From 723b46108f8ee75b61ce703d0c9225e4f537bc46 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Tue, 25 Nov 2008 13:55:15 -0800
Subject: net: udp_unhash() can test if sk is hashed
Impact: Optimization
Like done in inet_unhash(), we can avoid taking a chain lock if
socket is not hashed in udp_unhash()
Triggered by close(socket(AF_INET, SOCK_DGRAM, 0));
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/udp.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
(limited to 'net/ipv4/udp.c')
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 549114472db3..cf5ab0581eba 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -970,16 +970,18 @@ int udp_disconnect(struct sock *sk, int flags)
void udp_lib_unhash(struct sock *sk)
{
- struct udp_table *udptable = sk->sk_prot->h.udp_table;
- unsigned int hash = udp_hashfn(sock_net(sk), sk->sk_hash);
- struct udp_hslot *hslot = &udptable->hash[hash];
+ if (sk_hashed(sk)) {
+ struct udp_table *udptable = sk->sk_prot->h.udp_table;
+ unsigned int hash = udp_hashfn(sock_net(sk), sk->sk_hash);
+ struct udp_hslot *hslot = &udptable->hash[hash];
- spin_lock_bh(&hslot->lock);
- if (sk_nulls_del_node_init_rcu(sk)) {
- inet_sk(sk)->num = 0;
- sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+ spin_lock_bh(&hslot->lock);
+ if (sk_nulls_del_node_init_rcu(sk)) {
+ inet_sk(sk)->num = 0;
+ sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+ }
+ spin_unlock_bh(&hslot->lock);
}
- spin_unlock_bh(&hslot->lock);
}
EXPORT_SYMBOL(udp_lib_unhash);
--
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