[PATCH 6.6 066/121] rxrpc: Fix delayed ACKs to not set the reference serial number

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

From: David Howells <dhowells@redhat.com>

[ Upstream commit e7870cf13d20f56bfc19f9c3e89707c69cf104ef ]

Fix the construction of delayed ACKs to not set the reference serial number
as they can't be used as an RTT reference.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
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/ar-internal.h | 1 -
 net/rxrpc/call_event.c  | 6 +-----
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 668fdc94b299..f6375772fa93 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -692,7 +692,6 @@ struct rxrpc_call {
 	/* Receive-phase ACK management (ACKs we send). */
 	u8			ackr_reason;	/* reason to ACK */
 	u16			ackr_sack_base;	/* Starting slot in SACK table ring */
-	rxrpc_serial_t		ackr_serial;	/* serial of packet being ACK'd */
 	rxrpc_seq_t		ackr_window;	/* Base of SACK window */
 	rxrpc_seq_t		ackr_wtop;	/* Base of SACK window */
 	unsigned int		ackr_nr_unacked; /* Number of unacked packets */
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index e363f21a2014..c61efe08695d 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -43,8 +43,6 @@ void rxrpc_propose_delay_ACK(struct rxrpc_call *call, rxrpc_serial_t serial,
 	unsigned long expiry = rxrpc_soft_ack_delay;
 	unsigned long now = jiffies, ack_at;
 
-	call->ackr_serial = serial;
-
 	if (rxrpc_soft_ack_delay < expiry)
 		expiry = rxrpc_soft_ack_delay;
 	if (call->peer->srtt_us != 0)
@@ -373,7 +371,6 @@ static void rxrpc_send_initial_ping(struct rxrpc_call *call)
 bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	unsigned long now, next, t;
-	rxrpc_serial_t ackr_serial;
 	bool resend = false, expired = false;
 	s32 abort_code;
 
@@ -423,8 +420,7 @@ bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb)
 	if (time_after_eq(now, t)) {
 		trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);
 		cmpxchg(&call->delay_ack_at, t, now + MAX_JIFFY_OFFSET);
-		ackr_serial = xchg(&call->ackr_serial, 0);
-		rxrpc_send_ACK(call, RXRPC_ACK_DELAY, ackr_serial,
+		rxrpc_send_ACK(call, RXRPC_ACK_DELAY, 0,
 			       rxrpc_propose_ack_ping_for_lost_ack);
 	}
 
-- 
2.43.0