We only need to do the synchronize_net dance once for both, ipv4 and
ipv6 sockets, thus removing one synchronize_net in case both sockets get
dismantled.
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>