tcp: Use SKB queue and list helpers instead of doing it by-hand.
David S. Miller [Fri, 29 May 2009 04:35:47 +0000 (21:35 -0700)]
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp.c
net/ipv4/tcp_input.c

index 0fb8b44..17b89c5 100644 (file)
@@ -439,12 +439,14 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
                         !tp->urg_data ||
                         before(tp->urg_seq, tp->copied_seq) ||
                         !before(tp->urg_seq, tp->rcv_nxt)) {
+                       struct sk_buff *skb;
+
                        answ = tp->rcv_nxt - tp->copied_seq;
 
                        /* Subtract 1, if FIN is in queue. */
-                       if (answ && !skb_queue_empty(&sk->sk_receive_queue))
-                               answ -=
-                      tcp_hdr((struct sk_buff *)sk->sk_receive_queue.prev)->fin;
+                       skb = skb_peek_tail(&sk->sk_receive_queue);
+                       if (answ && skb)
+                               answ -= tcp_hdr(skb)->fin;
                } else
                        answ = tp->urg_seq - tp->copied_seq;
                release_sock(sk);
@@ -1382,11 +1384,7 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 
                /* Next get a buffer. */
 
-               skb = skb_peek(&sk->sk_receive_queue);
-               do {
-                       if (!skb)
-                               break;
-
+               skb_queue_walk(&sk->sk_receive_queue, skb) {
                        /* Now that we have two receive queues this
                         * shouldn't happen.
                         */
@@ -1403,8 +1401,7 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                        if (tcp_hdr(skb)->fin)
                                goto found_fin_ok;
                        WARN_ON(!(flags & MSG_PEEK));
-                       skb = skb->next;
-               } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
+               }
 
                /* Well, if we have backlog, try to process it now yet. */
 
index eeb8a92..ba34a23 100644 (file)
@@ -4426,7 +4426,7 @@ drop:
                }
                __skb_queue_head(&tp->out_of_order_queue, skb);
        } else {
-               struct sk_buff *skb1 = tp->out_of_order_queue.prev;
+               struct sk_buff *skb1 = skb_peek_tail(&tp->out_of_order_queue);
                u32 seq = TCP_SKB_CB(skb)->seq;
                u32 end_seq = TCP_SKB_CB(skb)->end_seq;
 
@@ -4443,15 +4443,18 @@ drop:
                }
 
                /* Find place to insert this segment. */
-               do {
+               while (1) {
                        if (!after(TCP_SKB_CB(skb1)->seq, seq))
                                break;
-               } while ((skb1 = skb1->prev) !=
-                        (struct sk_buff *)&tp->out_of_order_queue);
+                       if (skb_queue_is_first(&tp->out_of_order_queue, skb1)) {
+                               skb1 = NULL;
+                               break;
+                       }
+                       skb1 = skb_queue_prev(&tp->out_of_order_queue, skb1);
+               }
 
                /* Do skb overlap to previous one? */
-               if (skb1 != (struct sk_buff *)&tp->out_of_order_queue &&
-                   before(seq, TCP_SKB_CB(skb1)->end_seq)) {
+               if (skb1 && before(seq, TCP_SKB_CB(skb1)->end_seq)) {
                        if (!after(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
                                /* All the bits are present. Drop. */
                                __kfree_skb(skb);
@@ -4463,24 +4466,41 @@ drop:
                                tcp_dsack_set(sk, seq,
                                              TCP_SKB_CB(skb1)->end_seq);
                        } else {
-                               skb1 = skb1->prev;
+                               if (skb_queue_is_first(&tp->out_of_order_queue,
+                                                      skb1))
+                                       skb1 = NULL;
+                               else
+                                       skb1 = skb_queue_prev(
+                                               &tp->out_of_order_queue,
+                                               skb1);
                        }
                }
-               __skb_queue_after(&tp->out_of_order_queue, skb1, skb);
+               if (!skb1)
+                       __skb_queue_head(&tp->out_of_order_queue, skb);
+               else
+                       __skb_queue_after(&tp->out_of_order_queue, skb1, skb);
 
                /* And clean segments covered by new one as whole. */
-               while ((skb1 = skb->next) !=
-                      (struct sk_buff *)&tp->out_of_order_queue &&
-                      after(end_seq, TCP_SKB_CB(skb1)->seq)) {
-                       if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) {
+               if (skb1 && !skb_queue_is_last(&tp->out_of_order_queue, skb1)) {
+                       struct sk_buff *n;
+
+                       skb1 = skb_queue_next(&tp->out_of_order_queue, skb1);
+                       skb_queue_walk_from_safe(&tp->out_of_order_queue,
+                                                skb1, n) {
+                               if (!after(end_seq, TCP_SKB_CB(skb1)->seq))
+                                       break;
+                               if (before(end_seq,
+                                          TCP_SKB_CB(skb1)->end_seq)) {
+                                       tcp_dsack_extend(sk,
+                                                        TCP_SKB_CB(skb1)->seq,
+                                                        end_seq);
+                                       break;
+                               }
+                               __skb_unlink(skb1, &tp->out_of_order_queue);
                                tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
-                                                end_seq);
-                               break;
+                                                TCP_SKB_CB(skb1)->end_seq);
+                               __kfree_skb(skb1);
                        }
-                       __skb_unlink(skb1, &tp->out_of_order_queue);
-                       tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq,
-                                        TCP_SKB_CB(skb1)->end_seq);
-                       __kfree_skb(skb1);
                }
 
 add_sack:
@@ -4492,7 +4512,10 @@ add_sack:
 static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb,
                                        struct sk_buff_head *list)
 {
-       struct sk_buff *next = skb->next;
+       struct sk_buff *next = NULL;
+
+       if (!skb_queue_is_last(list, skb))
+               next = skb_queue_next(list, skb);
 
