netdev - [PATCH net-next] tcp: connect() from bound sockets can be faster

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Date:	Wed, 27 May 2015 10:46:02 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Crestez Dan Leonard <cdleonard@...il.com>,
	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: [PATCH net-next] tcp: connect() from bound sockets can be faster

From: Eric Dumazet <edumazet@...gle.com>

__inet_hash_connect() does not use its third argument (port_offset)
if socket was already bound to a source port.

No need to perform useless but expensive md5 computations.

Reported-by: Crestez Dan Leonard <cdleonard@...il.com>
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/ipv4/inet_hashtables.c  |    9 +++++++--
 net/ipv6/inet6_hashtables.c |    8 ++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 185efef0f1251ba9d45fabb3ed51777a8be097a6..e36942f0725d2e2d15f8d248b19a34c3487528ef 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -394,9 +394,10 @@ not_unique:
 	return -EADDRNOTAVAIL;
 }
 
-static inline u32 inet_sk_port_offset(const struct sock *sk)
+static u32 inet_sk_port_offset(const struct sock *sk)
 {
 	const struct inet_sock *inet = inet_sk(sk);
+
 	return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
 					  inet->inet_daddr,
 					  inet->inet_dport);
@@ -594,7 +595,11 @@ out:
 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 		      struct sock *sk)
 {
-	return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
+	u32 port_offset = 0;
+
+	if (!inet_sk(sk)->inet_num)
+		port_offset = inet_sk_port_offset(sk);
+	return __inet_hash_connect(death_row, sk, port_offset,
 				   __inet_check_established);
 }
 EXPORT_SYMBOL_GPL(inet_hash_connect);
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 871641bc1ed4eb5b8f5f554c9efb75f2419fe5b6..b4fd96de97e61627003eff220e10bdd05a899e28 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -257,7 +257,7 @@ not_unique:
 	return -EADDRNOTAVAIL;
 }
 
-static inline u32 inet6_sk_port_offset(const struct sock *sk)
+static u32 inet6_sk_port_offset(const struct sock *sk)
 {
 	const struct inet_sock *inet = inet_sk(sk);
 
@@ -269,7 +269,11 @@ static inline u32 inet6_sk_port_offset(const struct sock *sk)
 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 		       struct sock *sk)
 {
-	return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk),
+	u32 port_offset = 0;
+
+	if (!inet_sk(sk)->inet_num)
+		port_offset = inet6_sk_port_offset(sk);
+	return __inet_hash_connect(death_row, sk, port_offset,
 				   __inet6_check_established);
 }
 EXPORT_SYMBOL_GPL(inet6_hash_connect);


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