[TCP]: Abstract out all write queue operations.

This allows the write queue implementation to be changed,
for example, to one which allows fast interval searching.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 16 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 3834b10b511..689f9330f1b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -470,10 +470,8 @@ static inline void skb_entail(struct sock *sk, struct tcp_sock *tp,
 	tcb->flags   = TCPCB_FLAG_ACK;
 	tcb->sacked  = 0;
 	skb_header_release(skb);
-	__skb_queue_tail(&sk->sk_write_queue, skb);
+	tcp_add_write_queue_tail(sk, skb);
 	sk_charge_skb(sk, skb);
-	if (!sk->sk_send_head)
-		sk->sk_send_head = skb;
 	if (tp->nonagle & TCP_NAGLE_PUSH)
 		tp->nonagle &= ~TCP_NAGLE_PUSH;
 }
@@ -491,8 +489,8 @@ static inline void tcp_mark_urg(struct tcp_sock *tp, int flags,
 static inline void tcp_push(struct sock *sk, struct tcp_sock *tp, int flags,
 			    int mss_now, int nonagle)
 {
-	if (sk->sk_send_head) {
-		struct sk_buff *skb = sk->sk_write_queue.prev;
+	if (tcp_send_head(sk)) {
+		struct sk_buff *skb = tcp_write_queue_tail(sk);
 		if (!(flags & MSG_MORE) || forced_push(tp))
 			tcp_mark_push(tp, skb);
 		tcp_mark_urg(tp, flags, skb);
@@ -526,13 +524,13 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page **pages, int poffse
 		goto do_error;
 
 	while (psize > 0) {
-		struct sk_buff *skb = sk->sk_write_queue.prev;
+		struct sk_buff *skb = tcp_write_queue_tail(sk);
 		struct page *page = pages[poffset / PAGE_SIZE];
 		int copy, i, can_coalesce;
 		int offset = poffset % PAGE_SIZE;
 		int size = min_t(size_t, psize, PAGE_SIZE - offset);
 
-		if (!sk->sk_send_head || (copy = size_goal - skb->len) <= 0) {
+		if (!tcp_send_head(sk) || (copy = size_goal - skb->len) <= 0) {
 new_segment:
 			if (!sk_stream_memory_free(sk))
 				goto wait_for_sndbuf;
@@ -589,7 +587,7 @@ new_segment:
 		if (forced_push(tp)) {
 			tcp_mark_push(tp, skb);
 			__tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
-		} else if (skb == sk->sk_send_head)
+		} else if (skb == tcp_send_head(sk))
 			tcp_push_one(sk, mss_now);
 		continue;
 
@@ -704,9 +702,9 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 		while (seglen > 0) {
 			int copy;
 
-			skb = sk->sk_write_queue.prev;
+			skb = tcp_write_queue_tail(sk);
 
-			if (!sk->sk_send_head ||
+			if (!tcp_send_head(sk) ||
 			    (copy = size_goal - skb->len) <= 0) {
 
 new_segment:
@@ -833,7 +831,7 @@ new_segment:
 			if (forced_push(tp)) {
 				tcp_mark_push(tp, skb);
 				__tcp_push_pending_frames(sk, tp, mss_now, TCP_NAGLE_PUSH);
-			} else if (skb == sk->sk_send_head)
+			} else if (skb == tcp_send_head(sk))
 				tcp_push_one(sk, mss_now);
 			continue;
 
@@ -860,9 +858,11 @@ out:
 
 do_fault:
 	if (!skb->len) {
-		if (sk->sk_send_head == skb)
-			sk->sk_send_head = NULL;
-		__skb_unlink(skb, &sk->sk_write_queue);
+		tcp_unlink_write_queue(skb, sk);
+		/* It is the one place in all of TCP, except connection
+		 * reset, where we can be unlinking the send_head.
+		 */
+		tcp_check_send_head(sk, skb);
 		sk_stream_free_skb(sk, skb);
 	}
 
@@ -1732,7 +1732,7 @@ int tcp_disconnect(struct sock *sk, int flags)
 
 	tcp_clear_xmit_timers(sk);
 	__skb_queue_purge(&sk->sk_receive_queue);
-	sk_stream_writequeue_purge(sk);
+	tcp_write_queue_purge(sk);
 	__skb_queue_purge(&tp->out_of_order_queue);
 #ifdef CONFIG_NET_DMA
 	__skb_queue_purge(&sk->sk_async_wait_queue);
@@ -1758,7 +1758,7 @@ int tcp_disconnect(struct sock *sk, int flags)
 	tcp_set_ca_state(sk, TCP_CA_Open);
 	tcp_clear_retrans(tp);
 	inet_csk_delack_init(sk);
-	sk->sk_send_head = NULL;
+	tcp_init_send_head(sk);
 	tp->rx_opt.saw_tstamp = 0;
 	tcp_sack_reset(&tp->rx_opt);
 	__sk_dst_reset(sk);