Move the dma helpers to a private aio pool, and implement a cancellation
method for them.  Should prevent issues when cancelling I/O while dma is
in progress.
Signed-off-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6872 c046a42c-6fe2-441c-8c8c-71466251a162