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Date: Sun, 18 Mar 2012 14:06:44 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: Neal Cardwell <ncardwell@...gle.com>
Cc: David Miller <davem@...emloft.net>,
netdev <netdev@...r.kernel.org>,
Tom Herbert <therbert@...gle.com>,
Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>,
"H.K. Jerry Chu" <hkchu@...gle.com>,
Yuchung Cheng <ycheng@...gle.com>
Subject: [PATCH v2 net-next 1/2] tcp: introduce tcp_data_queue_ofo
Split tcp_data_queue() in two parts for better readability.
tcp_data_queue_ofo() is responsible for queueing incoming skb into out
of order queue.
Change code layout so that the skb_set_owner_r() is performed only if
skb is not dropped.
This is a preliminary patch before "reduce out_of_order memory use"
following patch.
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
Cc: Neal Cardwell <ncardwell@...gle.com>
Cc: Yuchung Cheng <ycheng@...gle.com>
Cc: H.K. Jerry Chu <hkchu@...gle.com>
Cc: Tom Herbert <therbert@...gle.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>
---
net/ipv4/tcp_input.c | 214 ++++++++++++++++++++++-------------------
1 file changed, 115 insertions(+), 99 deletions(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 68d4057..fa7de12 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4446,6 +4446,120 @@ static inline int tcp_try_rmem_schedule(struct sock *sk, unsigned int size)
return 0;
}
+static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct sk_buff *skb1;
+ u32 seq, end_seq;
+
+ TCP_ECN_check_ce(tp, skb);
+
+ if (tcp_try_rmem_schedule(sk, skb->truesize)) {
+ /* TODO: should increment a counter */
+ __kfree_skb(skb);
+ return;
+ }
+
+ /* Disable header prediction. */
+ tp->pred_flags = 0;
+ inet_csk_schedule_ack(sk);
+
+ SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n",
+ tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
+
+ skb1 = skb_peek_tail(&tp->out_of_order_queue);
+ if (!skb1) {
+ /* Initial out of order segment, build 1 SACK. */
+ if (tcp_is_sack(tp)) {
+ tp->rx_opt.num_sacks = 1;
+ tp->selective_acks[0].start_seq = TCP_SKB_CB(skb)->seq;
+ tp->selective_acks[0].end_seq =
+ TCP_SKB_CB(skb)->end_seq;
+ }
+ __skb_queue_head(&tp->out_of_order_queue, skb);
+ goto end;
+ }
+
+ seq = TCP_SKB_CB(skb)->seq;
+ end_seq = TCP_SKB_CB(skb)->end_seq;
+
+ if (seq == TCP_SKB_CB(skb1)->end_seq) {
+ __skb_queue_after(&tp->out_of_order_queue, skb1, skb);
+
+ if (!tp->rx_opt.num_sacks ||
+ tp->selective_acks[0].end_seq != seq)
+ goto add_sack;
+
+ /* Common case: data arrive in order after hole. */
+ tp->selective_acks[0].end_seq = end_seq;
+ goto end;
+ }
+
+ /* Find place to insert this segment. */
+ while (1) {
+ if (!after(TCP_SKB_CB(skb1)->seq, seq))
+ break;
+ 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 && 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);
+ skb = NULL;
+ tcp_dsack_set(sk, seq, end_seq);
+ goto add_sack;
+ }
+ if (after(seq, TCP_SKB_CB(skb1)->seq)) {
+ /* Partial overlap. */
+ tcp_dsack_set(sk, seq,
+ TCP_SKB_CB(skb1)->end_seq);
+ } else {
+ if (skb_queue_is_first(&tp->out_of_order_queue,
+ skb1))
+ skb1 = NULL;
+ else
+ skb1 = skb_queue_prev(
+ &tp->out_of_order_queue,
+ skb1);
+ }
+ }
+ 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 (!skb_queue_is_last(&tp->out_of_order_queue, skb)) {
+ skb1 = skb_queue_next(&tp->out_of_order_queue, skb);
+
+ 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,
+ TCP_SKB_CB(skb1)->end_seq);
+ __kfree_skb(skb1);
+ }
+
+add_sack:
+ if (tcp_is_sack(tp))
+ tcp_sack_new_ofo_skb(sk, seq, end_seq);
+end:
+ if (skb)
+ skb_set_owner_r(skb, sk);
+}
+
+
static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
{
const struct tcphdr *th = tcp_hdr(skb);
@@ -4561,105 +4675,7 @@ drop:
goto queue_and_out;
}
- TCP_ECN_check_ce(tp, skb);
-
- if (tcp_try_rmem_schedule(sk, skb->truesize))
- goto drop;
-
- /* Disable header prediction. */
- tp->pred_flags = 0;
- inet_csk_schedule_ack(sk);
-
- SOCK_DEBUG(sk, "out of order segment: rcv_next %X seq %X - %X\n",
- tp->rcv_nxt, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
-
- skb_set_owner_r(skb, sk);
-
- if (!skb_peek(&tp->out_of_order_queue)) {
- /* Initial out of order segment, build 1 SACK. */
- if (tcp_is_sack(tp)) {
- tp->rx_opt.num_sacks = 1;
- tp->selective_acks[0].start_seq = TCP_SKB_CB(skb)->seq;
- tp->selective_acks[0].end_seq =
- TCP_SKB_CB(skb)->end_seq;
- }
- __skb_queue_head(&tp->out_of_order_queue, skb);
- } else {
- 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;
-
- if (seq == TCP_SKB_CB(skb1)->end_seq) {
- __skb_queue_after(&tp->out_of_order_queue, skb1, skb);
-
- if (!tp->rx_opt.num_sacks ||
- tp->selective_acks[0].end_seq != seq)
- goto add_sack;
-
- /* Common case: data arrive in order after hole. */
- tp->selective_acks[0].end_seq = end_seq;
- return;
- }
-
- /* Find place to insert this segment. */
- while (1) {
- if (!after(TCP_SKB_CB(skb1)->seq, seq))
- break;
- 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 && 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);
- tcp_dsack_set(sk, seq, end_seq);
- goto add_sack;
- }
- if (after(seq, TCP_SKB_CB(skb1)->seq)) {
- /* Partial overlap. */
- tcp_dsack_set(sk, seq,
- TCP_SKB_CB(skb1)->end_seq);
- } else {
- if (skb_queue_is_first(&tp->out_of_order_queue,
- skb1))
- skb1 = NULL;
- else
- skb1 = skb_queue_prev(
- &tp->out_of_order_queue,
- skb1);
- }
- }
- 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 (!skb_queue_is_last(&tp->out_of_order_queue, skb)) {
- skb1 = skb_queue_next(&tp->out_of_order_queue, skb);
-
- 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,
- TCP_SKB_CB(skb1)->end_seq);
- __kfree_skb(skb1);
- }
-
-add_sack:
- if (tcp_is_sack(tp))
- tcp_sack_new_ofo_skb(sk, seq, end_seq);
- }
+ tcp_data_queue_ofo(sk, skb);
}
static struct sk_buff *tcp_collapse_one(struct sock *sk, struct sk_buff *skb,
--
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