virtio_blk: drop REQ_HARDBARRIER support

Remove now unused REQ_HARDBARRIER support.  virtio_blk already
supports REQ_FLUSH and the usefulness of REQ_FUA for virtio_blk is
questionable at this point, so there's nothing else to do to support
new REQ_FLUSH/FUA interface.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 4 insertions, 13 deletions

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index d10b635b3946..126062802cb7 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -128,9 +128,6 @@ static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
                 }
         }
 
-        if (vbr->req->cmd_flags & REQ_HARDBARRIER)
-                vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
-
         sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
 
         /*
@@ -388,13 +385,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
         vblk->disk->driverfs_dev = &vdev->dev;
         index++;
 
-        /*
-         * 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; otherwise, we must assume
-         * that the host does not perform any kind of volatile write
-         * caching.
-         */
+        /* configure queue flush support */
         if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
                 blk_queue_flush(q, REQ_FLUSH);
 
@@ -515,9 +506,9 @@ static const struct virtio_device_id id_table[] = {
 };
 
 static unsigned int features[] = {
-        VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
-        VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
-        VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
+        VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
+        VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
+        VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY
 };
 
 /*