        __skb_unlink(skb, list);
        __kfree_skb(skb);
@@ -4503,6 +4526,9 @@ static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb,
 
 /* Collapse contiguous sequence of skbs head..tail with
  * sequence numbers start..end.
+ *
+ * If tail is NULL, this means until the end of the list.
+ *
  * Segments with FIN/SYN are not collapsed (only because this
  * simplifies code)
  */
@@ -4511,15 +4537,23 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list,
             struct sk_buff *head, struct sk_buff *tail,
             u32 start, u32 end)
 {
-       struct sk_buff *skb;
+       struct sk_buff *skb, *n;
+       bool end_of_skbs;
 
        /* First, check that queue is collapsible and find
         * the point where collapsing can be useful. */
-       for (skb = head; skb != tail;) {
+       skb = head;
+restart:
+       end_of_skbs = true;
+       skb_queue_walk_from_safe(list, skb, n) {
+               if (skb == tail)
+                       break;
                /* No new bits? It is possible on ofo queue. */
                if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
                        skb = tcp_collapse_one(sk, skb, list);
-                       continue;
+                       if (!skb)
+                               break;
+                       goto restart;
                }
 
                /* The first skb to collapse is:
@@ -4529,16 +4563,24 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list,
                 */
                if (!tcp_hdr(skb)->syn && !tcp_hdr(skb)->fin &&
                    (tcp_win_from_space(skb->truesize) > skb->len ||
-                    before(TCP_SKB_CB(skb)->seq, start) ||
-                    (skb->next != tail &&
-                     TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb->next)->seq)))
+                    before(TCP_SKB_CB(skb)->seq, start))) {
+                       end_of_skbs = false;
                        break;
+               }
+
+               if (!skb_queue_is_last(list, skb)) {
+                       struct sk_buff *next = skb_queue_next(list, skb);
+                       if (next != tail &&
+                           TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(next)->seq) {
+                               end_of_skbs = false;
+                               break;
+                       }
+               }
 
                /* Decided to skip this, advance start seq. */
                start = TCP_SKB_CB(skb)->end_seq;
-               skb = skb->next;
        }
-       if (skb == tail || tcp_hdr(skb)->syn || tcp_hdr(skb)->fin)
+       if (end_of_skbs || tcp_hdr(skb)->syn || tcp_hdr(skb)->fin)
                return;
 
        while (before(start, end)) {
@@ -4583,7 +4625,8 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list,
                        }
                        if (!before(start, TCP_SKB_CB(skb)->end_seq)) {
                                skb = tcp_collapse_one(sk, skb, list);
-                               if (skb == tail ||
+                               if (!skb ||
+                                   skb == tail ||
                                    tcp_hdr(skb)->syn ||
                                    tcp_hdr(skb)->fin)
                                        return;
@@ -4610,17 +4653,21 @@ static void tcp_collapse_ofo_queue(struct sock *sk)
        head = skb;
 
        for (;;) {
-               skb = skb->next;
+               struct sk_buff *next = NULL;
+
+               if (!skb_queue_is_last(&tp->out_of_order_queue, skb))
+                       next = skb_queue_next(&tp->out_of_order_queue, skb);
+               skb = next;
 
                /* Segment is terminated when we see gap or when
                 * we are at the end of all the queue. */
-               if (skb == (struct sk_buff *)&tp->out_of_order_queue ||
+               if (!skb ||
                    after(TCP_SKB_CB(skb)->seq, end) ||
                    before(TCP_SKB_CB(skb)->end_seq, start)) {
                        tcp_collapse(sk, &tp->out_of_order_queue,
                                     head, skb, start, end);
                        head = skb;
-                       if (skb == (struct sk_buff *)&tp->out_of_order_queue)
+                       if (!skb)
                                break;
                        /* Start new segment */
                        start = TCP_SKB_CB(skb)->seq;
@@ -4681,10 +4728,11 @@ static int tcp_prune_queue(struct sock *sk)
                tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
 
        tcp_collapse_ofo_queue(sk);
-       tcp_collapse(sk, &sk->sk_receive_queue,
-                    sk->sk_receive_queue.next,
-                    (struct sk_buff *)&sk->sk_receive_queue,
-                    tp->copied_seq, tp->rcv_nxt);
+       if (!skb_queue_empty(&sk->sk_receive_queue))
+               tcp_collapse(sk, &sk->sk_receive_queue,
+                            skb_peek(&sk->sk_receive_queue),
+                            NULL,
+                            tp->copied_seq, tp->rcv_nxt);
        sk_mem_reclaim(sk);
 
        if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf)