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authorEric Dumazet <eric.dumazet@gmail.com>2010-04-08 19:03:29 -0400
committerDavid S. Miller <davem@davemloft.net>2010-04-13 04:41:33 -0400
commitb6c6712a42ca3f9fa7f4a3d7c40e3a9dd1fd9e03 (patch)
tree42032b4978874e8ffcf6c851d13324b8c8c7c113 /net/ipv4/af_inet.c
parent7a161ea92471087a1579239d7a58dd06eaa5601c (diff)
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 'net/ipv4/af_inet.c')
-rw-r--r--net/ipv4/af_inet.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index a0beb32beaa3..193dcd6ed64f 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -154,7 +154,7 @@ void inet_sock_destruct(struct sock *sk)
154 WARN_ON(sk->sk_forward_alloc); 154 WARN_ON(sk->sk_forward_alloc);
155 155
156 kfree(inet->opt); 156 kfree(inet->opt);
157 dst_release(sk->sk_dst_cache); 157 dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
158 sk_refcnt_debug_dec(sk); 158 sk_refcnt_debug_dec(sk);
159} 159}
160EXPORT_SYMBOL(inet_sock_destruct); 160EXPORT_SYMBOL(inet_sock_destruct);