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, 3 deletions

diff --git a/block/blk.h b/block/blk.h
index 2a0ea32d249f..ca51543b248c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -171,14 +171,13 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
  *
  *      a) it's attached to a gendisk, and
  *      b) the queue had IO stats enabled when this request was started, and
- *      c) it's a file system request or a discard request
+ *      c) it's a file system request
  */
 static inline int blk_do_io_stat(struct request *rq)
 {
         return rq->rq_disk &&
                (rq->cmd_flags & REQ_IO_STAT) &&
-               (rq->cmd_type == REQ_TYPE_FS ||
-                (rq->cmd_flags & REQ_DISCARD));
+                (rq->cmd_type == REQ_TYPE_FS);
 }
 
 /*