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Commit eee03164 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Greg Kroah-Hartman
Browse files

kobject: introduce kobj_completion 



A common way to handle kobject lifetimes in embedded in objects with
different lifetime rules is to pair the kobject with a struct completion.

This introduces a kobj_completion structure that can be used in place
of the pairing, along with several convenience functions for
initialization, release, and put-and-wait.

Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1296fc02

include/linux/kobj_completion.h

0 → 100644
+18 −0
Original line number Diff line number Diff line 
#ifndef _KOBJ_COMPLETION_H_

#define _KOBJ_COMPLETION_H_



#include <linux/kobject.h>

#include <linux/completion.h>



struct kobj_completion {

	struct kobject kc_kobj;

	struct completion kc_unregister;

};



#define kobj_to_kobj_completion(kobj) \

	container_of(kobj, struct kobj_completion, kc_kobj)



void kobj_completion_init(struct kobj_completion *kc, struct kobj_type *ktype);

void kobj_completion_release(struct kobject *kobj);

void kobj_completion_del_and_wait(struct kobj_completion *kc);

#endif /* _KOBJ_COMPLETION_H_ */

lib/kobject.c

+50 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 */



#include <linux/kobject.h>

#include <linux/kobj_completion.h>

#include <linux/string.h>

#include <linux/export.h>

#include <linux/stat.h>
@@ -749,6 +750,55 @@ const struct sysfs_ops kobj_sysfs_ops = { 
	.store	= kobj_attr_store,

};



/**

 * kobj_completion_init - initialize a kobj_completion object.

 * @kc: kobj_completion

 * @ktype: type of kobject to initialize

 *

 * kobj_completion structures can be embedded within structures with different

 * lifetime rules.  During the release of the enclosing object, we can

 * wait on the release of the kobject so that we don't free it while it's

 * still busy.

 */

void kobj_completion_init(struct kobj_completion *kc, struct kobj_type *ktype)

{

	init_completion(&kc->kc_unregister);

	kobject_init(&kc->kc_kobj, ktype);

}

EXPORT_SYMBOL_GPL(kobj_completion_init);



/**

 * kobj_completion_release - release a kobj_completion object

 * @kobj: kobject embedded in kobj_completion

 *

 * Used with kobject_release to notify waiters that the kobject has been

 * released.

 */

void kobj_completion_release(struct kobject *kobj)

{

	struct kobj_completion *kc = kobj_to_kobj_completion(kobj);

	complete(&kc->kc_unregister);

}

EXPORT_SYMBOL_GPL(kobj_completion_release);



/**

 * kobj_completion_del_and_wait - release the kobject and wait for it

 * @kc: kobj_completion object to release

 *

 * Delete the kobject from sysfs and drop the reference count.  Then wait

 * until any other outstanding references are also dropped.  This routine

 * is only necessary once other references may have been taken on the

 * kobject.  Typically this happens when the kobject has been published

 * to sysfs via kobject_add.

 */

void kobj_completion_del_and_wait(struct kobj_completion *kc)

{

	kobject_del(&kc->kc_kobj);

	kobject_put(&kc->kc_kobj);

	wait_for_completion(&kc->kc_unregister);

}

EXPORT_SYMBOL_GPL(kobj_completion_del_and_wait);



/**

 * kset_register - initialize and add a kset.

 * @k: kset.