driver core: Introduce device_move(): move a device to a new parent.

Provide a function device_move() to move a device to a new parent device. Add
auxilliary functions kobject_move() and sysfs_move_dir().
kobject_move() generates a new uevent of type KOBJ_MOVE, containing the
previous path (DEVPATH_OLD) in addition to the usual values. For this, a new
interface kobject_uevent_env() is created that allows to add further
environmental data to the uevent at the kobject layer.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 74 insertions, 4 deletions

diff --git a/lib/kobject.c b/lib/kobject.c
index 7dd5c0e9d996..744a4b102c7f 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -311,6 +311,56 @@ int kobject_rename(struct kobject * kobj, const char *new_name)
 }
 
 /**
+ *      kobject_move - move object to another parent
+ *      @kobj:  object in question.
+ *      @new_parent: object's new parent
+ */
+
+int kobject_move(struct kobject *kobj, struct kobject *new_parent)
+{
+        int error;
+        struct kobject *old_parent;
+        const char *devpath = NULL;
+        char *devpath_string = NULL;
+        char *envp[2];
+
+        kobj = kobject_get(kobj);
+        if (!kobj)
+                return -EINVAL;
+        new_parent = kobject_get(new_parent);
+        if (!new_parent) {
+                error = -EINVAL;
+                goto out;
+        }
+        /* old object path */
+        devpath = kobject_get_path(kobj, GFP_KERNEL);
+        if (!devpath) {
+                error = -ENOMEM;
+                goto out;
+        }
+        devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
+        if (!devpath_string) {
+                error = -ENOMEM;
+                goto out;
+        }
+        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
+        envp[0] = devpath_string;
+        envp[1] = NULL;
+        error = sysfs_move_dir(kobj, new_parent);
+        if (error)
+                goto out;
+        old_parent = kobj->parent;
+        kobj->parent = new_parent;
+        kobject_put(old_parent);
+        kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+out:
+        kobject_put(kobj);
+        kfree(devpath_string);
+        kfree(devpath);
+        return error;
+}
+
+/**
  *      kobject_del - unlink kobject from hierarchy.
  *      @kobj:  object.
  */
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 7f20e7b857cb..a1922765ff31 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -50,18 +50,22 @@ static char *action_to_string(enum kobject_action action)
                 return "offline";
         case KOBJ_ONLINE:
                 return "online";
+        case KOBJ_MOVE:
+                return "move";
         default:
                 return NULL;
         }
 }
 
 /**
- * kobject_uevent - notify userspace by ending an uevent
+ * kobject_uevent_env - send an uevent with environmental data
  *
- * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
+ * @action: action that is happening (usually KOBJ_MOVE)
  * @kobj: struct kobject that the action is happening to
+ * @envp_ext: pointer to environmental data
  */
-void kobject_uevent(struct kobject *kobj, enum kobject_action action)
+void kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
+                        char *envp_ext[])
 {
         char **envp;
         char *buffer;
@@ -76,6 +80,7 @@ void kobject_uevent(struct kobject *kobj, enum kobject_action action)
         char *seq_buff;
         int i = 0;
         int retval;
+        int j;
 
         pr_debug("%s\n", __FUNCTION__);
 
@@ -134,7 +139,8 @@ void kobject_uevent(struct kobject *kobj, enum kobject_action action)
         scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
         envp [i++] = scratch;
         scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
-
+        for (j = 0; envp_ext && envp_ext[j]; j++)
+                envp[i++] = envp_ext[j];
         /* just reserve the space, overwrite it after kset call has returned */
         envp[i++] = seq_buff = scratch;
         scratch += strlen("SEQNUM=18446744073709551616") + 1;
@@ -200,6 +206,20 @@ exit:
         kfree(envp);
         return;
 }
+
+EXPORT_SYMBOL_GPL(kobject_uevent_env);
+
+/**
+ * kobject_uevent - notify userspace by ending an uevent
+ *
+ * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
+ * @kobj: struct kobject that the action is happening to
+ */
+void kobject_uevent(struct kobject *kobj, enum kobject_action action)
+{
+        kobject_uevent_env(kobj, action, NULL);
+}
+
 EXPORT_SYMBOL_GPL(kobject_uevent);
 
 /**