This patch adds ability to filter sockets based on cgroup v2 ID.
Such filter is helpful in ss utility for filtering sockets by
cgroup pathname.
Signed-off-by: NDmitry Yakunin <zeil@yandex-team.ru>
Reviewed-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>