[PATCH AUTOSEL 5.6 200/606] rxrpc: Trace discarded ACKs

Sasha Levin
2020-06-09T00:29:15Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit d1f129470e6cb79b8b97fecd12689f6eb49e27fe ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/trace/events/rxrpc.h | 35 +++++++++++++++++++++++++++++++++++
net/rxrpc/input.c | 12 ++++++++++--
2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index ab75f261f04a..ba9efdc848f9 100644
--- 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 e438bfd3fdf5..2f22f082a66c 100644
--- 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;
--
2.25.1