[DCCP]: Wait for CCID

This performs a minor optimisation: when ccid_hc_tx_send_packet
returns a value greater zero, then the same call previously was done
again at the begin of the while loop in dccp_wait_for_ccid.

This patch exploits the available information and schedule-timeouts
directly instead.

Documentation also added.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dccp/output.c b/net/dccp/output.c
index 6a334ed..f495446 100644 (file)
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -177,34 +177,38 @@ void dccp_write_space(struct sock *sk)
 
 /**
  * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet
- * @sk: socket to wait for
+ * @sk:    socket to wait for
+ * @skb:   current skb to pass on for waiting
+ * @delay: sleep timeout in milliseconds (> 0)
+ * This function is called by default when the socket is closed, and
+ * when a non-zero linger time is set on the socket. For consistency
  */
-static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb)
+static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay)
 {
        struct dccp_sock *dp = dccp_sk(sk);
        DEFINE_WAIT(wait);
-       unsigned long delay;
+       unsigned long jiffdelay;
        int rc;
 
-       while (1) {
+       do {
+               dccp_pr_debug("delayed send by %d msec\n", delay);
+               jiffdelay = msecs_to_jiffies(delay);
+
                prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
 
+               sk->sk_write_pending++;
+               release_sock(sk);
+               schedule_timeout(jiffdelay);
+               lock_sock(sk);
+               sk->sk_write_pending--;
+
                if (sk->sk_err)
                        goto do_error;
                if (signal_pending(current))
                        goto do_interrupted;
 
                rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb);
-               if (rc <= 0)
-                       break;
-               dccp_pr_debug("delayed send by %d msec\n", rc);
-               delay = msecs_to_jiffies(rc);
-               sk->sk_write_pending++;
-               release_sock(sk);
-               schedule_timeout(delay);
-               lock_sock(sk);
-               sk->sk_write_pending--;
-       }
+       } while ((delay = rc) > 0);
 out:
        finish_wait(sk->sk_sleep, &wait);
        return rc;
@@ -231,7 +235,7 @@ void dccp_write_xmit(struct sock *sk, int block)
                                                msecs_to_jiffies(err)+jiffies);
                                break;
                        } else
-                               err = dccp_wait_for_ccid(sk, skb);
+                               err = dccp_wait_for_ccid(sk, skb, err);
                        if (err && err != -EINTR)
                                DCCP_BUG("err=%d after dccp_wait_for_ccid", err);
                }