diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 47c74a581a0f..e78c40b37db5 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -498,6 +498,7 @@ struct rxrpc_call {
 	 */
 #define RXRPC_RXTX_BUFF_SIZE	64
 #define RXRPC_RXTX_BUFF_MASK	(RXRPC_RXTX_BUFF_SIZE - 1)
+#define RXRPC_INIT_RX_WINDOW_SIZE 32
 	struct sk_buff		**rxtx_buffer;
 	u8			*rxtx_annotations;
 #define RXRPC_TX_ANNO_ACK	0
@@ -518,7 +519,7 @@ struct rxrpc_call {
 	rxrpc_seq_t		rx_expect_next;	/* Expected next packet sequence number */
 	u8			rx_winsize;	/* Size of Rx window */
 	u8			tx_winsize;	/* Maximum size of Tx window */
-	u8			nr_jumbo_dup;	/* Number of jumbo duplicates */
+	u8			nr_jumbo_bad;	/* Number of jumbo dups/exceeds-windows */
 
 	/* receive-phase ACK management */
 	u8			ackr_reason;	/* reason to ACK */
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 9aa1c4b53563..22f9b0d1a138 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -152,7 +152,7 @@ struct rxrpc_call *rxrpc_alloc_call(gfp_t gfp)
 	memset(&call->sock_node, 0xed, sizeof(call->sock_node));
 
 	/* Leave space in the ring to handle a maxed-out jumbo packet */
-	call->rx_winsize = RXRPC_RXTX_BUFF_SIZE - 1 - 46;
+	call->rx_winsize = rxrpc_rx_window_size;
 	call->tx_winsize = 16;
 	call->rx_expect_next = 1;
 	return call;
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 8e529afcd6c1..75af0bd316c7 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -164,7 +164,7 @@ protocol_error:
  * (that information is encoded in the ACK packet).
  */
 static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
-				 u8 annotation, bool *_jumbo_dup)
+				 u8 annotation, bool *_jumbo_bad)
 {
 	/* Discard normal packets that are duplicates. */
 	if (annotation == 0)
@@ -174,9 +174,9 @@ static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
 	 * more partially duplicate jumbo packets, we refuse to take any more
 	 * jumbos for this call.
 	 */
-	if (!*_jumbo_dup) {
-		call->nr_jumbo_dup++;
-		*_jumbo_dup = true;
+	if (!*_jumbo_bad) {
+		call->nr_jumbo_bad++;
+		*_jumbo_bad = true;
 	}
 }
 
@@ -191,7 +191,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 	unsigned int ix;
 	rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
 	rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
-	bool immediate_ack = false, jumbo_dup = false, queued;
+	bool immediate_ack = false, jumbo_bad = false, queued;
 	u16 len;
 	u8 ack = 0, flags, annotation = 0;
 
@@ -222,7 +222,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb,
 
 	flags = sp->hdr.flags;
 	if (flags & RXRPC_JUMBO_PACKET) {
-		if (call->nr_jumbo_dup > 3) {
+		if (call->nr_jumbo_bad > 3) {
 			ack = RXRPC_ACK_NOSPACE;
 			ack_serial = serial;
 			goto ack;
@@ -259,7 +259,7 @@ next_subpacket:
 	}
 
 	if (call->rxtx_buffer[ix]) {
-		rxrpc_input_dup_data(call, seq, annotation, &jumbo_dup);
+		rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
 		if (ack != RXRPC_ACK_DUPLICATE) {
 			ack = RXRPC_ACK_DUPLICATE;
 			ack_serial = serial;
@@ -304,6 +304,15 @@ skip:
 		annotation++;
 		if (flags & RXRPC_JUMBO_PACKET)
 			annotation |= RXRPC_RX_ANNO_JLAST;
+		if (after(seq, hard_ack + call->rx_winsize)) {
+			ack = RXRPC_ACK_EXCEEDS_WINDOW;
+			ack_serial = serial;
+			if (!jumbo_bad) {
+				call->nr_jumbo_bad++;
+				jumbo_bad = true;
+			}
+			goto ack;
+		}
 
 		_proto("Rx DATA Jumbo %%%u", serial);
 		goto next_subpacket;
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index fd096f742e4b..8b910780f1ac 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -50,7 +50,10 @@ unsigned int rxrpc_idle_ack_delay = 0.5 * HZ;
  * limit is hit, we should generate an EXCEEDS_WINDOW ACK and discard further
  * packets.
  */
-unsigned int rxrpc_rx_window_size = RXRPC_RXTX_BUFF_SIZE - 46;
+unsigned int rxrpc_rx_window_size = RXRPC_INIT_RX_WINDOW_SIZE;
+#if (RXRPC_RXTX_BUFF_SIZE - 1) < RXRPC_INIT_RX_WINDOW_SIZE
+#error Need to reduce RXRPC_INIT_RX_WINDOW_SIZE
+#endif
 
 /*
  * Maximum Rx MTU size.  This indicates to the sender the size of jumbo packet
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 719a4c23f09d..90c7722d5779 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -71,10 +71,10 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
 
 	mtu = call->conn->params.peer->if_mtu;
 	mtu -= call->conn->params.peer->hdrsize;
-	jmax = (call->nr_jumbo_dup > 3) ? 1 : rxrpc_rx_jumbo_max;
+	jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
 	pkt->ackinfo.rxMTU	= htonl(rxrpc_rx_mtu);
 	pkt->ackinfo.maxMTU	= htonl(mtu);
-	pkt->ackinfo.rwind	= htonl(rxrpc_rx_window_size);
+	pkt->ackinfo.rwind	= htonl(call->rx_winsize);
 	pkt->ackinfo.jumbo_max	= htonl(jmax);
 
 	*ackp++ = 0;
diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
index b7ca8cf13c84..a03c61c672f5 100644
--- a/net/rxrpc/sysctl.c
+++ b/net/rxrpc/sysctl.c
@@ -20,7 +20,7 @@ static const unsigned int one = 1;
 static const unsigned int four = 4;
 static const unsigned int thirtytwo = 32;
 static const unsigned int n_65535 = 65535;
-static const unsigned int n_max_acks = RXRPC_MAXACKS;
+static const unsigned int n_max_acks = RXRPC_RXTX_BUFF_SIZE - 1;
 
 /*
  * RxRPC operating parameters.