From 4edf547b4d0f886acf5aa5a0c8f8edbaff280830 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes@sipsolutions.net>
Date: Wed, 15 Jul 2009 06:16:34 +0000
Subject: [PATCH] net: explain netns notifiers a little better
Eric explained this to me -- and afterwards the comment
made sense, but not before. Add the the critical point
about interfaces having to be gone from the netns before
subsys notifiers are called.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/net_namespace.h | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 5c5136fceea8..a1202841aadd 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -239,13 +239,15 @@ struct pernet_operations {
* needs per network namespace operations use device pernet operations,
* otherwise use pernet subsys operations.
*
- * This is critically important. Most of the network code cleanup
- * runs with the assumption that dev_remove_pack has been called so no
- * new packets will arrive during and after the cleanup functions have
- * been called. dev_remove_pack is not per namespace so instead the
- * guarantee of no more packets arriving in a network namespace is
- * provided by ensuring that all network devices and all sockets have
- * left the network namespace before the cleanup methods are called.
+ * Network interfaces need to be removed from a dying netns _before_
+ * subsys notifiers can be called, as most of the network code cleanup
+ * (which is done from subsys notifiers) runs with the assumption that
+ * dev_remove_pack has been called so no new packets will arrive during
+ * and after the cleanup functions have been called. dev_remove_pack
+ * is not per namespace so instead the guarantee of no more packets
+ * arriving in a network namespace is provided by ensuring that all
+ * network devices and all sockets have left the network namespace
+ * before the cleanup methods are called.
*
* For the longest time the ipv4 icmp code was registered as a pernet
* device which caused kernel oops, and panics during network
--
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