+ level[len] = 0;
+
+ request_module("md-%s", level);
+ spin_lock(&pers_lock);
+ pers = find_pers(LEVEL_NONE, level);
+ if (!pers || !try_module_get(pers->owner)) {
+ spin_unlock(&pers_lock);
+ printk(KERN_WARNING "md: personality %s not loaded\n", level);
+ return -EINVAL;
+ }
+ spin_unlock(&pers_lock);
+
+ if (pers == mddev->pers) {
+ /* Nothing to do! */
+ module_put(pers->owner);
+ return rv;
+ }
+ if (!pers->takeover) {
+ module_put(pers->owner);
+ printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
+ mdname(mddev), level);
+ return -EINVAL;
+ }
+
+ /* ->takeover must set new_* and/or delta_disks
+ * if it succeeds, and may set them when it fails.
+ */
+ priv = pers->takeover(mddev);
+ if (IS_ERR(priv)) {
+ mddev->new_level = mddev->level;
+ mddev->new_layout = mddev->layout;
+ mddev->new_chunk = mddev->chunk_size;
+ mddev->raid_disks -= mddev->delta_disks;
+ mddev->delta_disks = 0;
+ module_put(pers->owner);
+ printk(KERN_WARNING "md: %s: %s would not accept array\n",
+ mdname(mddev), level);
+ return PTR_ERR(priv);
+ }
+
+ /* Looks like we have a winner */
+ mddev_suspend(mddev);
+ mddev->pers->stop(mddev);
+ module_put(mddev->pers->owner);
+ mddev->pers = pers;
+ mddev->private = priv;
+ strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
+ mddev->level = mddev->new_level;
+ mddev->layout = mddev->new_layout;
+ mddev->chunk_size = mddev->new_chunk;
+ mddev->delta_disks = 0;
+ pers->run(mddev);
+ mddev_resume(mddev);
+ set_bit(MD_CHANGE_DEVS, &mddev->flags);
+ set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+ md_wakeup_thread(mddev->thread);