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net: TCP early demux cleanup

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early_demux() handlers should be called in RCU context, and as we
use skb_dst_set_noref(skb, dst), caller must not exit from RCU context
before dst use (skb_dst(skb)) or release (skb_drop(dst))

Therefore, rcu_read_lock()/rcu_read_unlock() pairs around
->early_demux() are confusing and not needed :

Protocol handlers are already in an RCU read lock section.
(__netif_receive_skb() does the rcu_read_lock() )

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-07-29 21:06:13 +00:00 committed by David S. Miller
parent 8bbb181308
commit cca32e4bf9
2 changed files with 0 additions and 4 deletions
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2
net/ipv4/ip_input.c
View File

@ -325,14 +325,12 @@ static int ip_rcv_finish(struct sk_buff *skb)
const struct net_protocol *ipprot;
int protocol = iph->protocol;
rcu_read_lock();
ipprot = rcu_dereference(inet_protos[protocol]);
if (ipprot && ipprot->early_demux) {
ipprot->early_demux(skb);
/* must reload iph, skb->head might have changed */
iph = ip_hdr(skb);
}
rcu_read_unlock();
}
/*

2
net/ipv6/ip6_input.c
View File

@ -52,11 +52,9 @@ int ip6_rcv_finish(struct sk_buff *skb)
if (sysctl_ip_early_demux && !skb_dst(skb)) {
const struct inet6_protocol *ipprot;
rcu_read_lock();
ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
if (ipprot && ipprot->early_demux)
ipprot->early_demux(skb);
rcu_read_unlock();
}
if (!skb_dst(skb))
ip6_route_input(skb);