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Commit d7eeac19 authored by Li Zefan's avatar Li Zefan Committed by Tejun Heo
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cgroup: hold cgroup_mutex before calling css_offline() 



cpuset no longer nests cgroup_mutex inside cpu_hotplug lock, so
we don't have to release cgroup_mutex before calling css_offline().

Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 6dc01181

Documentation/cgroups/cgroups.txt

+1 −0
Original line number Original line Diff line number Diff line
@@ -580,6 +580,7 @@ propagation along the hierarchy. See the comment on 
cgroup_for_each_descendant_pre() for details.

cgroup_for_each_descendant_pre() for details.





void css_offline(struct cgroup *cgrp);

void css_offline(struct cgroup *cgrp);

(cgroup_mutex held by caller)





This is the counterpart of css_online() and called iff css_online()

This is the counterpart of css_online() and called iff css_online()

has succeeded on @cgrp. This signifies the beginning of the end of

has succeeded on @cgrp. This signifies the beginning of the end of

kernel/cgroup.c

+1 −10
Original line number Original line Diff line number Diff line
@@ -4169,17 +4169,8 @@ static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp) 
	if (!(css->flags & CSS_ONLINE))

	if (!(css->flags & CSS_ONLINE))

		return;

		return;





	/*

	if (ss->css_offline)

	 * css_offline() should be called with cgroup_mutex unlocked.  See

	 * 3fa59dfbc3 ("cgroup: fix potential deadlock in pre_destroy") for

	 * details.  This temporary unlocking should go away once

	 * cgroup_mutex is unexported from controllers.

	 */

	if (ss->css_offline) {

		mutex_unlock(&cgroup_mutex);

		ss->css_offline(cgrp);

		ss->css_offline(cgrp);

		mutex_lock(&cgroup_mutex);

	}





	cgrp->subsys[ss->subsys_id]->flags &= ~CSS_ONLINE;

	cgrp->subsys[ss->subsys_id]->flags &= ~CSS_ONLINE;

}

}