[IPV6]: Address autoconfiguration does not work after device down/up cycle
[IPV6]: Address autoconfiguration does not work after device down/up cycle

If you set network interface down and up again, the IPv6 address
autoconfiguration does not work. 'ip addr' shows that the link-local
address is in tentative state. We don't even react to periodical router
advertisements.

During NETDEV_DOWN we clear IF_READY, and we don't set it back in
NETDEV_UP. While starting to perform DAD on the link-local address, we
notice that the device is not in IF_READY, and we abort autoconfiguration
process (which would eventually send router solicitations).

Acked-by: Juha-Matti Tapio <fddc8e854182e87a8b33fa8e84373c01c227b16d@verkkotelakka.net>
Acked-by: YOSHIFUJI Hideaki <948b80da4254122ea1e8973dd9930d46b7654cf3@linux-ipv6.org>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs