[PATCH 0/4] Various blktap related patches (xen part)

[Kevin Wolf <kwolf@suse.de>]

The following patch series is the xen repository part of some blktap
related patches that accumulated during SLES 11 development. A qemu-xen
part will follow once these are checked in, so the dependencies are met.

The main point is restoring the possibility to use qemu-dm as a backend
for blktap devices (and mid-term letting tapdisk die with its duplicated
code), but at least the error handling addresses general concerns.

As an overview, we have the following patches:

1) blktapctrl: Select backend by prefix
2) blktap: Export disk type constants for ioemu
3) blktapctrl: Fix too early close of pipes
4) blktap: Move error signaling to blktapctrl

Kevin