net sched: fix race in mirred device removal

This fixes hang when target device of mirred packet classifier
action is removed.

If a mirror or redirection action is configured to cause packets
to go to another device, the classifier holds a ref count, but was assuming
the adminstrator cleaned up all redirections before removing. The fix
is to add a notifier and cleanup during unregister.

The new list is implicitly protected by RTNL mutex because
it is held during filter add/delete as well as notifier.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/net/tc_act/tc_mirred.h b/include/net/tc_act/tc_mirred.h
index ceac661cdfd5..cfe2943690ff 100644
--- a/include/net/tc_act/tc_mirred.h
+++ b/include/net/tc_act/tc_mirred.h
@@ -9,6 +9,7 @@ struct tcf_mirred {
         int                     tcfm_ifindex;
         int                     tcfm_ok_push;
         struct net_device       *tcfm_dev;
+        struct list_head        tcfm_list;
 };
 #define to_mirred(pc) \
         container_of(pc, struct tcf_mirred, common)