diff options
| -rw-r--r-- | kernel/cgroup.c | 50 |
1 files changed, 32 insertions, 18 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 8b729c278b64..bc1dcabe9217 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -890,6 +890,16 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode) struct cgroup *cgrp = dentry->d_fsdata; BUG_ON(!(cgroup_is_dead(cgrp))); + + /* + * XXX: cgrp->id is only used to look up css's. As cgroup + * and css's lifetimes will be decoupled, it should be made + * per-subsystem and moved to css->id so that lookups are + * successful until the target css is released. + */ + idr_remove(&cgrp->root->cgroup_idr, cgrp->id); + cgrp->id = -1; + call_rcu(&cgrp->rcu_head, cgroup_free_rcu); } else { struct cfent *cfe = __d_cfe(dentry); @@ -4268,6 +4278,7 @@ static void css_release(struct percpu_ref *ref) struct cgroup_subsys_state *css = container_of(ref, struct cgroup_subsys_state, refcnt); + rcu_assign_pointer(css->cgroup->subsys[css->ss->subsys_id], NULL); call_rcu(&css->rcu_head, css_free_rcu_fn); } @@ -4426,14 +4437,6 @@ 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 and the parent css */ - for_each_root_subsys(root, ss) { - struct cgroup_subsys_state *css = css_ar[ss->subsys_id]; - - dget(dentry); - css_get(css->parent); - } - /* hold a ref to the parent's dentry */ dget(parent->dentry); @@ -4445,6 +4448,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, if (err) goto err_destroy; + /* each css holds a ref to the cgroup's dentry and parent css */ + dget(dentry); + css_get(css->parent); + + /* mark it consumed for error path */ + css_ar[ss->subsys_id] = NULL; + if (ss->broken_hierarchy && !ss->warned_broken_hierarchy && parent->parent) { pr_warning("cgroup: %s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n", @@ -4491,6 +4501,14 @@ err_free_cgrp: return err; err_destroy: + for_each_root_subsys(root, ss) { + struct cgroup_subsys_state *css = css_ar[ss->subsys_id]; + + if (css) { + percpu_ref_cancel_init(&css->refcnt); + ss->css_free(css); + } + } cgroup_destroy_locked(cgrp); mutex_unlock(&cgroup_mutex); mutex_unlock(&dentry->d_inode->i_mutex); @@ -4652,8 +4670,12 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) * will be invoked to perform the rest of destruction once the * percpu refs of all css's are confirmed to be killed. */ - for_each_root_subsys(cgrp->root, ss) - kill_css(cgroup_css(cgrp, ss)); + for_each_root_subsys(cgrp->root, ss) { + struct cgroup_subsys_state *css = cgroup_css(cgrp, ss); + + if (css) + kill_css(css); + } /* * Mark @cgrp dead. This prevents further task migration and child @@ -4722,14 +4744,6 @@ static void cgroup_destroy_css_killed(struct cgroup *cgrp) /* delete this cgroup from parent->children */ list_del_rcu(&cgrp->sibling); - /* - * We should remove the cgroup object from idr before its grace - * period starts, so we won't be looking up a cgroup while the - * cgroup is being freed. - */ - idr_remove(&cgrp->root->cgroup_idr, cgrp->id); - cgrp->id = -1; - dput(d); set_bit(CGRP_RELEASABLE, &parent->flags); |