From: Daniel Stodden <daniel.stodden@citrix.com>
Date: Fri, 30 Apr 2010 22:01:19 +0000 (+0000)
Subject: blkfront: Lock blkfront_info when closing
X-Git-Tag: v2.6.36-rc1~288^2~71
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b70f5fa043b318659c936d8c3c696250e6528944;p=pandora-kernel.git

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-diff-tree failed