decnet: use __dev_get_by_index instead of dev_get_by_index to find interface (d4c5fba2) · Commits · 戴 / test

The following call chain we can identify that dn_cache_getroute() is protected under rtnl_lock. So if we use __dev_get_by_index() instead of dev_get_by_index() to find interface handlers in it, this would help us avoid to change interface reference counter. rtnetlink_rcv() rtnl_lock() netlink_rcv_skb() dn_cache_getroute() rtnl_unlock() Signed-off-by:

Ying Xue <ying.xue@windriver.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/decnet/dn_route.c

+2 −8

Original line number	Diff line number	Diff line
		@@ -1666,12 +1666,8 @@ static int dn_cache_getroute(struct sk_buff in_skb, struct nlmsghdr nlh)

		if (fld.flowidn_iif) {
		struct net_device *dev;
		if ((dev = dev_get_by_index(&init_net, fld.flowidn_iif)) == NULL) {
		kfree_skb(skb);
		return -ENODEV;
		}
		if (!dev->dn_ptr) {
		dev_put(dev);
		dev = __dev_get_by_index(&init_net, fld.flowidn_iif);
		if (!dev \|\| !dev->dn_ptr) {
		kfree_skb(skb);
		return -ENODEV;
		}
		@@ -1693,8 +1689,6 @@ static int dn_cache_getroute(struct sk_buff in_skb, struct nlmsghdr nlh)
		err = dn_route_output_key((struct dst_entry **)&rt, &fld, 0);
		}

		if (skb->dev)
		dev_put(skb->dev);
		skb->dev = NULL;
		if (err)
		goto out_free;

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