linux-stable.git/include/linux/cgroup.h, branch v3.9.8

cgroup: fix a subtle bug in descendant pre-order walk

2013-06-07T19:53:07+00:00

commit 7805d000db30a3787a4c969bab6ae4d8a5fd8ce6 upstream.

When cgroup_next_descendant_pre() initiates a walk, it checks whether
the subtree root doesn't have any children and if not returns NULL.
Later code assumes that the subtree isn't empty.  This is broken
because the subtree may become empty inbetween, which can lead to the
traversal escaping the subtree by walking to the sibling of the
subtree root.

There's no reason to have the early exit path.  Remove it along with
the later assumption that the subtree isn't empty.  This simplifies
the code a bit and fixes the subtle bug.

While at it, fix the comment of cgroup_for_each_descendant_pre() which
was incorrectly referring to ->css_offline() instead of
->css_online().

Signed-off-by: Tejun Heo 
Reviewed-by: Michal Hocko 
Signed-off-by: Greg Kroah-Hartman

cgroup: fix broken file xattrs

2013-05-08T03:33:11+00:00

commit 712317ad97f41e738e1a19aa0a6392a78a84094e upstream.

We should store file xattrs in struct cfent instead of struct cftype,
because cftype is a type while cfent is object instance of cftype.

For example each cgroup has a tasks file, and each tasks file is
associated with a uniq cfent, but all those files share the same
struct cftype.

Alexey Kodanev reported a crash, which can be reproduced:

  # mount -t cgroup -o xattr /sys/fs/cgroup
  # mkdir /sys/fs/cgroup/test
  # setfattr -n trusted.value -v test_value /sys/fs/cgroup/tasks
  # rmdir /sys/fs/cgroup/test
  # umount /sys/fs/cgroup
  oops!

In this case, simple_xattrs_free() will free the same struct simple_xattrs
twice.

tj: Dropped unused local variable @cft from cgroup_diput().

Reported-by: Alexey Kodanev 
Signed-off-by: Li Zefan 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

cgroup: remove synchronize_rcu() from cgroup_diput()

2013-01-24T20:05:18+00:00

Free cgroup via call_rcu(). The actual work is done through
workqueue.

Signed-off-by: Li Zefan 
Signed-off-by: Tejun Heo

cgroup: implement cgroup_rightmost_descendant()

2013-01-07T16:50:28+00:00

Implement cgroup_rightmost_descendant() which returns the right most
descendant of the specified cgroup.  This can be used to skip the
cgroup's subtree while iterating with
cgroup_for_each_descendant_pre().

Signed-off-by: Tejun Heo 
Acked-by: Michal Hocko 
Acked-by: Li Zefan

cgroup: remove unused dummy cgroup_fork_callbacks()

2013-01-07T16:49:16+00:00

5edee61ede ("cgroup: cgroup_subsys->fork() should be called after the
task is added to css_set") removed cgroup_fork_callbacks() but forgot
to remove its dummy version for !CONFIG_CGROUPS.  Remove it.

Signed-off-by: Tejun Heo 
Reported-by: Herton Ronaldo Krzesinski

cgroup: remove obsolete guarantee from cgroup_task_migrate.

2012-11-20T14:44:58+00:00

'guarantee' is already removed from cgroup_task_migrate, so remove
the corresponding comments. Some other typos in cgroup are also
changed.

Cc: Tejun Heo 
Cc: Li Zefan 
Signed-off-by: Tao Ma 
Signed-off-by: Tejun Heo

cgroup: add cgroup->id

2012-11-19T17:02:12+00:00

With the introduction of generic cgroup hierarchy iterators, css_id is
being phased out.  It was unnecessarily complex, id'ing the wrong
thing (cgroups need IDs, not CSSes) and has other oddities like not
being available at ->css_alloc().

This patch adds cgroup->id, which is a simple per-hierarchy
ida-allocated ID which is assigned before ->css_alloc() and released
after ->css_free().

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan 
Acked-by: Neil Horman

cgroup, cpuset: remove cgroup_subsys->post_clone()

2012-11-19T16:13:39+00:00

Currently CGRP_CPUSET_CLONE_CHILDREN triggers ->post_clone().  Now
that clone_children is cpuset specific, there's no reason to have this
rather odd option activation mechanism in cgroup core.  cpuset can
check the flag from its ->css_allocate() and take the necessary
action.

Move cpuset_post_clone() logic to the end of cpuset_css_alloc() and
remove cgroup_subsys->post_clone().

Loosely based on Glauber's "generalize post_clone into post_create"
patch.

Signed-off-by: Tejun Heo 
Original-patch-by: Glauber Costa 
Original-patch: <1351686554-22592-2-git-send-email-glommer@parallels.com>
Acked-by: Serge E. Hallyn 
Acked-by: Li Zefan 
Cc: Glauber Costa

cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/

2012-11-19T16:13:38+00:00

clone_children is only meaningful for cpuset and will stay that way.
Rename the flag to reflect that and update documentation.  Also, drop
clone_children() wrapper in cgroup.c.  The thin wrapper is used only a
few times and one of them will go away soon.

Signed-off-by: Tejun Heo 
Acked-by: Serge E. Hallyn 
Acked-by: Li Zefan 
Cc: Glauber Costa

cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free()

2012-11-19T16:13:38+00:00

Rename cgroup_subsys css lifetime related callbacks to better describe
what their roles are.  Also, update documentation.

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan