cgroup: link all cgroup_subsys_states in their sibling lists

[linux-beck.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 8c67a739aea46ec70d3bfd0ed2e4e44b5197f159..dcb06e181ce4f6178a02bd82e3bc6d898faf533b 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -378,7 +378,7 @@ static int notify_on_release(const struct cgroup *cgrp)
 
 /* iterate over child cgrps, lock should be held throughout iteration */
 #define cgroup_for_each_live_child(child, cgrp)                                \
-       list_for_each_entry((child), &(cgrp)->children, sibling)        \
+       list_for_each_entry((child), &(cgrp)->self.children, self.sibling) \
                if (({ lockdep_assert_held(&cgroup_mutex);              \
                       cgroup_is_dead(child); }))                       \
                        ;                                               \
@@ -870,7 +870,7 @@ static void cgroup_destroy_root(struct cgroup_root *root)
        mutex_lock(&cgroup_mutex);
 
        BUG_ON(atomic_read(&root->nr_cgrps));
-       BUG_ON(!list_empty(&cgrp->children));
+       BUG_ON(!list_empty(&cgrp->self.children));
 
        /* Rebind all subsystems back to the default hierarchy */
        rebind_subsystems(&cgrp_dfl_root, root->subsys_mask);
@@ -1432,7 +1432,7 @@ static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data)
        }
 
        /* remounting is not allowed for populated hierarchies */
-       if (!list_empty(&root->cgrp.children)) {
+       if (!list_empty(&root->cgrp.self.children)) {
                ret = -EBUSY;
                goto out_unlock;
        }
@@ -1512,8 +1512,8 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
        struct cgroup_subsys *ss;
        int ssid;
 
-       INIT_LIST_HEAD(&cgrp->sibling);
-       INIT_LIST_HEAD(&cgrp->children);
+       INIT_LIST_HEAD(&cgrp->self.sibling);
+       INIT_LIST_HEAD(&cgrp->self.children);
        INIT_LIST_HEAD(&cgrp->cset_links);
        INIT_LIST_HEAD(&cgrp->release_list);
        INIT_LIST_HEAD(&cgrp->pidlists);
@@ -1612,7 +1612,7 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned int ss_mask)
                link_css_set(&tmp_links, cset, root_cgrp);
        up_write(&css_set_rwsem);
 
-       BUG_ON(!list_empty(&root_cgrp->children));
+       BUG_ON(!list_empty(&root_cgrp->self.children));
        BUG_ON(atomic_read(&root->nr_cgrps) != 1);
 
        kernfs_activate(root_cgrp->kn);
@@ -3128,11 +3128,11 @@ css_next_child(struct cgroup_subsys_state *pos_css,
         * cgroup is removed or iteration and removal race.
         */
        if (!pos) {
-               next = list_entry_rcu(cgrp->children.next, struct cgroup, sibling);
+               next = list_entry_rcu(cgrp->self.children.next, struct cgroup, self.sibling);
        } else if (likely(!cgroup_is_dead(pos))) {
-               next = list_entry_rcu(pos->sibling.next, struct cgroup, sibling);
+               next = list_entry_rcu(pos->self.sibling.next, struct cgroup, self.sibling);
        } else {
-               list_for_each_entry_rcu(next, &cgrp->children, sibling)
+               list_for_each_entry_rcu(next, &cgrp->self.children, self.sibling)
                        if (next->serial_nr > pos->serial_nr)
                                break;
        }
@@ -3142,12 +3142,12 @@ css_next_child(struct cgroup_subsys_state *pos_css,
         * the next sibling; however, it might have @ss disabled.  If so,
         * fast-forward to the next enabled one.
         */
-       while (&next->sibling != &cgrp->children) {
+       while (&next->self.sibling != &cgrp->self.children) {
                struct cgroup_subsys_state *next_css = cgroup_css(next, parent_css->ss);
 
