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authorJeff Mahoney <jeffm@suse.com>2013-09-11 13:00:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 16:17:33 -0700
commiteee031649707db3c9920d9498f8d03819b74fc23 (patch)
tree439bd4f3db8c3f4342a85b93a6cec1c8db4e524c /lib/kobject.c
parent1296fc02c22cb8bc0cde34fbd1336d1a8d76f1e1 (diff)
downloadlinux-stericsson-eee031649707db3c9920d9498f8d03819b74fc23.tar.gz
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 <jeffm@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/kobject.c')
-rw-r--r--lib/kobject.c50
1 files changed, 50 insertions, 0 deletions
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 <linux/kobject.h>
+#include <linux/kobj_completion.h>
#include <linux/string.h>
#include <linux/export.h>
#include <linux/stat.h>
@@ -750,6 +751,55 @@ const struct sysfs_ops kobj_sysfs_ops = {
};
/**
+ * 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.
*/