diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f6495f33a355..95362d15128c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4818,6 +4818,29 @@ css_get_next(struct cgroup_subsys *ss, int id, return ret; } +/* + * get corresponding css from file open on cgroupfs directory + */ +struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) +{ + struct cgroup *cgrp; + struct inode *inode; + struct cgroup_subsys_state *css; + + inode = f->f_dentry->d_inode; + /* check in cgroup filesystem dir */ + if (inode->i_op != &cgroup_dir_inode_operations) + return ERR_PTR(-EBADF); + + if (id < 0 || id >= CGROUP_SUBSYS_COUNT) + return ERR_PTR(-EINVAL); + + /* get cgroup */ + cgrp = __d_cgrp(f->f_dentry); + css = cgrp->subsys[id]; + return css ? css : ERR_PTR(-ENOENT); +} + #ifdef CONFIG_CGROUP_DEBUG static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss, struct cgroup *cont) |