[CCID3]: Call sk->sk_write_space(sk) when receiving a feedback packet

This makes the send rate calculations behave way more closely to what
is specified, with the jitter previously seen on x and x_recv
disappearing completely on non lossy setups.

This resembles the tcp_data_snd_check code, that possibly we'll end up
using in DCCP as well, perhaps moving this code to
inet_connection_sock.

For now I'm doing the simplest implementation tho.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index e22b0ee..7bf3b3a 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -556,6 +556,11 @@
 		/* remove all packets older than the one acked from history */
 		dccp_tx_hist_purge_older(ccid3_tx_hist,
 					 &hctx->ccid3hctx_hist, packet);
+		/*
+		 * As we have calculated new ipi, delta, t_nom it is possible that
+		 * we now can send a packet, so wake up dccp_wait_for_ccids.
+		 */
+		sk->sk_write_space(sk);
 
 		/*
 		 * Schedule no feedback timer to expire in