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Commit 69df9d59 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ip_frag: dont touch device refcount 



When sending fragmentation expiration ICMP V4/V6 messages,
we can avoid touching device refcount, thanks to RCU

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bd27a875

net/ipv4/ip_fragment.c

+4 −3
Original line number Diff line number Diff line
@@ -206,10 +206,11 @@ static void ip_expire(unsigned long arg) 
		struct sk_buff *head = qp->q.fragments;



		/* Send an ICMP "Fragment Reassembly Timeout" message. */

		if ((head->dev = dev_get_by_index(net, qp->iif)) != NULL) {

		rcu_read_lock();

		head->dev = dev_get_by_index_rcu(net, qp->iif);

		if (head->dev)

			icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);

			dev_put(head->dev);

		}

		rcu_read_unlock();

	}

out:

	spin_unlock(&qp->q.lock);

net/ipv6/reassembly.c

+6 −7
Original line number Diff line number Diff line
@@ -208,18 +208,17 @@ static void ip6_frag_expire(unsigned long data) 
	fq_kill(fq);



	net = container_of(fq->q.net, struct net, ipv6.frags);

	dev = dev_get_by_index(net, fq->iif);

	rcu_read_lock();

	dev = dev_get_by_index_rcu(net, fq->iif);

	if (!dev)

		goto out;

		goto out_rcu_unlock;



	rcu_read_lock();

	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMTIMEOUT);

	IP6_INC_STATS_BH(net, __in6_dev_get(dev), IPSTATS_MIB_REASMFAILS);

	rcu_read_unlock();



	/* Don't send error if the first segment did not arrive. */

	if (!(fq->q.last_in & INET_FRAG_FIRST_IN) || !fq->q.fragments)

		goto out;

		goto out_rcu_unlock;



	/*

	   But use as source device on which LAST ARRIVED
@@ -228,9 +227,9 @@ static void ip6_frag_expire(unsigned long data) 
	 */

	fq->q.fragments->dev = dev;

	icmpv6_send(fq->q.fragments, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0, dev);

out_rcu_unlock:

	rcu_read_unlock();

out:

	if (dev)

		dev_put(dev);

	spin_unlock(&fq->q.lock);

	fq_put(fq);

}