cgroup: use bitmask to filter for_each_subsys

[ Upstream commit cb4a316752709be4a644f070440a8be470d92b7d ]

Add a new macro for_each_subsys_which that allows all enabled cgroup
subsystems to be filtered by a bitmask, such that mask & (1 << ssid)
determines if the subsystem is to be processed in the loop body (where
ssid is the unique id of the subsystem).

Also replace the need_forkexit_callback with two separate bitmasks for
each callback to make (ss->{fork,exit}) checks unnecessary.

tj: add a short comment for "if (!CGROUP_SUBSYS_COUNT)".

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

0 files changed, 0 insertions, 0 deletions