unregister_blkdev(): return void

Put WARN_ON and fixed all callers of unregister_blkdev().  Now we can make
unregister_blkdev return void.

Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/block/genhd.c b/block/genhd.c
index 7f71b2c..3af1e7a 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -108,13 +108,11 @@
 
 EXPORT_SYMBOL(register_blkdev);
 
-/* todo: make void - error printk here */
-int unregister_blkdev(unsigned int major, const char *name)
+void unregister_blkdev(unsigned int major, const char *name)
 {
 	struct blk_major_name **n;
 	struct blk_major_name *p = NULL;
 	int index = major_to_index(major);
-	int ret = 0;
 
 	mutex_lock(&block_subsys_lock);
 	for (n = &major_names[index]; *n; n = &(*n)->next)
@@ -122,15 +120,12 @@
 			break;
 	if (!*n || strcmp((*n)->name, name)) {
 		WARN_ON(1);
-		ret = -EINVAL;
 	} else {
 		p = *n;
 		*n = p->next;
 	}
 	mutex_unlock(&block_subsys_lock);
 	kfree(p);
-
-	return ret;
 }
 
 EXPORT_SYMBOL(unregister_blkdev);