1 files changed, 27 insertions, 22 deletions

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 2988e3d0c1f6..d0e20e946e48 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -27,7 +27,6 @@ static void rxrpc_congestion_management(struct rxrpc_call *call,
 	enum rxrpc_congest_change change = rxrpc_cong_no_change;
 	unsigned int cumulative_acks = call->cong_cumul_acks;
 	unsigned int cwnd = call->cong_cwnd;
-	ktime_t now;
 	bool resend = false;
 
 	summary->flight_size =
@@ -57,27 +56,6 @@ static void rxrpc_congestion_management(struct rxrpc_call *call,
 	summary->cumulative_acks = cumulative_acks;
 	summary->dup_acks = call->cong_dup_acks;
 
-	/* If we haven't transmitted anything for >1RTT, we should reset the
-	 * congestion management state.
-	 */
-	now = ktime_get_real();
-	if ((call->cong_mode == RXRPC_CALL_SLOW_START ||
-	     call->cong_mode == RXRPC_CALL_CONGEST_AVOIDANCE) &&
-	    ktime_before(ktime_add_us(call->tx_last_sent,
-				      call->peer->srtt_us >> 3), now)
-	    ) {
-		trace_rxrpc_reset_cwnd(call, now);
-		change = rxrpc_cong_idle_reset;
-		rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset);
-		summary->mode = RXRPC_CALL_SLOW_START;
-		if (RXRPC_TX_SMSS > 2190)
-			summary->cwnd = 2;
-		else if (RXRPC_TX_SMSS > 1095)
-			summary->cwnd = 3;
-		else
-			summary->cwnd = 4;
-	}
-
 	switch (call->cong_mode) {
 	case RXRPC_CALL_SLOW_START:
 		if (summary->saw_nacks)
@@ -198,6 +176,33 @@ send_extra_data:
 }
 
 /*
+ * Degrade the congestion window if we haven't transmitted a packet for >1RTT.
+ */
+void rxrpc_congestion_degrade(struct rxrpc_call *call)
+{
+	ktime_t rtt, now;
+
+	if (call->cong_mode != RXRPC_CALL_SLOW_START &&
+	    call->cong_mode != RXRPC_CALL_CONGEST_AVOIDANCE)
+		return;
+	if (call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY)
+		return;
+
+	rtt = ns_to_ktime(call->peer->srtt_us * (1000 / 8));
+	now = ktime_get_real();
+	if (!ktime_before(ktime_add(call->tx_last_sent, rtt), now))
+		return;
+
+	trace_rxrpc_reset_cwnd(call, now);
+	rxrpc_inc_stat(call->rxnet, stat_tx_data_cwnd_reset);
+	call->tx_last_sent = now;
+	call->cong_mode = RXRPC_CALL_SLOW_START;
+	call->cong_ssthresh = max_t(unsigned int, call->cong_ssthresh,
+				    call->cong_cwnd * 3 / 4);
+	call->cong_cwnd = max_t(unsigned int, call->cong_cwnd / 2, RXRPC_MIN_CWND);
+}
+
+/*
  * Apply a hard ACK by advancing the Tx window.
  */
 static bool rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to,