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decnet: use __dev_get_by_index instead of dev_get_by_index to find interface 

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>
This commit is contained in:
Ying Xue 2014-01-15 10:23:40 +08:00 committed by David S. Miller
parent d9ac62be57
commit d4c5fba2f6
1 changed files with 2 additions and 8 deletions
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10
net/decnet/dn_route.c
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@ -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;