[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 3834b10b5115..689f9330f1b9 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);