                if (next_css)
                        return next_css;
-               next = list_entry_rcu(next->sibling.next, struct cgroup, sibling);
+               next = list_entry_rcu(next->self.sibling.next, struct cgroup, self.sibling);
        }
        return NULL;
 }
@@ -3283,7 +3283,7 @@ static bool cgroup_has_live_children(struct cgroup *cgrp)
        struct cgroup *child;
 
        rcu_read_lock();
-       list_for_each_entry_rcu(child, &cgrp->children, sibling) {
+       list_for_each_entry_rcu(child, &cgrp->self.children, self.sibling) {
                if (!cgroup_is_dead(child)) {
                        rcu_read_unlock();
                        return true;
@@ -4138,19 +4138,21 @@ static void css_release_work_fn(struct work_struct *work)
        struct cgroup_subsys *ss = css->ss;
        struct cgroup *cgrp = css->cgroup;
 
+       mutex_lock(&cgroup_mutex);
+
+       list_del_rcu(&css->sibling);
+
        if (ss) {
                /* css release path */
                cgroup_idr_remove(&ss->css_idr, css->id);
        } else {
                /* cgroup release path */
-               mutex_lock(&cgroup_mutex);
-               list_del_rcu(&cgrp->sibling);
-               mutex_unlock(&cgroup_mutex);
-
                cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
                cgrp->id = -1;
        }
 
+       mutex_unlock(&cgroup_mutex);
+
        call_rcu(&css->rcu_head, css_free_rcu_fn);
 }
 
@@ -4168,9 +4170,11 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
 {
        cgroup_get(cgrp);
 
+       memset(css, 0, sizeof(*css));
        css->cgroup = cgrp;
        css->ss = ss;
-       css->flags = 0;
+       INIT_LIST_HEAD(&css->sibling);
+       INIT_LIST_HEAD(&css->children);
 
        if (cgroup_parent(cgrp)) {
                css->parent = cgroup_css(cgroup_parent(cgrp), ss);
@@ -4228,12 +4232,13 @@ static void offline_css(struct cgroup_subsys_state *css)
 static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
 {
        struct cgroup *parent = cgroup_parent(cgrp);
+       struct cgroup_subsys_state *parent_css = cgroup_css(parent, ss);
        struct cgroup_subsys_state *css;
        int err;
 
        lockdep_assert_held(&cgroup_mutex);
 
-       css = ss->css_alloc(cgroup_css(parent, ss));
+       css = ss->css_alloc(parent_css);
        if (IS_ERR(css))
                return PTR_ERR(css);
 
@@ -4253,11 +4258,12 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
                goto err_free_id;
 
        /* @css is ready to be brought online now, make it visible */
+       list_add_tail_rcu(&css->sibling, &parent_css->children);
        cgroup_idr_replace(&ss->css_idr, css, css->id);
 
        err = online_css(css);
        if (err)
-               goto err_clear_dir;
+               goto err_list_del;
 
        if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&
            cgroup_parent(parent)) {
@@ -4270,7 +4276,8 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
 
        return 0;
 
-err_clear_dir:
+err_list_del:
+       list_del_rcu(&css->sibling);
        cgroup_clear_dir(css->cgroup, 1 << css->ss->id);
 err_free_id:
        cgroup_idr_remove(&ss->css_idr, css->id);
@@ -4344,7 +4351,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
        cgrp->serial_nr = cgroup_serial_nr_next++;
 
        /* allocation complete, commit to creation */
-       list_add_tail_rcu(&cgrp->sibling, &cgroup_parent(cgrp)->children);
+       list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);
        atomic_inc(&root->nr_cgrps);
        cgroup_get(parent);
 
@@ -4507,9 +4514,9 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
                return -EBUSY;
 
        /*
-        * Make sure there's no live children.  We can't test ->children
-        * emptiness as dead children linger on it while being destroyed;
-        * otherwise, "rmdir parent/child parent" may fail with -EBUSY.
+        * Make sure there's no live children.  We can't test emptiness of
+        * ->self.children as dead children linger on it while being
+        * drained; otherwise, "rmdir parent/child parent" may fail.
         */
        if (cgroup_has_live_children(cgrp))
                return -EBUSY;