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authorGrzegorz Nosek <root@localdomain.pl>2009-04-02 16:57:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-02 19:04:53 -0700
commit313e924c0852943e67335fad9d2608701f0dfe8e (patch)
treefa4c3f65a7ed6edea52ae78b012138ebab1420c3 /kernel/cgroup.c
parentd20a390a0ee2bf2f692c539c6ce1c829e1080bb5 (diff)
downloadlinux-313e924c0852943e67335fad9d2608701f0dfe8e.tar.bz2
cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups
The ns_proxy cgroup allows moving processes to child cgroups only one level deep at a time. This commit relaxes this restriction and makes it possible to attach tasks directly to grandchild cgroups, e.g.: ($pid is in the root cgroup) echo $pid > /cgroup/CG1/CG2/tasks Previously this operation would fail with -EPERM and would have to be performed as two steps: echo $pid > /cgroup/CG1/tasks echo $pid > /cgroup/CG1/CG2/tasks Also, the target cgroup no longer needs to be empty to move a task there. Signed-off-by: Grzegorz Nosek <root@localdomain.pl> Acked-by: Serge Hallyn <serue@us.ibm.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c500ca7239b2..27792bcb0758 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3084,18 +3084,19 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
}
/**
- * cgroup_is_descendant - see if @cgrp is a descendant of current task's cgrp
+ * cgroup_is_descendant - see if @cgrp is a descendant of @task's cgrp
* @cgrp: the cgroup in question
+ * @task: the task in question
*
- * See if @cgrp is a descendant of the current task's cgroup in
- * the appropriate hierarchy.
+ * See if @cgrp is a descendant of @task's cgroup in the appropriate
+ * hierarchy.
*
* If we are sending in dummytop, then presumably we are creating
* the top cgroup in the subsystem.
*
* Called only by the ns (nsproxy) cgroup.
*/
-int cgroup_is_descendant(const struct cgroup *cgrp)
+int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task)
{
int ret;
struct cgroup *target;
@@ -3105,7 +3106,7 @@ int cgroup_is_descendant(const struct cgroup *cgrp)
return 1;
get_first_subsys(cgrp, NULL, &subsys_id);
- target = task_cgroup(current, subsys_id);
+ target = task_cgroup(task, subsys_id);
while (cgrp != target && cgrp!= cgrp->top_cgroup)
cgrp = cgrp->parent;
ret = (cgrp == target);