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, 5 insertions, 13 deletions

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 1de30eb83bb..f3cf924a2cd 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -320,19 +320,11 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
                                     "changed. The Linux SCSI layer does not "
                                     "automatically adjust these parameters.\n");
 
-                if (scmd->request->cmd_flags & REQ_HARDBARRIER)
-                        /*
-                         * barrier requests should always retry on UA
-                         * otherwise block will get a spurious error
-                         */
-                        return NEEDS_RETRY;
-                else
-                        /*
-                         * for normal (non barrier) commands, pass the
-                         * UA upwards for a determination in the
-                         * completion functions
-                         */
-                        return SUCCESS;
+                /*
+                 * Pass the UA upwards for a determination in the completion
+                 * functions.
+                 */
+                return SUCCESS;
 
                 /* these three are not supported */
         case COPY_ABORTED: