From b70f5fa043b318659c936d8c3c696250e6528944 Mon Sep 17 00:00:00 2001
From: Daniel Stodden <daniel.stodden@citrix.com>
Date: Fri, 30 Apr 2010 22:01:19 +0000
Subject: [PATCH] blkfront: Lock blkfront_info when closing

The bdev .open/.release fops race against backend switches to Closing,
handled by the XenBus thread.

The original code attempted to serialize block device holders and
xenbus only via bd_mutex. This is insufficient, the info->bd pointer
may already be stale (or null) while xenbus tries to bump up the
refcount.

Protect blkfront_info with a dedicated mutex.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
Reading git-format-patch failed