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Commit 519fbd87 authored by YOSHIFUJI Hideaki's avatar YOSHIFUJI Hideaki Committed by David S. Miller
Browse files

[IPV6]: ROUTE: Clean-up cow'ing in ip6_route_{intput,output}(). 



Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e40cf353

net/ipv6/route.c

+60 −53
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ 
#define RT6_TRACE(x...) do { ; } while (0)

#endif



#define CLONE_OFFLINK_ROUTE 0



static int ip6_rt_max_size = 4096;

static int ip6_rt_gc_min_interval = HZ / 2;
@@ -465,9 +466,10 @@ if (rt == &ip6_null_entry && strict) { \ 
void ip6_route_input(struct sk_buff *skb)

{

	struct fib6_node *fn;

	struct rt6_info *rt;

	struct rt6_info *rt, *nrt;

	int strict;

	int attempts = 3;

	int err;



	strict = ipv6_addr_type(&skb->nh.ipv6h->daddr) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL);
@@ -492,20 +494,22 @@ void ip6_route_input(struct sk_buff *skb) 
	dst_hold(&rt->u.dst);

	read_unlock_bh(&rt6_lock);



	if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP)) {

		struct rt6_info *nrt;

		int err;



		nrt = rt6_alloc_cow(rt, &skb->nh.ipv6h->daddr,

				    &skb->nh.ipv6h->saddr);

	if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))

		nrt = rt6_alloc_cow(rt, &skb->nh.ipv6h->daddr, &skb->nh.ipv6h->saddr);

	else {

#if CLONE_OFFLINK_ROUTE

		nrt = rt6_alloc_clone(rt, &skb->nh.ipv6h->daddr);

#else

		goto out2;

#endif

	}



	dst_release(&rt->u.dst);

	rt = nrt ? : &ip6_null_entry;



	dst_hold(&rt->u.dst);

	if (nrt) {

			err = ip6_ins_rt(nrt, NULL, NULL,

					 &NETLINK_CB(skb));

		err = ip6_ins_rt(nrt, NULL, NULL, &NETLINK_CB(skb));

		if (!err)

			goto out2;

	}
@@ -513,30 +517,30 @@ void ip6_route_input(struct sk_buff *skb) 
	if (--attempts <= 0)

		goto out2;



		/* Race condition! In the gap, when rt6_lock was

		   released someone could insert this route.  Relookup.

	/*

	 * Race condition! In the gap, when rt6_lock was

	 * released someone could insert this route.  Relookup.

	 */

	dst_release(&rt->u.dst);

	goto relookup;

	}



out:

	dst_hold(&rt->u.dst);

	read_unlock_bh(&rt6_lock);

out2:

	rt->u.dst.lastuse = jiffies;

	rt->u.dst.__use++;

	skb->dst = (struct dst_entry *) rt;

	return;

out:

	dst_hold(&rt->u.dst);

	read_unlock_bh(&rt6_lock);

	goto out2;

}



struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl)

{

	struct fib6_node *fn;

	struct rt6_info *rt;

	struct rt6_info *rt, *nrt;

	int strict;

	int attempts = 3;

	int err;



	strict = ipv6_addr_type(&fl->fl6_dst) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL);
@@ -564,11 +568,15 @@ struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl) 
	dst_hold(&rt->u.dst);

	read_unlock_bh(&rt6_lock);



	if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP)) {

		struct rt6_info *nrt;

		int err;



	if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))

		nrt = rt6_alloc_cow(rt, &fl->fl6_dst, &fl->fl6_src);

	else {

#if CLONE_OFFLINK_ROUTE

		nrt = rt6_alloc_clone(rt, &fl->fl6_dst);

#else

		goto out2;

#endif

	}



	dst_release(&rt->u.dst);

	rt = nrt ? : &ip6_null_entry;
@@ -583,21 +591,20 @@ struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl) 
	if (--attempts <= 0)

		goto out2;



		/* Race condition! In the gap, when rt6_lock was

		   released someone could insert this route.  Relookup.

	/*

	 * Race condition! In the gap, when rt6_lock was

	 * released someone could insert this route.  Relookup.

	 */

	dst_release(&rt->u.dst);

	goto relookup;

	}



out:

	dst_hold(&rt->u.dst);

	read_unlock_bh(&rt6_lock);

out2:

	rt->u.dst.lastuse = jiffies;

	rt->u.dst.__use++;

	return &rt->u.dst;

out:

	dst_hold(&rt->u.dst);

	read_unlock_bh(&rt6_lock);

	goto out2;

}