[NETNS][IPV6] ip6_fib - add net to gc timer parameter

The fib tables are now relative to the network namespace. When the
garbage collector timer expires, we must have a network namespace
parameter in order to retrieve the tables. For now this is the
init_net, but we should be able to have a timer per namespace and use
the timer callback parameter to pass the network namespace from the
expired timer.

The timer callback, fib6_run_gc, is actually used to be called
synchronously by some functions and asynchronously when the timer
expires.

When the timer expires, the delay specified for fib6_run_gc parameter
is always zero. So, I changed fib6_run_gc to not be a timer callback
but a function called by the timer callback and I added a timer
callback where its work is just to retrieve from the data arg of the
timer the network namespace and call fib6_run_gc with zero expiring
time and the network namespace parameters. That makes the code cleaner
for the fib6_run_gc callers.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index eb32295..f1c9512 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1598,6 +1598,7 @@
 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
 	struct net_device *dev = ptr;
+	struct net *net = dev->nd_net;
 
 	if (dev->nd_net != &init_net)
 		return NOTIFY_DONE;
@@ -1605,11 +1606,11 @@
 	switch (event) {
 	case NETDEV_CHANGEADDR:
 		neigh_changeaddr(&nd_tbl, dev);
-		fib6_run_gc(~0UL);
+		fib6_run_gc(~0UL, net);
 		break;
 	case NETDEV_DOWN:
 		neigh_ifdown(&nd_tbl, dev);
-		fib6_run_gc(~0UL);
+		fib6_run_gc(~0UL, net);
 		break;
 	default:
 		break;