Commit db9eb7c8 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ip6mr: do not acquire mrt_lock before calling ip6mr_cache_unresolved 



rcu_read_lock() protection is good enough.

ip6mr_cache_unresolved() uses a dedicated spinlock (mfc_unres_lock)

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 638cf4a2

net/ipv6/ip6mr.c

+6 −6
Original line number Original line Diff line number Diff line
@@ -730,7 +730,7 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify, 
			if (VIF_EXISTS(mrt, tmp))

			if (VIF_EXISTS(mrt, tmp))

				break;

				break;

		}

		}

		mrt->maxvif = tmp + 1;

		WRITE_ONCE(mrt->maxvif, tmp + 1);

	}

	}





	write_unlock_bh(&mrt_lock);

	write_unlock_bh(&mrt_lock);
@@ -927,7 +927,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt, 
		WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);

		WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);

#endif

#endif

	if (vifi + 1 > mrt->maxvif)

	if (vifi + 1 > mrt->maxvif)

		mrt->maxvif = vifi + 1;

		WRITE_ONCE(mrt->maxvif, vifi + 1);

	write_unlock_bh(&mrt_lock);

	write_unlock_bh(&mrt_lock);

	call_ip6mr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD,

	call_ip6mr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD,

				       v, dev, vifi, mrt->id);

				       v, dev, vifi, mrt->id);
@@ -2099,11 +2099,13 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt, 
	return 0;

	return 0;

}

}





/* Called with mrt_lock or rcu_read_lock() */

static int ip6mr_find_vif(struct mr_table *mrt, struct net_device *dev)

static int ip6mr_find_vif(struct mr_table *mrt, struct net_device *dev)

{

{

	int ct;

	int ct;





	for (ct = mrt->maxvif - 1; ct >= 0; ct--) {

	/* Pairs with WRITE_ONCE() in mif6_delete()/mif6_add() */

	for (ct = READ_ONCE(mrt->maxvif) - 1; ct >= 0; ct--) {

		if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)

		if (rcu_access_pointer(mrt->vif_table[ct].dev) == dev)

			break;

			break;

	}

	}
@@ -2249,7 +2251,6 @@ int ip6_mr_input(struct sk_buff *skb) 
		return err;

		return err;

	}

	}





	read_lock(&mrt_lock);

	cache = ip6mr_cache_find(mrt,

	cache = ip6mr_cache_find(mrt,

				 &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr);

				 &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr);

	if (!cache) {

	if (!cache) {
@@ -2270,15 +2271,14 @@ int ip6_mr_input(struct sk_buff *skb) 
		vif = ip6mr_find_vif(mrt, dev);

		vif = ip6mr_find_vif(mrt, dev);

		if (vif >= 0) {

		if (vif >= 0) {

			int err = ip6mr_cache_unresolved(mrt, vif, skb, dev);

			int err = ip6mr_cache_unresolved(mrt, vif, skb, dev);

			read_unlock(&mrt_lock);





			return err;

			return err;

		}

		}

		read_unlock(&mrt_lock);

		kfree_skb(skb);

		kfree_skb(skb);

		return -ENODEV;

		return -ENODEV;

	}

	}





	read_lock(&mrt_lock);

	ip6_mr_forward(net, mrt, dev, skb, cache);

	ip6_mr_forward(net, mrt, dev, skb, cache);





	read_unlock(&mrt_lock);

	read_unlock(&mrt_lock);