block: add REQ_FLUSH_SEQ

rq == &q->flush_rq was used to determine whether a rq is part of a
flush sequence, which worked because all requests in a flush sequence
were sequenced using the single dedicated request.  This is about to
change, so introduce REQ_FLUSH_SEQ flag to distinguish flush sequence
requests.

This patch doesn't cause any behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/blk.h b/block/blk.h
index 2db8f32838e7..9d2ee8f4d9af 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -61,7 +61,7 @@ static inline struct request *__elv_next_request(struct request_queue *q)
                 while (!list_empty(&q->queue_head)) {
                         rq = list_entry_rq(q->queue_head.next);
                         if (!(rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) ||
-                            rq == &q->flush_rq)
+                            (rq->cmd_flags & REQ_FLUSH_SEQ))
                                 return rq;
                         rq = blk_do_flush(q, rq);
                         if (rq)