Commit 121fefc6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipmr: do not acquire mrt_lock in __pim_rcv() 



rcu_read_lock() protection is more than enough.

vif_dev_read() supports either mrt_lock or rcu_read_lock().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 64667988

net/ipv4/ipmr.c

+5 −5
Original line number Diff line number Diff line
@@ -582,6 +582,7 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb, 
{

	struct net_device *reg_dev = NULL;

	struct iphdr *encap;

	int vif_num;



	encap = (struct iphdr *)(skb_transport_header(skb) + pimlen);

	/* Check that:
@@ -594,11 +595,10 @@ static int __pim_rcv(struct mr_table *mrt, struct sk_buff *skb, 
	    ntohs(encap->tot_len) + pimlen > skb->len)

		return 1;



	read_lock(&mrt_lock);

	if (mrt->mroute_reg_vif_num >= 0)

		reg_dev = vif_dev_read(&mrt->vif_table[mrt->mroute_reg_vif_num]);

	read_unlock(&mrt_lock);



	/* Pairs with WRITE_ONCE() in vif_add()/vid_delete() */

	vif_num = READ_ONCE(mrt->mroute_reg_vif_num);

	if (vif_num >= 0)

		reg_dev = vif_dev_read(&mrt->vif_table[vif_num]);

	if (!reg_dev)

		return 1;