net/ipv6: don't return positive numbers when nothing was dumped

net/ipv6: don't return positive numbers when nothing was dumped

[ Upstream commit 1518039f6b5ac794313c24c76f85cead0cd60f6c ]

in6_dump_addrs() returns a positive 1 if there was nothing to dump.
This return value can not be passed as return from inet6_dump_addr()
as is, because it will confuse rtnetlink, resulting in NLMSG_DONE
never getting set:

$ ip addr list dev lo
EOF on netlink
Dump terminated

v2: flip condition to avoid a new goto (DaveA)

Fixes: 7c1e8a3817c5 ("netlink: fixup regression in RTM_GETADDR")
Reported-by: Brendan Galloway <brendan.galloway@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>