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Commit a0a4db54 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
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cgroups: remove events before destroying subsystem state objects 



Events should be removed after rmdir of cgroup directory, but before
destroying subsystem state objects.  Let's take reference to cgroup
directory dentry to do that.

Signed-off-by: default avatarKirill A. Shutemov <kirill@shutemov.name>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Acked-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4ab78683

include/linux/cgroup.h

+0 −3
Original line number Diff line number Diff line
@@ -396,9 +396,6 @@ struct cftype { 
	 * closes the eventfd or on cgroup removing.

	 * This callback must be implemented, if you want provide

	 * notification functionality.

	 *

	 * Be careful. It can be called after destroy(), so you have

	 * to keep all nesessary data, until all events are removed.

	 */

	int (*unregister_event)(struct cgroup *cgrp, struct cftype *cft,

			struct eventfd_ctx *eventfd);

kernel/cgroup.c

+8 −0
Original line number Diff line number Diff line
@@ -2994,6 +2994,7 @@ static void cgroup_event_remove(struct work_struct *work) 


	eventfd_ctx_put(event->eventfd);

	kfree(event);

	dput(cgrp->dentry);

}



/*
@@ -3114,6 +3115,13 @@ static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft, 
		goto fail;

	}



	/*

	 * Events should be removed after rmdir of cgroup directory, but before

	 * destroying subsystem state objects. Let's take reference to cgroup

	 * directory dentry to do that.

	 */

	dget(cgrp->dentry);



	spin_lock(&cgrp->event_list_lock);

	list_add(&event->list, &cgrp->event_list);

	spin_unlock(&cgrp->event_list_lock);

mm/memcontrol.c

+0 −9
Original line number Diff line number Diff line
@@ -3361,12 +3361,6 @@ static int mem_cgroup_register_event(struct cgroup *cgrp, struct cftype *cft, 
		}

	}



	/*

	 * We need to increment refcnt to be sure that all thresholds

	 * will be unregistered before calling __mem_cgroup_free()

	 */

	mem_cgroup_get(memcg);



	if (type == _MEM)

		rcu_assign_pointer(memcg->thresholds, thresholds_new);

	else
@@ -3460,9 +3454,6 @@ assign: 
	/* To be sure that nobody uses thresholds before freeing it */

	synchronize_rcu();



	for (i = 0; i < thresholds->size - size; i++)

		mem_cgroup_put(memcg);



	kfree(thresholds);

unlock:

	mutex_unlock(&memcg->thresholds_lock);