From 54764bb647b2e847c512acf8d443df965da35000 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 31 Jul 2012 01:08:23 +0000 Subject: ipv4: Restore old dst_free() behavior. commit 404e0a8b6a55 (net: ipv4: fix RCU races on dst refcounts) tried to solve a race but added a problem at device/fib dismantle time : We really want to call dst_free() as soon as possible, even if sockets still have dst in their cache. dst_release() calls in free_fib_info_rcu() are not welcomed. Root of the problem was that now we also cache output routes (in nh_rth_output), we must use call_rcu() instead of call_rcu_bh() in rt_free(), because output route lookups are done in process context. Based on feedback and initial patch from David Miller (adding another call_rcu_bh() call in fib, but it appears it was not the right fix) I left the inet_sk_rx_dst_set() helper and added __rcu attributes to nh_rth_output and nh_rth_input to better document what is going on in this code. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inet_sock.h | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) (limited to 'include/net/inet_sock.h') diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index e3fd34c83ac9..83b567fe1941 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -253,13 +253,9 @@ static inline void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb { struct dst_entry *dst = skb_dst(skb); - if (atomic_inc_not_zero(&dst->__refcnt)) { - if (!(dst->flags & DST_RCU_FREE)) - dst->flags |= DST_RCU_FREE; - - sk->sk_rx_dst = dst; - inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; - } + dst_hold(dst); + sk->sk_rx_dst = dst; + inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; } #endif /* _INET_SOCK_H */ -- cgit v1.2.1