[DCCP]: Introduce dccp_wait_for_ccid and use it in dccp_write_xmit

This is not quite what I think we should have long term but improves
performance for now, so lets use it till we get CCID3 working well,
then we can think about using sk_write_queue, perhaps using some ideas
from Juwen Lai's old stack for 2.4.20.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 59 insertions, 2 deletions

diff --git a/net/dccp/output.c b/net/dccp/output.c
index f96dedd..116f6db5 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -150,14 +150,71 @@ unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu)
 	return mss_now;
 }
 
-int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, const int len)
+/**
+ * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
+ * @sk: socket to wait for
+ * @timeo: for how long
+ */
+static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
+			      long *timeo)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	DEFINE_WAIT(wait);
+	long delay;
+	int rc;
+
+	while (1) {
+		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+
+		if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+			goto do_error;
+		if (!*timeo)
+			goto do_nonblock;
+		if (signal_pending(current))
+			goto do_interrupted;
+
+		rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
+					    skb->len);
+		if (rc <= 0)
+			break;
+		delay = msecs_to_jiffies(rc);
+		if (delay > *timeo || delay < 0)
+			goto do_nonblock;
+
+		sk->sk_write_pending++;
+		release_sock(sk);
+		*timeo -= schedule_timeout(delay);
+		lock_sock(sk);
+		sk->sk_write_pending--;
+	}
+out:
+	finish_wait(sk->sk_sleep, &wait);
+	return rc;
+
+do_error:
+	rc = -EPIPE;
+	goto out;
+do_nonblock:
+	rc = -EAGAIN;
+	goto out;
+do_interrupted:
+	rc = sock_intr_errno(*timeo);
+	goto out;
+}
+
+int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
 {
 	const struct dccp_sock *dp = dccp_sk(sk);
-	int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb, len);
+	int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
+					 skb->len);
+
+	if (err > 0)
+		err = dccp_wait_for_ccid(sk, skb, timeo);
 
 	if (err == 0) {
 		const struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
 		struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+		const int len = skb->len;
 
 		if (sk->sk_state == DCCP_PARTOPEN) {
 			/* See 8.1.5.  Handshake Completion */