[GIT PULL] more cgroup fixes for v3.15-rc5

[Tejun Heo <tj@kernel.org>]

Hello, Linus.

Three more patches to fix cgroup_freezer breakage due to the recent
cgroup internal locking changes - an operation cgroup_freezer was
using now requires sleepable context and cgroup_freezer was invoking
that while holding a spin lock.  cgroup_freezer was using an overly
elaborate hierarchical locking scheme.

While it's possible to convert the hierarchical spinlocks directly to
mutexes, this patch simplifies the overall locking so that it uses a
global mutex.  This has the added benefit of avoiding iterating
potentially huge number of tasks under a spinlock.  While the patch is
on the larger side in the devel cycle, the changes made are mostly
straight-forward and the locking logic is a lot simpler afterwards.

The following changes since commit 36c38fb7144aa941dc072ba8f58b2dbe509c0345:

  blkcg: use trylock on blkcg_pol_mutex in blkcg_reset_stats() (2014-05-05 13:48:18 -0400)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-3.15-fixes

for you to fetch changes up to 36e9d2ebcc15d029b33f42a36146ab5a5bcfcfe7:

  cgroup: fix rcu_read_lock() leak in update_if_frozen() (2014-05-13 11:28:30 -0400)

Thanks.

----------------------------------------------------------------
Tejun Heo (3):
      cgroup: introduce task_css_is_root()
      cgroup_freezer: replace freezer->lock with freezer_mutex
      cgroup: fix rcu_read_lock() leak in update_if_frozen()

 include/linux/cgroup.h  |  15 +++++++
 kernel/cgroup.c         |   2 +-
 kernel/cgroup_freezer.c | 116 ++++++++++++++++++++----------------------------
 3 files changed, 65 insertions(+), 68 deletions(-)

-- 
tejun