kobject: introduce kobj_completion

[deliverable/linux.git] / lib / kobject.c

diff --git a/lib/kobject.c b/lib/kobject.c
index 1d46c151a4aea8ca741623931bba5d737ac5bc64..a5a9b13b064860052d48fe640d019a69dc4c9d50 100644 (file)
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -13,11 +13,33 @@
  */
 
 #include <linux/kobject.h>
+#include <linux/kobj_completion.h>
 #include <linux/string.h>
 #include <linux/export.h>
 #include <linux/stat.h>
 #include <linux/slab.h>
 
+/**
+ * kobject_namespace - return @kobj's namespace tag
+ * @kobj: kobject in question
+ *
+ * Returns namespace tag of @kobj if its parent has namespace ops enabled
+ * and thus @kobj should have a namespace tag associated with it.  Returns
+ * %NULL otherwise.
+ */
+const void *kobject_namespace(struct kobject *kobj)
+{
+       const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
+       const void *ns;
+
+       if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
+               return NULL;
+
+       ns = kobj->ktype->namespace(kobj);
+       WARN_ON(!ns);   /* @kobj in a namespace is required to have !NULL tag */
+       return ns;
+}
+
 /*
  * populate_dir - populate directory with attributes.
  * @kobj: object we're working on.
@@ -46,8 +68,9 @@ static int populate_dir(struct kobject *kobj)
 
 static int create_dir(struct kobject *kobj)
 {
-       int error = 0;
-       error = sysfs_create_dir(kobj);
+       int error;
+
+       error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
        if (!error) {
                error = populate_dir(kobj);
                if (error)
@@ -428,7 +451,7 @@ int kobject_rename(struct kobject *kobj, const char *new_name)
                goto out;
        }
 
-       error = sysfs_rename_dir(kobj, new_name);
+       error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
        if (error)
                goto out;
 
@@ -472,6 +495,7 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent)
                if (kobj->kset)
                        new_parent = kobject_get(&kobj->kset->kobj);
        }
+
        /* old object path */
        devpath = kobject_get_path(kobj, GFP_KERNEL);
        if (!devpath) {
@@ -486,7 +510,7 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent)
        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
        envp[0] = devpath_string;
        envp[1] = NULL;
-       error = sysfs_move_dir(kobj, new_parent);
+       error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
        if (error)
                goto out;
        old_parent = kobj->parent;
@@ -726,6 +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.
@@ -931,6 +1004,21 @@ const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
        return kobj_child_ns_ops(kobj->parent);
 }
 
+bool kobj_ns_current_may_mount(enum kobj_ns_type type)
+{
+       bool may_mount = false;
+
+       if (type == KOBJ_NS_TYPE_NONE)
+               return true;
+
+       spin_lock(&kobj_ns_type_lock);
+       if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+           kobj_ns_ops_tbl[type])
+               may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
+       spin_unlock(&kobj_ns_type_lock);
+
+       return may_mount;
+}
 
 void *kobj_ns_grab_current(enum kobj_ns_type type)
 {