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| author | Tejun Heo <tj@kernel.org> | 2013-04-14 20:50:08 -0700 |
|---|---|---|
| committer | Maciej Wereski <m.wereski@partner.samsung.com> | 2014-12-22 09:16:48 +0100 |
| commit | c041e2cd281c85e7e66fc2ab0e6e2c8b37d97977 (patch) | |
| tree | c2c11a197682b0cea6fdbd6897b792ca2afb63a5 | |
| parent | eed4bbdc4a0ae13b806e4f8d28acfbab9b7d008b (diff) | |
| download | linux-3.10-c041e2cd281c85e7e66fc2ab0e6e2c8b37d97977.tar.gz linux-3.10-c041e2cd281c85e7e66fc2ab0e6e2c8b37d97977.tar.bz2 linux-3.10-c041e2cd281c85e7e66fc2ab0e6e2c8b37d97977.zip | |
cgroup: implement task_cgroup_path_from_hierarchy()
kdbus folks want a sane way to determine the cgroup path that a given
task belongs to on a given hierarchy, which is a reasonble thing to
expect from cgroup core.
Implement task_cgroup_path_from_hierarchy().
v2: Dropped unnecessary NULL check on the return value of
task_cgroup_from_root() as suggested by Li Zefan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <greg@kroah.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Daniel Mack <daniel@zonque.org>
| -rw-r--r-- | include/linux/cgroup.h | 2 | ||||
| -rw-r--r-- | kernel/cgroup.c | 32 |
2 files changed, 34 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 8852d370c72..5982ebf66ae 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -542,6 +542,8 @@ int cgroup_is_removed(const struct cgroup *cgrp); bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor); int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen); +int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id, + char *buf, size_t buflen); int cgroup_task_count(const struct cgroup *cgrp); diff --git a/kernel/cgroup.c b/kernel/cgroup.c index d9acb5236d5..2b6fafd77a2 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1838,6 +1838,38 @@ out: } EXPORT_SYMBOL_GPL(cgroup_path); +/** + * task_cgroup_path_from_hierarchy - cgroup path of a task on a hierarchy + * @task: target task + * @hierarchy_id: the hierarchy to look up @task's cgroup from + * @buf: the buffer to write the path into + * @buflen: the length of the buffer + * + * Determine @task's cgroup on the hierarchy specified by @hierarchy_id and + * copy its path into @buf. This function grabs cgroup_mutex and shouldn't + * be used inside locks used by cgroup controller callbacks. + */ +int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id, + char *buf, size_t buflen) +{ + struct cgroupfs_root *root; + struct cgroup *cgrp = NULL; + int ret = -ENOENT; + + mutex_lock(&cgroup_mutex); + + root = idr_find(&cgroup_hierarchy_idr, hierarchy_id); + if (root) { + cgrp = task_cgroup_from_root(task, root); + ret = cgroup_path(cgrp, buf, buflen); + } + + mutex_unlock(&cgroup_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy); + /* * Control Group taskset */ |