xen-blkfront: plug device number leak in xlblk_init() error path

... though after a failed xenbus_register_frontend() all may be lost.

Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8bf0cb7b2565..773da7d6491e 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1450,6 +1450,8 @@ static struct xenbus_driver blkfront = {
 
 static int __init xlblk_init(void)
 {
+        int ret;
+
         if (!xen_domain())
                 return -ENODEV;
 
@@ -1459,7 +1461,13 @@ static int __init xlblk_init(void)
                 return -ENODEV;
         }
 
-        return xenbus_register_frontend(&blkfront);
+        ret = xenbus_register_frontend(&blkfront);
+        if (ret) {
+                unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
+                return ret;
+        }
+
+        return 0;
 }
 module_init(xlblk_init);