[PATCH 1/2] barrier-test: Do not flush delayed queue for reads

[Jan Kara <jack@suse.cz>]

Signed-off-by: Jan Kara <jack@suse.cz>
---
 block/barrier-test-iosched.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/block/barrier-test-iosched.c b/block/barrier-test-iosched.c
index f641537..8c30461 100644
--- a/block/barrier-test-iosched.c
+++ b/block/barrier-test-iosched.c
@@ -78,8 +78,6 @@ struct barrier_test_data {
 	int total_barriers;
 };
 
-typedef void (rq_end_io_fn)(struct request *, int);
-
 /*
  * wb_requests are ones that we are pretending are done.  We
  * just return completion right away to the poor user.
@@ -429,7 +427,23 @@ static void barrier_test_add_request(struct request_queue *q, struct request *rq
 	 * reads only happen after all the writeback io is complete.
 	 */
 	if (!(rq->cmd_flags & REQ_WRITE)) {
-		if (atomic_read(&nd->pending_rqs)) {
+		struct request *wrq;
+		bool overlap = false;
+
+		list_for_each_entry(wrq, &nd->delayed_requests, queuelist) {
+			if (blk_rq_pos(wrq) <= blk_rq_pos(rq) &&
+			    blk_rq_pos(wrq) + blk_rq_sectors(wrq) >
+							blk_rq_pos(rq)) {
+				overlap = true;
+				break;
+			} else if (blk_rq_pos(wrq) >= blk_rq_pos(rq) &&
+				   blk_rq_pos(wrq) <
+					blk_rq_pos(rq) + blk_rq_sectors(rq)) {
+				overlap = true;
+				break;
+			}
+		}
+		if (overlap) {
 			queue_all_delayed(nd, 0);
 			list_add_tail(&rq->queuelist, &nd->reads_waiting_flush);
 		} else {
-- 
1.7.1