net: ipv6: lower ndisc notifier priority below addrconf

ndisc_notify is used to send unsolicited neighbor advertisements
(e.g., on a link up). Currently, the ndisc notifier is run before the
addrconf notifer which means NA's are not sent for link-local addresses
which are added by the addrconf notifier.

Fix by lowering the priority of the ndisc notifier. Setting the priority
to ADDRCONF_NOTIFY_PRIORITY - 5 means it runs after addrconf and before
the route notifier which is ADDRCONF_NOTIFY_PRIORITY - 10.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ndisc.c

@@ -1779,6 +1779,7 @@ static int ndisc_netdev_event(struct notifier_block *this, unsigned long event,
 
 static struct notifier_block ndisc_netdev_notifier = {
 	.notifier_call = ndisc_netdev_event,
+	.priority = ADDRCONF_NOTIFY_PRIORITY - 5,
 };
 
 #ifdef CONFIG_SYSCTL