           )
+                   __field(bool,                       wake            )
+                            ),
+
+           TP_fast_assign(
+                   __entry->call = call;
+                   __entry->serial = serial;
+                   __entry->rwind = rwind;
+                   __entry->wake = wake;
+                          ),
+
+           TP_printk("c=%p %08x rw=%u%s",
+                     __entry->call,
+                     __entry->serial,
+                     __entry->rwind,
+                     __entry->wake ? " wake" : "")
+           );
+
 TRACE_EVENT(rxrpc_tx_data,
            TP_PROTO(struct rxrpc_call *call, rxrpc_seq_t seq,
                     rxrpc_serial_t serial, u8 flags, bool retrans, bool lose),
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 241e989597f2..45dba732a3b4 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -665,6 +665,8 @@ static void rxrpc_input_ackinfo(struct rxrpc_call *call, 
struct sk_buff *skb,
                        rwind = RXRPC_RXTX_BUFF_SIZE - 1;
                if (rwind > call->tx_winsize)
                        wake = true;
+               trace_rxrpc_rx_rwind_change(call, sp->hdr.serial,
+                                           ntohl(ackinfo->rwind), wake);
                call->tx_winsize = rwind;
        }