Do not allow userspace to block or reset the ring until the device has been
configured. This will prevent the bug where userspace can write to those
files and access mb_addr before it has been setup.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>