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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/dst.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/dst.h')
-rw-r--r--include/net/dst.h15
1 files changed, 0 insertions, 15 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
index ce078cda6b74..aac5a5fcfda9 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -225,21 +225,6 @@ static inline void dst_confirm(struct dst_entry *dst)
neigh_confirm(dst->neighbour);
}
-static inline void dst_negative_advice(struct dst_entry **dst_p,
- struct sock *sk)
-{
- struct dst_entry * dst = *dst_p;
- if (dst && dst->ops->negative_advice) {
- *dst_p = dst->ops->negative_advice(dst);
-
- if (dst != *dst_p) {
- extern void sk_reset_txq(struct sock *sk);
-
- sk_reset_txq(sk);
- }
- }
-}
-
static inline void dst_link_failure(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);