rxrpc: Reduce ssthresh to peer's receive window

When we receive an ACK from the peer that tells us what the peer's receive
window (rwind) is, we should reduce ssthresh to rwind if rwind is smaller
than ssthresh.

Signed-off-by: David Howells <dhowells@redhat.com>


diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 21746f0..7993473 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -658,6 +658,8 @@
 	if (rwind > RXRPC_RXTX_BUFF_SIZE - 1)
 		rwind = RXRPC_RXTX_BUFF_SIZE - 1;
 	call->tx_winsize = rwind;
+	if (call->cong_ssthresh > rwind)
+		call->cong_ssthresh = rwind;
 
 	mtu = min(ntohl(ackinfo->rxMTU), ntohl(ackinfo->maxMTU));