cgroup: remove css_parent()

cgroup in general is moving towards using cgroup_subsys_state as the
fundamental structural component and css_parent() was introduced to
convert from using cgroup->parent to css->parent.  It was quite some
time ago and we're moving forward with making css more prominent.

This patch drops the trivial wrapper css_parent() and let the users
dereference css->parent.  While at it, explicitly mark fields of css
which are public and immutable.

v2: New usage from device_cgroup.c converted.

Signed-off-by: Tejun Heo <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Neil Horman <[email protected]>
Acked-by: "David S. Miller" <[email protected]>
Acked-by: Li Zefan <[email protected]>
Cc: Vivek Goyal <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Johannes Weiner <[email protected]>

0 files changed, 0 insertions, 0 deletions