[DCCP]: Simplify skb_set_owner_w semantics

  
While we're at it let's reorganise the set_owner_w calls a little so that:
  
1) dccp_transmit_skb sets the owner for all packets except data packets.
2) Add dccp_skb_entail to set owner for packets queued for retransmission.
3) Make dccp_transmit_skb static.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

net/dccp/dccp.h

@@ -118,7 +118,6 @@ DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
 #define DCCP_ADD_STATS_USER(field, val)	\
 			SNMP_ADD_STATS_USER(dccp_statistics, field, val)
 
-extern int  dccp_transmit_skb(struct sock *sk, struct sk_buff *skb);
 extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
 
 extern int dccp_send_response(struct sock *sk);

net/dccp/output.c

@@ -12,6 +12,7 @@
 
 #include <linux/config.h>
 #include <linux/dccp.h>
+#include <linux/kernel.h>
 #include <linux/skbuff.h>
 
 #include <net/sock.h>
@@ -25,13 +26,20 @@ static inline void dccp_event_ack_sent(struct sock *sk)
 	inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
 }
 
+static inline void 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;
+}
+
 /*
  * All SKB's seen here are completely headerless. It is our
  * job to build the DCCP header, and pass the packet down to
  * IP so it can do the same plus pass the packet off to the
  * device.
  */
-int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
+static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 {
 	if (likely(skb != NULL)) {
 		const struct inet_sock *inet = inet_sk(sk);
@@ -63,6 +71,9 @@ int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 		skb->h.raw = skb_push(skb, dccp_header_size);
 		dh = dccp_hdr(skb);
 
+		/*
+		 * Only data packets should come through with skb->sk set.
+		 */
 		if (!skb->sk)
 			skb_set_owner_w(skb, sk);
 
@@ -393,10 +404,8 @@ int dccp_connect(struct sock *sk)
 
 	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
 	skb->csum = 0;
-	skb_set_owner_w(skb, sk);
 
-	BUG_TRAP(sk->sk_send_head == NULL);
-	sk->sk_send_head = skb;
+	dccp_skb_entail(sk, skb);
 	dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL));
 	DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS);
 
@@ -425,7 +434,6 @@ void dccp_send_ack(struct sock *sk)
 		skb_reserve(skb, MAX_DCCP_HEADER);
 		skb->csum = 0;
 		DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
-		skb_set_owner_w(skb, sk);
 		dccp_transmit_skb(sk, skb);
 	}
 }
@@ -482,7 +490,6 @@ void dccp_send_sync(struct sock *sk, const u64 seq,
 	DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
 	DCCP_SKB_CB(skb)->dccpd_seq = seq;
 
-	skb_set_owner_w(skb, sk);
 	dccp_transmit_skb(sk, skb);
 }
 
@@ -507,10 +514,8 @@ void dccp_send_close(struct sock *sk, const int active)
 	DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
 					DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
 
-	skb_set_owner_w(skb, sk);
 	if (active) {
-		BUG_TRAP(sk->sk_send_head == NULL);
-		sk->sk_send_head = skb;
+		dccp_skb_entail(sk, skb);
 		dccp_transmit_skb(sk, skb_clone(skb, prio));
 	} else
 		dccp_transmit_skb(sk, skb);