[GIT PULL] cgroup fixes for v4.13-rc3

[Tejun Heo]

Hello, Linus.

Several cgroup bug fixes.

* cgroup core was calling a migration callback on empty migrations,
  which could make cpuset crash.

* There was a very subtle bug where the controller interface files
  aren't created directly when cgroup2 is mounted.  Because later
  operations create them, this bug didn't get noticed earlier.

* Failed writes to cgroup.subtree_control were incorrectly returning
  0.

The following changes since commit cee37d83e6d9ada1c2254c73bac7955f9e048d22:

  Merge branch 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs (2017-07-07 21:48:15 -0700)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-4.13-fixes

for you to fetch changes up to 3c74541777302eec43a0d1327c4d58b8659a776b:

  cgroup: fix error return value from cgroup_subtree_control() (2017-07-23 08:15:17 -0400)

----------------------------------------------------------------
Tejun Heo (3):
      cgroup: don't call migration methods if there are no tasks to migrate
      cgroup: create dfl_root files on subsys registration
      cgroup: fix error return value from cgroup_subtree_control()

 kernel/cgroup/cgroup-internal.h |  3 ++
 kernel/cgroup/cgroup.c          | 66 +++++++++++++++++++++++------------------
 2 files changed, 40 insertions(+), 29 deletions(-)

--
tejun