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authorEric Dumazet <eric.dumazet@gmail.com>2010-04-09 03:03:29 +0400
committerDavid S. Miller <davem@davemloft.net>2010-04-13 12:41:33 +0400
commitb6c6712a42ca3f9fa7f4a3d7c40e3a9dd1fd9e03 (patch)
tree42032b4978874e8ffcf6c851d13324b8c8c7c113 /include/net/ip6_route.h
parent7a161ea92471087a1579239d7a58dd06eaa5601c (diff)
downloadlinux-b6c6712a42ca3f9fa7f4a3d7c40e3a9dd1fd9e03.tar.xz
net: sk_dst_cache RCUification
With latest CONFIG_PROVE_RCU stuff, I felt more comfortable to make this work. sk->sk_dst_cache is currently protected by a rwlock (sk_dst_lock) This rwlock is readlocked for a very small amount of time, and dst entries are already freed after RCU grace period. This calls for RCU again :) This patch converts sk_dst_lock to a spinlock, and use RCU for readers. __sk_dst_get() is supposed to be called with rcu_read_lock() or if socket locked by user, so use appropriate rcu_dereference_check() condition (rcu_read_lock_held() || sock_owned_by_user(sk)) This patch avoids two atomic ops per tx packet on UDP connected sockets, for example, and permits sk_dst_lock to be much less dirtied. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/ip6_route.h')
-rw-r--r--include/net/ip6_route.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 68f67836e146..278312c95f96 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -152,9 +152,9 @@ static inline void __ip6_dst_store(struct sock *sk, struct dst_entry *dst,
static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
struct in6_addr *daddr, struct in6_addr *saddr)
{
- write_lock(&sk->sk_dst_lock);
+ spin_lock(&sk->sk_dst_lock);
__ip6_dst_store(sk, dst, daddr, saddr);
- write_unlock(&sk->sk_dst_lock);
+ spin_unlock(&sk->sk_dst_lock);
}
static inline int ipv6_unicast_destination(struct sk_buff *skb)