From: Michael S. Tsirkin <mst@redhat.com>
Date: Sun, 9 Nov 2014 23:04:29 +0000 (+1030)
Subject: virtio_blk: fix race at module removal
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=46652a861b46cc62e9d983d5cf6d9532cd6fccab;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

virtio_blk: fix race at module removal

If a device appears while module is being removed,
driver will get a callback after we've given up
on the major number.

In theory this means this major number can get reused
by something else, resulting in a conflict.

To fix, cleanup in reverse order of initialization.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index c6a27d54ad62..ce848ac1e9a6 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -871,8 +871,8 @@ out_destroy_workqueue:
 
 static void __exit fini(void)
 {
-	unregister_blkdev(major, "virtblk");
 	unregister_virtio_driver(&virtio_blk);
+	unregister_blkdev(major, "virtblk");
 	destroy_workqueue(virtblk_wq);
 }
 module_init(init);