block: remove REQ_HARDBARRIER

REQ_HARDBARRIER is dead now, so remove the leftovers.  What's left
at this point is:

 - various checks inside the block layer.
 - sanity checks in bio based drivers.
 - now unused bio_empty_barrier helper.
 - Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while,
   but Xen really needs to sort out it's barrier situaton.
 - setting of ordered tags in uas - dead code copied from old scsi
   drivers.
 - scsi different retry for barriers - it's dead and should have been
   removed when flushes were converted to FS requests.
 - blktrace handling of barriers - removed.  Someone who knows blktrace
   better should add support for REQ_FLUSH and REQ_FUA, though.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5027a599077d..aae86fd10c4f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -552,8 +552,7 @@ static inline void blk_clear_queue_full(struct request_queue *q, int sync)
  * it already be started by driver.
  */
 #define RQ_NOMERGE_FLAGS        \
-        (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER | \
-         REQ_FLUSH | REQ_FUA)
+        (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
 #define rq_mergeable(rq)        \
         (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
          (((rq)->cmd_flags & REQ_DISCARD) || \