netprio_cgroup: limit the maximum css->id to USHRT_MAX
netprio builds per-netdev contiguous priomap array which is indexed by
css->id. The array is allocated using kzalloc() effectively limiting
the maximum ID supported to some thousand range. This patch caps the
maximum supported css->id to USHRT_MAX which should be way above what
is actually useable.
This allows reducing sock->sk_cgrp_prioidx to u16 from u32. The freed
up part will be used to overload the cgroup related fields.
sock->sk_cgrp_prioidx's position is swapped with sk_mark so that the
two cgroup related fields are adjacent.
Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: Daniel Borkmann <daniel@iogearbox.net> CC: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>