igmp: call ip_mc_clear_src() only when we have no users of ip_mc_list
authorVeaceslav Falico <vfalico@redhat.com>
Mon, 23 May 2011 23:15:05 +0000 (23:15 +0000)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 3 Jun 2011 00:31:55 +0000 (09:31 +0900)
commit40093a2a3e53af2f1a0754fe40b7513ebf6e0c8f
treee32610a20a7646e8be075737d8df540630260e1e
parenta0e3d9a50be5f6cffbc4fbc9e44105c5def26cf0
igmp: call ip_mc_clear_src() only when we have no users of ip_mc_list

[ Upstream commit 24cf3af3fed5edcf90bc2a0ed181e6ce1513d2dc ]

In igmp_group_dropped() we call ip_mc_clear_src(), which resets the number
of source filters per mulitcast. However, igmp_group_dropped() is also
called on NETDEV_DOWN, NETDEV_PRE_TYPE_CHANGE and NETDEV_UNREGISTER, which
means that the group might get added back on NETDEV_UP, NETDEV_REGISTER and
NETDEV_POST_TYPE_CHANGE respectively, leaving us with broken source
filters.

To fix that, we must clear the source filters only when there are no users
in the ip_mc_list, i.e. in ip_mc_dec_group() and on device destroy.

Acked-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
net/ipv4/igmp.c