raw: avoid two atomics in xmit

Avoid two atomic ops per raw_send_hdrinc() call

Avoid two atomic ops per raw6_send_hdrinc() call

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Eric Dumazet

net/ipv4/raw.c

@@ -314,7 +314,7 @@ int raw_rcv(struct sock *sk, struct sk_buff *skb)
 }
 
 static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
-			struct rtable *rt,
+			struct rtable **rtp,
 			unsigned int flags)
 {
 	struct inet_sock *inet = inet_sk(sk);
@@ -323,6 +323,7 @@ static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
 	struct sk_buff *skb;
 	unsigned int iphlen;
 	int err;
+	struct rtable *rt = *rtp;
 
 	if (length > rt->u.dst.dev->mtu) {
 		ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->inet_dport,
@@ -341,7 +342,8 @@ static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
 
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
-	skb_dst_set(skb, dst_clone(&rt->u.dst));
+	skb_dst_set(skb, &rt->u.dst);
+	*rtp = NULL;
 
 	skb_reset_network_header(skb);
 	iph = ip_hdr(skb);
@@ -576,7 +578,7 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 
 	if (inet->hdrincl)
 		err = raw_send_hdrinc(sk, msg->msg_iov, len,
-					rt, msg->msg_flags);
+					&rt, msg->msg_flags);
 
 	 else {
 		if (!ipc.addr)

net/ipv6/raw.c

@@ -602,13 +602,14 @@ static int rawv6_push_pending_frames(struct sock *sk, struct flowi *fl,
 }
 
 static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
-			struct flowi *fl, struct rt6_info *rt,
+			struct flowi *fl, struct dst_entry **dstp,
 			unsigned int flags)
 {
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct ipv6hdr *iph;
 	struct sk_buff *skb;
 	int err;
+	struct rt6_info *rt = (struct rt6_info *)*dstp;
 
 	if (length > rt->u.dst.dev->mtu) {
 		ipv6_local_error(sk, EMSGSIZE, fl, rt->u.dst.dev->mtu);
@@ -626,7 +627,8 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
 
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
-	skb_dst_set(skb, dst_clone(&rt->u.dst));
+	skb_dst_set(skb, &rt->u.dst);
+	*dstp = NULL;
 
 	skb_put(skb, length);
 	skb_reset_network_header(skb);
@@ -886,9 +888,9 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 		goto do_confirm;
 
 back_from_confirm:
-	if (inet->hdrincl) {
-		err = rawv6_send_hdrinc(sk, msg->msg_iov, len, &fl, (struct rt6_info*)dst, msg->msg_flags);
-	} else {
+	if (inet->hdrincl)
+		err = rawv6_send_hdrinc(sk, msg->msg_iov, len, &fl, &dst, msg->msg_flags);
+	else {
 		lock_sock(sk);
 		err = ip6_append_data(sk, ip_generic_getfrag, msg->msg_iov,
 			len, 0, hlimit, tclass, opt, &fl, (struct rt6_info*)dst,