block: Clean up special command handling logic

Remove special-casing of non-rw fs style requests (discard). The nomerge
flags are consolidated in blk_types.h, and rq_mergeable() and
bio_mergeable() have been modified to use them.

bio_is_rw() is used in place of bio_has_data() a few places. This is
done to to distinguish true reads and writes from other fs type requests
that carry a payload (e.g. write same).

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 2 insertions, 4 deletions

diff --git a/block/elevator.c b/block/elevator.c
index 6a55d418896f..9b1d42b62f20 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -562,8 +562,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
 
         if (rq->cmd_flags & REQ_SOFTBARRIER) {
                 /* barriers are scheduling boundary, update end_sector */
-                if (rq->cmd_type == REQ_TYPE_FS ||
-                    (rq->cmd_flags & REQ_DISCARD)) {
+                if (rq->cmd_type == REQ_TYPE_FS) {
                         q->end_sector = rq_end_sector(rq);
                         q->boundary_rq = rq;
                 }
@@ -605,8 +604,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
                 if (elv_attempt_insert_merge(q, rq))
                         break;
         case ELEVATOR_INSERT_SORT:
-                BUG_ON(rq->cmd_type != REQ_TYPE_FS &&
-                       !(rq->cmd_flags & REQ_DISCARD));
+                BUG_ON(rq->cmd_type != REQ_TYPE_FS);
                 rq->cmd_flags |= REQ_SORTED;
                 q->nr_sorted++;
                 if (rq_mergeable(rq)) {