[PATCH 6.6 009/112] rxrpc: Fix RTT determination to use any ACK as a source

[PATCH 6.6 009/112] rxrpc: Fix RTT determination to use any ACK as a source

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 3798680f2fbbe0ca3ab6138b34e0d161c36497ee ]

Fix RTT determination to be able to use any type of ACK as the response
from which RTT can be calculated provided its ack.serial is non-zero and
matches the serial number of an outgoing DATA or ACK packet.  This
shouldn't be limited to REQUESTED-type ACKs as these can have other types
substituted for them for things like duplicate or out-of-order packets.

Fixes: 4700c4d80b7b ("rxrpc: Fix loss of RTT samples due to interposed ACK")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/trace/events/rxrpc.h |  2 +-
 net/rxrpc/input.c            | 35 ++++++++++++++++-------------------
 2 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 4c53a5ef6257b..f7e537f64db45 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -328,7 +328,7 @@
 	E_(rxrpc_rtt_tx_ping,			"PING")
 
 #define rxrpc_rtt_rx_traces \
-	EM(rxrpc_rtt_rx_cancel,			"CNCL") \
+	EM(rxrpc_rtt_rx_other_ack,		"OACK") \
 	EM(rxrpc_rtt_rx_obsolete,		"OBSL") \
 	EM(rxrpc_rtt_rx_lost,			"LOST") \
 	EM(rxrpc_rtt_rx_ping_response,		"PONG") \
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 030d64f282f37..3f9594d125192 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -643,12 +643,8 @@ static void rxrpc_complete_rtt_probe(struct rxrpc_call *call,
 			clear_bit(i + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail);
 			smp_mb(); /* Read data before setting avail bit */
 			set_bit(i, &call->rtt_avail);
-			if (type != rxrpc_rtt_rx_cancel)
-				rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
-						   sent_at, resp_time);
-			else
-				trace_rxrpc_rtt_rx(call, rxrpc_rtt_rx_cancel, i,
-						   orig_serial, acked_serial, 0, 0);
+			rxrpc_peer_add_rtt(call, type, i, acked_serial, ack_serial,
+					   sent_at, resp_time);
 			matched = true;
 		}
 
@@ -801,20 +797,21 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 			   summary.ack_reason, nr_acks);
 	rxrpc_inc_stat(call->rxnet, stat_rx_acks[ack.reason]);
 
-	switch (ack.reason) {
-	case RXRPC_ACK_PING_RESPONSE:
-		rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
-					 rxrpc_rtt_rx_ping_response);
-		break;
-	case RXRPC_ACK_REQUESTED:
-		rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
-					 rxrpc_rtt_rx_requested_ack);
-		break;
-	default:
-		if (acked_serial != 0)
+	if (acked_serial != 0) {
+		switch (ack.reason) {
+		case RXRPC_ACK_PING_RESPONSE:
 			rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
-						 rxrpc_rtt_rx_cancel);
-		break;
+						 rxrpc_rtt_rx_ping_response);
+			break;
+		case RXRPC_ACK_REQUESTED:
+			rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
+						 rxrpc_rtt_rx_requested_ack);
+			break;
+		default:
+			rxrpc_complete_rtt_probe(call, skb->tstamp, acked_serial, ack_serial,
+						 rxrpc_rtt_rx_other_ack);
+			break;
+		}
 	}
 
 	if (ack.reason == RXRPC_ACK_PING) {
-- 
2.42.0

[PATCH 6.6 010/112] rxrpc: Defer the response to a PING ACK until weve parsed it

[Greg Kroah-Hartman]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 1a01319feef7047aa2ba400ffa3e047776aa29ca ]

Defer the generation of a PING RESPONSE ACK in response to a PING ACK until
we've parsed the PING ACK so that we pick up any changes to the packet
queue so that we can update ackinfo.

This is also applied to an ACK generated in response to an ACK with the
REQUEST_ACK flag set.

Note that whilst the problem was added in commit 248f219cb8bc, it didn't
really matter at that point because the ACK was proposed in softirq mode
and generated asynchronously later in process context, taking the latest
values at the time.  But this fix is only needed since the move to parse
incoming packets in an I/O thread rather than in softirq and generate the
ACK at point of proposal (b0346843b1076b34a0278ff601f8f287535cb064).

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/rxrpc/input.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 3f9594d125192..92495e73b8699 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -814,14 +814,6 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 		}
 	}
 
-	if (ack.reason == RXRPC_ACK_PING) {
-		rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
-			       rxrpc_propose_ack_respond_to_ping);
-	} else if (sp->hdr.flags & RXRPC_REQUEST_ACK) {
-		rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
-			       rxrpc_propose_ack_respond_to_ack);
-	}
-
 	/* If we get an EXCEEDS_WINDOW ACK from the server, it probably
 	 * indicates that the client address changed due to NAT.  The server
 	 * lost the call because it switched to a different peer.
@@ -832,7 +824,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	    rxrpc_is_client_call(call)) {
 		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 					  0, -ENETRESET);
-		return;
+		goto send_response;
 	}
 
 	/* If we get an OUT_OF_SEQUENCE ACK from the server, that can also
@@ -846,7 +838,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	    rxrpc_is_client_call(call)) {
 		rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 					  0, -ENETRESET);
-		return;
+		goto send_response;
 	}
 
 	/* Discard any out-of-order or duplicate ACKs (outside lock). */
@@ -854,7 +846,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 		trace_rxrpc_rx_discard_ack(call->debug_id, ack_serial,
 					   first_soft_ack, call->acks_first_seq,
 					   prev_pkt, call->acks_prev_seq);
-		return;
+		goto send_response;
 	}
 
 	info.rxMTU = 0;
@@ -894,7 +886,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	case RXRPC_CALL_SERVER_AWAIT_ACK:
 		break;
 	default:
-		return;
+		goto send_response;
 	}
 
 	if (before(hard_ack, call->acks_hard_ack) ||
@@ -906,7 +898,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 	if (after(hard_ack, call->acks_hard_ack)) {
 		if (rxrpc_rotate_tx_window(call, hard_ack, &summary)) {
 			rxrpc_end_tx_phase(call, false, rxrpc_eproto_unexpected_ack);
-			return;
+			goto send_response;
 		}
 	}
 
@@ -924,6 +916,14 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb)
 				   rxrpc_propose_ack_ping_for_lost_reply);
 
 	rxrpc_congestion_management(call, skb, &summary, acked_serial);
+
+send_response:
+	if (ack.reason == RXRPC_ACK_PING)
+		rxrpc_send_ACK(call, RXRPC_ACK_PING_RESPONSE, ack_serial,
+			       rxrpc_propose_ack_respond_to_ping);
+	else if (sp->hdr.flags & RXRPC_REQUEST_ACK)
+		rxrpc_send_ACK(call, RXRPC_ACK_REQUESTED, ack_serial,
+			       rxrpc_propose_ack_respond_to_ack);
 }
 
 /*
-- 
2.42.0