From eee031649707db3c9920d9498f8d03819b74fc23 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Wed, 11 Sep 2013 13:00:30 -0400 Subject: 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: Jeff Mahoney Signed-off-by: Greg Kroah-Hartman --- lib/kobject.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) (limited to 'lib/kobject.c') diff --git a/lib/kobject.c b/lib/kobject.c index e769ee3c2fb9..a5a9b13b0648 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -13,6 +13,7 @@ */ #include +#include #include #include #include @@ -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. -- cgit v1.2.3