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Message-Id: <20090529.014023.128822939.davem@davemloft.net>
Date: Fri, 29 May 2009 01:40:23 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: netdev@...r.kernel.org
CC: linux-wireless@...r.kernel.org
Subject: [PATCH 8/10]: tcp: Use SKB queue and list helpers instead of doing
it by-hand.
Signed-off-by: David S. Miller <davem@...emloft.net>
---
net/ipv4/tcp.c | 17 +++----
net/ipv4/tcp_input.c | 118 +++++++++++++++++++++++++++++++++++---------------
2 files changed, 90 insertions(+), 45 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0fb8b44..17b89c5 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -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. */
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index eeb8a92..ba34a23 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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)
--
1.6.3
--
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