tree 9eacd31f55f9f513240739d04a3ee0bfd02cf5ff
parent 58cdb1ceb15aab7b34719ad225ff023775d774e7
author Tejun Heo <tj@kernel.org> 1457455885 -0500
committer Tejun Heo <tj@kernel.org> 1457455885 -0500

cgroup: move migration destination verification out of cgroup_migrate_prepare_dst()

cgroup_migrate_prepare_dst() verifies whether the destination cgroup
is allowable; however, the test doesn't really belong there.  It's too
deep and common in the stack and as a result the test itself is gated
by another test.

Separate the test out into cgroup_may_migrate_to() and update
cgroup_attach_task() and cgroup_transfer_tasks() to perform the test
directly.  This doesn't cause any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>