dccp: Combine the functionality of enqeueing and cloning

Realising the following call pattern,
 * first dccp_entail() is called to enqueue a new skb and
 * then skb_clone() is called to transmit a clone of that skb,

this patch integrates both interrelated steps into dccp_entail().

Note: the return value of skb_clone is not checked. It may be an idea to add a
      warning if this occurs. In both instances, however, a timer is set for
      retransmission, so that cloning is re-tried via dccp_retransmit_skb().

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

diff --git a/net/dccp/output.c b/net/dccp/output.c
index 39056dc..b1eaf7b 100644 (file)
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -26,11 +26,13 @@ static inline void dccp_event_ack_sent(struct sock *sk)
        inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 }
 
-static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
+/* enqueue @skb on sk_send_head for retransmission, return clone to send now */
+static struct sk_buff *dccp_skb_entail(struct sock *sk, struct sk_buff *skb)
 {
        skb_set_owner_w(skb, sk);
        WARN_ON(sk->sk_send_head);
        sk->sk_send_head = skb;
+       return skb_clone(sk->sk_send_head, gfp_any());
 }
 
 /*
@@ -550,8 +552,7 @@ int dccp_connect(struct sock *sk)
 
        DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
 
-       dccp_skb_entail(sk, skb);
-       dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
+       dccp_transmit_skb(sk, dccp_skb_entail(sk, skb));
        DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
 
        /* Timer for repeating the REQUEST until an answer. */
@@ -676,8 +677,7 @@ void dccp_send_close(struct sock *sk, const int active)
                DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE;
 
        if (active) {
-               dccp_skb_entail(sk, skb);
-               dccp_transmit_skb(sk, skb_clone(skb, prio));
+               skb = dccp_skb_entail(sk, skb);
                /*
                 * Retransmission timer for active-close: RFC 4340, 8.3 requires
                 * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ
@@ -690,6 +690,6 @@ void dccp_send_close(struct sock *sk, const int active)
                 */
                inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
                                          DCCP_TIMEOUT_INIT, DCCP_RTO_MAX);
-       } else
-               dccp_transmit_skb(sk, skb);
+       }
+       dccp_transmit_skb(sk, skb);
 }