Commit 8ab293e3 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:
 "Three late fixes for cgroup: Two cpuset ones, one trivial and the
  other pretty obscure, and a cgroup core fix for a bug which impacts
  cgroup v2 namespace users"

* 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix invalid controller enable rejections with cgroup namespace
  cpuset: fix non static symbol warning
  cpuset: handle race between CPU hotplug and cpuset_hotplug_work
parents 08895a8b 9157056d
......@@ -3446,9 +3446,28 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
* Except for the root, subtree_control must be zero for a cgroup
* with tasks so that child cgroups don't compete against tasks.
*/
if (enable && cgroup_parent(cgrp) && !list_empty(&cgrp->cset_links)) {
ret = -EBUSY;
goto out_unlock;
if (enable && cgroup_parent(cgrp)) {
struct cgrp_cset_link *link;
/*
* Because namespaces pin csets too, @cgrp->cset_links
* might not be empty even when @cgrp is empty. Walk and
* verify each cset.
*/
spin_lock_irq(&css_set_lock);
ret = 0;
list_for_each_entry(link, &cgrp->cset_links, cset_link) {
if (css_set_populated(link->cset)) {
ret = -EBUSY;
break;
}
}
spin_unlock_irq(&css_set_lock);
if (ret)
goto out_unlock;
}
/* save and update control masks and prepare csses */
......@@ -3899,7 +3918,9 @@ void cgroup_file_notify(struct cgroup_file *cfile)
* cgroup_task_count - count the number of tasks in a cgroup.
* @cgrp: the cgroup in question
*
* Return the number of tasks in the cgroup.
* Return the number of tasks in the cgroup. The returned number can be
* higher than the actual number of tasks due to css_set references from
* namespace roots and temporary usages.
*/
static int cgroup_task_count(const struct cgroup *cgrp)
{
......
......@@ -325,8 +325,7 @@ static struct file_system_type cpuset_fs_type = {
/*
* Return in pmask the portion of a cpusets's cpus_allowed that
* are online. If none are online, walk up the cpuset hierarchy
* until we find one that does have some online cpus. The top
* cpuset always has some cpus online.
* until we find one that does have some online cpus.
*
* One way or another, we guarantee to return some non-empty subset
* of cpu_online_mask.
......@@ -335,8 +334,20 @@ static struct file_system_type cpuset_fs_type = {
*/
static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
{
while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask))
while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) {
cs = parent_cs(cs);
if (unlikely(!cs)) {
/*
* The top cpuset doesn't have any online cpu as a
* consequence of a race between cpuset_hotplug_work
* and cpu hotplug notifier. But we know the top
* cpuset's effective_cpus is on its way to to be
* identical to cpu_online_mask.
*/
cpumask_copy(pmask, cpu_online_mask);
return;
}
}
cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
}
......@@ -2074,7 +2085,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
* which could have been changed by cpuset just after it inherits the
* state from the parent and before it sits on the cgroup's task list.
*/
void cpuset_fork(struct task_struct *task)
static void cpuset_fork(struct task_struct *task)
{
if (task_css_is_root(task, cpuset_cgrp_id))
return;
......
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