cgroup: implement for_each_[builtin_]subsys()
There are quite a few places where all loaded [builtin] subsys are
iterated. Implement for_each_[builtin_]subsys() and replace manual
iterations with those to simplify those places a bit. The new
iterators automatically skip NULL subsystems. This shouldn't cause
any functional difference.
Iteration loops which scan all subsystems and then skipping modular
ones explicitly are converted to use for_each_builtin_subsys().
While at it, reorder variable declarations and adjust whitespaces a
bit in the affected functions.
v2: Add lockdep_assert_held() in for_each_subsys() and add comments
about synchronization as suggested by Li.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
1 file changed