nbd: fix memory leak of nbd_dev array

We leak the memory allocated for the nbd_dev array at multiple places.
Fix them by either adding a kfree() or by rearranging code to return
before we allocate the memory.
Signed-off-by: NSven Wegener <sven.wegener@stealer.net>
Cc: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/block/nbd.c

@@ -707,15 +707,15 @@ static int __init nbd_init(void)
 
 	BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
 
-	nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
-	if (!nbd_dev)
-		return -ENOMEM;
-
 	if (max_part < 0) {
 		printk(KERN_CRIT "nbd: max_part must be >= 0\n");
 		return -EINVAL;
 	}
 
+	nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
+	if (!nbd_dev)
+		return -ENOMEM;
+
 	part_shift = 0;
 	if (max_part > 0)
 		part_shift = fls(max_part);
@@ -779,6 +779,7 @@ static int __init nbd_init(void)
 		blk_cleanup_queue(nbd_dev[i].disk->queue);
 		put_disk(nbd_dev[i].disk);
 	}
+	kfree(nbd_dev);
 	return err;
 }
 
@@ -795,6 +796,7 @@ static void __exit nbd_cleanup(void)
 		}
 	}
 	unregister_blkdev(NBD_MAJOR, "nbd");
+	kfree(nbd_dev);
 	printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
 }