netdev - [PATCH 1/2] tcp: refactor tcp_retransmit

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Date:	Fri, 16 Dec 2011 17:16:26 -0500
From:	Satoru Moriya <satoru.moriya@....com>
To:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:	"nhorman@...driver.com" <nhorman@...driver.com>,
	"davem@...emloft.net" <davem@...emloft.net>,
	"tgraf@...radead.org" <tgraf@...radead.org>,
	Seiji Aguchi <seiji.aguchi@....com>,
	"dle-develop@...ts.sourceforge.net" 
	<dle-develop@...ts.sourceforge.net>
Subject: [PATCH 1/2] tcp: refactor tcp_retransmit_skb() for a single return
 point

This is just a cleanup patch for making easy to hook return value
with a tracepoint.

Signed-off-by: Satoru Moriya <satoru.moriya@....com>
---
 net/ipv4/tcp_output.c |   31 +++++++++++++++++++++----------
 1 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 63170e2..13d3a79 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2089,18 +2089,24 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	 * copying overhead: fragmentation, tunneling, mangling etc.
 	 */
 	if (atomic_read(&sk->sk_wmem_alloc) >
-	    min(sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf))
-		return -EAGAIN;
+	    min(sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf)) {
+		err = -EAGAIN;
+		goto out;
+	}
 
 	if (before(TCP_SKB_CB(skb)->seq, tp->snd_una)) {
 		if (before(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
 			BUG();
-		if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq))
-			return -ENOMEM;
+		if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq)) {
+			err = -ENOMEM;
+			goto out;
+		}
 	}
 
-	if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk))
-		return -EHOSTUNREACH; /* Routing failure or similar. */
+	if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk)) {
+		err = -EHOSTUNREACH; /* Routing failure or similar. */
+		goto out;
+	}
 
 	cur_mss = tcp_current_mss(sk);
 
@@ -2110,12 +2116,16 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	 * our retransmit serves as a zero window probe.
 	 */
 	if (!before(TCP_SKB_CB(skb)->seq, tcp_wnd_end(tp)) &&
-	    TCP_SKB_CB(skb)->seq != tp->snd_una)
-		return -EAGAIN;
+	    TCP_SKB_CB(skb)->seq != tp->snd_una) {
+		err = -EAGAIN;
+		goto out;
+	}
 
 	if (skb->len > cur_mss) {
-		if (tcp_fragment(sk, skb, cur_mss, cur_mss))
-			return -ENOMEM; /* We'll try again later. */
+		if (tcp_fragment(sk, skb, cur_mss, cur_mss)) {
+			err = -ENOMEM; /* We'll try again later. */
+			goto out;
+		}
 	} else {
 		int oldpcount = tcp_skb_pcount(skb);
 
@@ -2177,6 +2187,7 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 		 */
 		TCP_SKB_CB(skb)->ack_seq = tp->snd_nxt;
 	}
+out:
 	return err;
 }
 
-- 
1.7.6.4
--
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