Commit 3c14f8b4 authored by Tejun Heo's avatar Tejun Heo

cgroup: move subsys file removal to kill_css()

With the planned unified hierarchy, individual css's will be created
and destroyed dynamically across the lifetime of a cgroup.  To enable
such usages, css destruction is being decoupled from cgroup
destruction.  This patch moves subsys file removal from
cgroup_destroy_locked() to kill_css().

While this changes the order of destruction operations, the changes
shouldn't be noticeable to cgroup subsystems or userland.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent edae0c33
......@@ -4599,13 +4599,15 @@ static void css_killed_ref_fn(struct percpu_ref *ref)
* kill_css - destroy a css
* @css: css to destroy
*
* This function initiates destruction of @css by putting its base
* reference. ->css_offline() will be invoked asynchronously once
* css_tryget() is guaranteed to fail and when the reference count reaches
* zero, @css will be released.
* This function initiates destruction of @css by removing cgroup interface
* files and putting its base reference. ->css_offline() will be invoked
* asynchronously once css_tryget() is guaranteed to fail and when the
* reference count reaches zero, @css will be released.
*/
static void kill_css(struct cgroup_subsys_state *css)
{
cgroup_clear_dir(css->cgroup, 1 << css->ss->subsys_id);
/*
* Killing would put the base ref, but we need to keep it alive
* until after ->css_offline().
......@@ -4703,10 +4705,10 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
cgroup_destroy_css_killed(cgrp);
/*
* Clear and remove @cgrp directory. The removal puts the base ref
* but we aren't quite done with @cgrp yet, so hold onto it.
* Clear the base files and remove @cgrp directory. The removal
* puts the base ref but we aren't quite done with @cgrp yet, so
* hold onto it.
*/
cgroup_clear_dir(cgrp, cgrp->root->subsys_mask);
cgroup_addrm_files(cgrp, cgroup_base_files, false);
dget(d);
cgroup_d_remove_dir(d);
......
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