Commit eb6fd504 authored by Tejun Heo's avatar Tejun Heo

cgroup: use rculist ops for cgroup->children

Use RCU safe list operations for cgroup->children.  This will be used
to implement cgroup children / descendant walking which can be used by
controllers.

Note that cgroup_create() now puts a new cgroup at the end of the
->children list instead of head.  This isn't strictly necessary but is
done so that the iteration order is more conventional.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent a8638030
...@@ -12,6 +12,7 @@ ...@@ -12,6 +12,7 @@
#include <linux/cpumask.h> #include <linux/cpumask.h>
#include <linux/nodemask.h> #include <linux/nodemask.h>
#include <linux/rcupdate.h> #include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/cgroupstats.h> #include <linux/cgroupstats.h>
#include <linux/prio_heap.h> #include <linux/prio_heap.h>
#include <linux/rwsem.h> #include <linux/rwsem.h>
......
...@@ -1650,7 +1650,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, ...@@ -1650,7 +1650,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
free_cg_links(&tmp_cg_links); free_cg_links(&tmp_cg_links);
BUG_ON(!list_empty(&root_cgrp->sibling));
BUG_ON(!list_empty(&root_cgrp->children)); BUG_ON(!list_empty(&root_cgrp->children));
BUG_ON(root->number_of_cgroups != 1); BUG_ON(root->number_of_cgroups != 1);
...@@ -1699,7 +1698,6 @@ static void cgroup_kill_sb(struct super_block *sb) { ...@@ -1699,7 +1698,6 @@ static void cgroup_kill_sb(struct super_block *sb) {
BUG_ON(root->number_of_cgroups != 1); BUG_ON(root->number_of_cgroups != 1);
BUG_ON(!list_empty(&cgrp->children)); BUG_ON(!list_empty(&cgrp->children));
BUG_ON(!list_empty(&cgrp->sibling));
mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_mutex);
mutex_lock(&cgroup_root_mutex); mutex_lock(&cgroup_root_mutex);
...@@ -4052,7 +4050,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, ...@@ -4052,7 +4050,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
} }
} }
list_add(&cgrp->sibling, &cgrp->parent->children); list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children);
root->number_of_cgroups++; root->number_of_cgroups++;
err = cgroup_create_dir(cgrp, dentry, mode); err = cgroup_create_dir(cgrp, dentry, mode);
...@@ -4083,7 +4081,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, ...@@ -4083,7 +4081,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
err_remove: err_remove:
list_del(&cgrp->sibling); list_del_rcu(&cgrp->sibling);
root->number_of_cgroups--; root->number_of_cgroups--;
err_destroy: err_destroy:
...@@ -4209,7 +4207,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) ...@@ -4209,7 +4207,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
raw_spin_unlock(&release_list_lock); raw_spin_unlock(&release_list_lock);
/* delete this cgroup from parent->children */ /* delete this cgroup from parent->children */
list_del_init(&cgrp->sibling); list_del_rcu(&cgrp->sibling);
list_del_init(&cgrp->allcg_node); list_del_init(&cgrp->allcg_node);
......
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