tree 7c23c2c86ca96f0a1b3dcbb86c70d5989e156710
parent 9ef91a677110ec200d7b2904fc4bcae5a77329ad
author Christoph Hellwig <hch@lst.de> 1250780315 +0200
committer Anthony Liguori <aliguori@us.ibm.com> 1251423022 -0500

raw-posix: add Linux native AIO support

Now that do have a nicer interface to work against we can add Linux native
AIO support.  It's an extremly thing layer just setting up an iocb for
the io_submit system call in the submission path, and registering an
eventfd with the qemu poll handler to do complete the iocbs directly
from there.

This started out based on Anthony's earlier AIO patch, but after
estimated 42,000 rewrites and just as many build system changes
there's not much left of it.

To enable native kernel aio use the aio=native sub-command on the
drive command line.  I have also added an option to qemu-io to
test the aio support without needing a guest.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>