spin_unlock_bh(&cgroup_idr_lock);
}
+static struct cgroup *cgroup_parent(struct cgroup *cgrp)
+{
+ struct cgroup_subsys_state *parent_css = cgrp->self.parent;
+
+ if (parent_css)
+ return container_of(parent_css, struct cgroup, self);
+ return NULL;
+}
+
/**
* cgroup_css - obtain a cgroup's css for the specified subsystem
* @cgrp: the cgroup of interest
if (!(cgrp->root->subsys_mask & (1 << ss->id)))
return NULL;
- while (cgrp->parent &&
- !(cgrp->parent->child_subsys_mask & (1 << ss->id)))
- cgrp = cgrp->parent;
+ while (cgroup_parent(cgrp) &&
+ !(cgroup_parent(cgrp)->child_subsys_mask & (1 << ss->id)))
+ cgrp = cgroup_parent(cgrp);
return cgroup_css(cgrp, ss);
}
while (cgrp) {
if (cgrp == ancestor)
return true;
- cgrp = cgrp->parent;
+ cgrp = cgroup_parent(cgrp);
}
return false;
}
/* 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); })) \
; \
if (cgrp->populated_kn)
kernfs_notify(cgrp->populated_kn);
- cgrp = cgrp->parent;
+ cgrp = cgroup_parent(cgrp);
} while (cgrp);
}
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);
}
/* 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;
}
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);
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);
* Except for the root, child_subsys_mask must be zero for a cgroup
* with tasks so that child cgroups don't compete against tasks.
*/
- if (dst_cgrp && cgroup_on_dfl(dst_cgrp) && dst_cgrp->parent &&
+ if (dst_cgrp && cgroup_on_dfl(dst_cgrp) && cgroup_parent(dst_cgrp) &&
dst_cgrp->child_subsys_mask)
return -EBUSY;
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
- cgroup_print_ss_mask(seq, cgrp->parent->child_subsys_mask);
+ cgroup_print_ss_mask(seq, cgroup_parent(cgrp)->child_subsys_mask);
return 0;
}
/* unavailable or not enabled on the parent? */
if (!(cgrp_dfl_root.subsys_mask & (1 << ssid)) ||
- (cgrp->parent &&
- !(cgrp->parent->child_subsys_mask & (1 << ssid)))) {
+ (cgroup_parent(cgrp) &&
+ !(cgroup_parent(cgrp)->child_subsys_mask & (1 << ssid)))) {
ret = -ENOENT;
goto out_unlock;
}
* Except for the root, child_subsys_mask must be zero for a cgroup
* with tasks so that child cgroups don't compete against tasks.
*/
- if (enable && cgrp->parent && !list_empty(&cgrp->cset_links)) {
+ if (enable && cgroup_parent(cgrp) && !list_empty(&cgrp->cset_links)) {
ret = -EBUSY;
goto out_unlock;
}
continue;
if ((cft->flags & CFTYPE_INSANE) && cgroup_sane_behavior(cgrp))
continue;
- if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgrp->parent)
+ if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgroup_parent(cgrp))
continue;
- if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgrp->parent)
+ if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgroup_parent(cgrp))
continue;
if (is_add) {
* 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;
}
* 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;
}
/* no child, visit my or the closest ancestor's next sibling */
while (pos != root) {
- next = css_next_child(pos, css_parent(pos));
+ next = css_next_child(pos, pos->parent);
if (next)
return next;
- pos = css_parent(pos);
+ pos = pos->parent;
}
return NULL;
return NULL;
/* if there's an unvisited sibling, visit its leftmost descendant */
- next = css_next_child(pos, css_parent(pos));
+ next = css_next_child(pos, pos->parent);
if (next)
return css_leftmost_descendant(next);
/* no sibling left, visit parent */
- return css_parent(pos);
+ return pos->parent;
}
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;
atomic_dec(&cgrp->root->nr_cgrps);
cgroup_pidlist_destroy_all(cgrp);
- if (cgrp->parent) {
+ if (cgroup_parent(cgrp)) {
/*
* We get a ref to the parent, and put the ref when
* this cgroup is being freed, so it's guaranteed
* that the parent won't be destroyed before its
* children.
*/
- cgroup_put(cgrp->parent);
+ cgroup_put(cgroup_parent(cgrp));
kernfs_put(cgrp->kn);
kfree(cgrp);
} else {
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);
}
{
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 (cgrp->parent) {
- css->parent = cgroup_css(cgrp->parent, ss);
+ if (cgroup_parent(cgrp)) {
+ css->parent = cgroup_css(cgroup_parent(cgrp), ss);
css_get(css->parent);
}
*/
static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
{
- struct cgroup *parent = cgrp->parent;
+ 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);
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 &&
- parent->parent) {
+ cgroup_parent(parent)) {
pr_warn("%s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",
current->comm, current->pid, ss->name);
if (!strcmp(ss->name, "memory"))
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);
init_cgroup_housekeeping(cgrp);
- cgrp->parent = parent;
cgrp->self.parent = &parent->self;
cgrp->root = root;
cgrp->serial_nr = cgroup_serial_nr_next++;
/* allocation complete, commit to creation */
- list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children);
+ list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);
atomic_inc(&root->nr_cgrps);
cgroup_get(parent);
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;
*/
kernfs_remove(cgrp->kn);
- set_bit(CGRP_RELEASABLE, &cgrp->parent->flags);
- check_for_release(cgrp->parent);
+ set_bit(CGRP_RELEASABLE, &cgroup_parent(cgrp)->flags);
+ check_for_release(cgroup_parent(cgrp));
/* put the base reference */
percpu_ref_kill(&cgrp->self.refcnt);
/* We don't handle early failures gracefully */
BUG_ON(IS_ERR(css));
init_and_link_css(css, ss, &cgrp_dfl_root.cgrp);
+
+ /*
+ * Root csses are never destroyed and we can't initialize
+ * percpu_ref during early init. Disable refcnting.
+ */
+ css->flags |= CSS_NO_REF;
+
if (early) {
/* allocation can't be done safely during early init */
css->id = 1;
} else {
- BUG_ON(percpu_ref_init(&css->refcnt, css_release));
css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL);
BUG_ON(css->id < 0);
}
int i;
init_cgroup_root(&cgrp_dfl_root, &opts);
+ cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF;
+
RCU_INIT_POINTER(init_task.cgroups, &init_css_set);
for_each_subsys(ss, i) {
struct cgroup_subsys_state *css =
init_css_set.subsys[ss->id];
- BUG_ON(percpu_ref_init(&css->refcnt, css_release));
css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2,
GFP_KERNEL);
BUG_ON(css->id < 0);
projects / linux-beck.git / blobdiff