tree ca93a1567a9e07adec09a3384d23536dca44603f
parent 47cfcd0922454e49f4923b1e2d31a5bf199237c3
author Tejun Heo <tj@kernel.org> 1365352191 -0700
committer Tejun Heo <tj@kernel.org> 1365352191 -0700

cgroup: remove cgroup_lock_is_held()

We don't want controllers to assume that the information is officially
available and do funky things with it.

The only user is task_subsys_state_check() which uses it to verify RCU
access context.  We can move cgroup_lock_is_held() inside
CONFIG_PROVE_RCU but that doesn't add meaningful protection compared
to conditionally exposing cgroup_mutex.

Remove cgroup_lock_is_held(), export cgroup_mutex iff CONFIG_PROVE_RCU
and use lockdep_is_held() directly on the mutex in
task_subsys_state_check().

While at it, add parentheses around macro arguments in
task_subsys_state_check().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>