- if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) {
- /*
- * If the FLUSH feature is supported we do have support for
- * flushing a volatile write cache on the host. Use that
- * to implement write barrier support.
- */
- blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH);
- } else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) {
- /*
- * If the BARRIER feature is supported the host expects us
- * to order request by tags. This implies there is not
- * volatile write cache on the host, and that the host
- * never re-orders outstanding I/O. This feature is not
- * useful for real life scenarious and deprecated.
- */
- blk_queue_ordered(q, QUEUE_ORDERED_TAG);
- } else {
- /*
- * If the FLUSH feature is not supported we must assume that
- * the host does not perform any kind of volatile write
- * caching. We still need to drain the queue to provider
- * proper barrier semantics.
- */
- blk_queue_ordered(q, QUEUE_ORDERED_DRAIN);
- }
+ /* configure queue flush support */
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
+ blk_queue_flush(q, REQ_FLUSH);