[DCCP] CCID2: Initialize ssthresh to infinity

Initialize the slow-start threshold to infinity.  This way, upon connection
initiation, slow-start will be exited only upon a packet loss.  This patch will
allow connections to quickly gain speed.
Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/ccids/ccid2.c

@@ -678,9 +678,12 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
 	int seqcount = ccid2_seq_len;
 	int i;
 
-	/* XXX init variables with proper values */
 	hctx->ccid2hctx_cwnd	  = 1;
-	hctx->ccid2hctx_ssthresh  = 10;
+	/* Initialize ssthresh to infinity.  This means that we will exit the
+	 * initial slow-start after the first packet loss.  This is what we
+	 * want.
+	 */
+	hctx->ccid2hctx_ssthresh  = ~0;
 	hctx->ccid2hctx_numdupack = 3;
 
 	/* XXX init ~ to window size... */

net/dccp/ccids/ccid2.h

@@ -50,7 +50,7 @@ struct ccid2_hc_tx_sock {
 	int			ccid2hctx_cwnd;
 	int			ccid2hctx_ssacks;
 	int			ccid2hctx_acks;
-	int			ccid2hctx_ssthresh;
+	unsigned int		ccid2hctx_ssthresh;
 	int			ccid2hctx_pipe;
 	int			ccid2hctx_numdupack;
 	struct ccid2_seq	*ccid2hctx_seqbuf;