From 6d0722a2cec2c23db3b0855ff8bb433175a16b44 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 29 Sep 2010 23:35:10 -0700
Subject: ip_gre: comments change

HARD_TX_LOCK no longer protects tunnels from dead loops,
but xmit_recursion percpu counter.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv4/ip_gre.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 035db6350037..fbe2c473a06a 100644
--- 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,
-- 
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