diff options
| -rw-r--r-- | include/linux/cgroup.h | 13 | ||||
| -rw-r--r-- | kernel/cgroup.c | 18 |
2 files changed, 19 insertions, 12 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 12d66fee26f8..8a5dc91fbaad 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -75,6 +75,9 @@ struct cgroup_subsys_state { /* reference count - access via css_[try]get() and css_put() */ struct percpu_ref refcnt; + /* the parent css */ + struct cgroup_subsys_state *parent; + unsigned long flags; /* ID for this css, if possible */ struct css_id __rcu *id; @@ -666,15 +669,7 @@ struct cgroup_subsys { static inline struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css) { - struct cgroup *parent_cgrp = css->cgroup->parent; - - if (!parent_cgrp) - return NULL; - - if (css->ss) - return parent_cgrp->subsys[css->ss->subsys_id]; - else - return &parent_cgrp->dummy_css; + return css->parent; } /** diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 0b280978f097..5c6dd7ed26a7 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4264,6 +4264,9 @@ static void css_free_work_fn(struct work_struct *work) struct cgroup_subsys_state *css = container_of(work, struct cgroup_subsys_state, destroy_work); + if (css->parent) + css_put(css->parent); + cgroup_dput(css->cgroup); } @@ -4290,8 +4293,12 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, css->ss = ss; css->flags = 0; css->id = NULL; - if (cgrp == cgroup_dummy_top) + + if (cgrp->parent) + css->parent = cgroup_css(cgrp->parent, ss->subsys_id); + else css->flags |= CSS_ROOT; + BUG_ON(cgroup_css(cgrp, ss->subsys_id)); cgrp->subsys[ss->subsys_id] = css; } @@ -4388,6 +4395,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, cgrp->dentry = dentry; cgrp->parent = parent; + cgrp->dummy_css.parent = &parent->dummy_css; cgrp->root = parent->root; if (notify_on_release(parent)) @@ -4436,9 +4444,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children); root->number_of_cgroups++; - /* each css holds a ref to the cgroup's dentry */ - for_each_root_subsys(root, ss) + /* each css holds a ref to the cgroup's dentry and the parent css */ + for_each_root_subsys(root, ss) { + struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + dget(dentry); + percpu_ref_get(&css->parent->refcnt); + } /* hold a ref to the parent's dentry */ dget(parent->dentry); |