Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/linville...

[mv-sheeva.git] / net / ipv4 / ip_gre.c

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index a1b5d5e030645b945a9b45e3793098701bf9a642..fbe2c473a06a05ca82b0f0d2fff935924aa114e5 100644 (file)
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -64,13 +64,13 @@
    We cannot track such dead loops during route installation,
    it is infeasible task. The most general solutions would be
    to keep skb->encapsulation counter (sort of local ttl),
-   and silently drop packet when it expires. It is the best
+   and silently drop packet when it expires. It is a good
    solution, but it supposes maintaing new variable in ALL
    skb, even if no tunneling is used.
 
-   Current solution: HARD_TX_LOCK lock breaks dead loops.
-
-
+   Current solution: xmit_recursion breaks dead loops. This is a percpu
+   counter, since when we enter the first ndo_xmit(), cpu migration is
+   forbidden. We force an exit if this counter reaches RECURSION_LIMIT
 
    2. Networking dead loops would not kill routers, but would really
    kill network. IP hop limit plays role of "t->recursion" in this case,
@@ -1557,6 +1557,10 @@ static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nla
        if (!tb[IFLA_MTU])
                dev->mtu = mtu;
 
+       /* Can use a lockless transmit, unless we generate output sequences */
+       if (!(nt->parms.o_flags & GRE_SEQ))
+               dev->features |= NETIF_F_LLTX;
+
        err = register_netdevice(dev);
        if (err)
                goto out;