diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index cb174f699665..5039613ad0e1 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -667,7 +667,6 @@ struct rxrpc_call {
 
 	/* Receive-phase ACK management (ACKs we send). */
 	u8			ackr_reason;	/* reason to ACK */
-	rxrpc_serial_t		ackr_serial;	/* serial of packet being ACK'd */
 	rxrpc_seq_t		ackr_highest_seq; /* Higest sequence number received */
 	atomic_t		ackr_nr_unacked; /* Number of unacked packets */
 	atomic_t		ackr_nr_consumed; /* Number of packets needing hard ACK */
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index b5f173960725..c08715be8e9a 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -67,13 +67,11 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 	if (ack_reason == call->ackr_reason) {
 		if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {
 			outcome = rxrpc_propose_ack_update;
-			call->ackr_serial = serial;
 		}
 		if (!immediate)
 			goto trace;
 	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {
 		call->ackr_reason = ack_reason;
-		call->ackr_serial = serial;
 	} else {
 		outcome = rxrpc_propose_ack_subsume;
 	}
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 09fcc54245c7..8816aaa98287 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -87,7 +87,7 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn,
 		return 0;
 
 	/* Barrier against rxrpc_input_data(). */
-	serial = call->ackr_serial;
+	serial = 0;
 	hard_ack = READ_ONCE(call->rx_hard_ack);
 	top = smp_load_acquire(&call->rx_top);
 	*_hard_ack = hard_ack;