23673ca740
This allows a front-end to request for a callback when the backend is writable again. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Message-id: 96f93c0f741064604bbb6389ce962191120af8b7.1362505276.git.amit.shah@redhat.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>