tree 887f0cbc2853802ad113b87f0d2c5b764e2619ce
parent ace2bee8135a3dc725958b8d08c55ee9df813d39
author Tejun Heo <tj@kernel.org> 1392137567 -0500
committer Tejun Heo <tj@kernel.org> 1392137567 -0500

cgroup: release cgroup_mutex over file removals

Now that cftypes and all tree modification operations are protected by
cgroup_tree_mutex, we can drop cgroup_mutex while deleting files and
directories.  Drop cgroup_mutex over removals.

This doesn't make any noticeable difference now but is to help kernfs
conversion.  In kernfs, removals are sync points which drain in-flight
operations as those operations would grab cgroup_mutex, trying to
delete under cgroup_mutex would deadlock.  This can be resolved by
just holding the outer cgroup_tree_mutex which nests outside both
kernfs active reference and cgroup_mutex.

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