block: simplify empty barrier implementation

Empty barrier required special handling in __elv_next_request() to
complete it without letting the low level driver see it.

With previous changes, barrier code is now flexible enough to skip the
BAR step using the same barrier sequence selection mechanism.  Drop
the special handling and mask off q->ordered from start_ordered().

Remove blk_empty_barrier() test which now has no user.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Tejun Heo 2008-11-28 13:32:06 +09:00 committed by Jens Axboe
parent 8f11b3e99a
commit 58eea927d2
3 changed files with 10 additions and 15 deletions

View file

@ -596,7 +596,6 @@ enum {
#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
#define blk_discard_rq(rq) ((rq)->cmd_flags & REQ_DISCARD)
#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
#define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
/* rq->queuelist of dequeued request must be list_empty() */
#define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))