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| author | Li Zefan <lizefan@huawei.com> | 2013-08-19 10:05:24 +0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-08-19 09:52:18 -0400 |
| commit | 1cb650b91ba582f6737457b7d22e368585596d2c (patch) | |
| tree | 1a3d8d4a219dcca229dcc6dc47876091ef0f8438 /kernel/cgroup.c | |
| parent | 930913a31289202d232186b82854b26d7fb7cf4d (diff) | |
| download | lwn-1cb650b91ba582f6737457b7d22e368585596d2c.tar.gz lwn-1cb650b91ba582f6737457b7d22e368585596d2c.zip | |
cgroup: change cgroup_from_id() to css_from_id()
Now we want cgroup core to always provide the css to use to the
subsystems, so change this API to css_from_id().
Uninline css_from_id(), because it's getting bigger and cgroup_css()
has been unexported.
While at it, remove the #ifdef, and shuffle the order of the args.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index b69b572131e5..ff7d642a070a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5717,6 +5717,28 @@ struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) return css ? css : ERR_PTR(-ENOENT); } +/** + * css_from_id - lookup css by id + * @id: the cgroup id + * @ss: cgroup subsys to be looked into + * + * Returns the css if there's valid one with @id, otherwise returns NULL. + * Should be called under rcu_read_lock(). + */ +struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss) +{ + struct cgroup *cgrp; + + rcu_lockdep_assert(rcu_read_lock_held() || + lockdep_is_held(&cgroup_mutex), + "css_from_id() needs proper protection"); + + cgrp = idr_find(&ss->root->cgroup_idr, id); + if (cgrp) + return cgroup_css(cgrp, ss->subsys_id); + return NULL; +} + #ifdef CONFIG_CGROUP_DEBUG static struct cgroup_subsys_state * debug_css_alloc(struct cgroup_subsys_state *parent_css) |