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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-09 03:03:29 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-04-13 12:41:33 +0400 |
| commit | b6c6712a42ca3f9fa7f4a3d7c40e3a9dd1fd9e03 (patch) | |
| tree | 42032b4978874e8ffcf6c851d13324b8c8c7c113 /include/net/dst.h | |
| parent | 7a161ea92471087a1579239d7a58dd06eaa5601c (diff) | |
| download | linux-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.h | 15 |
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); |