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>
diff --git a/block/blk-core.c b/block/blk-core.c
index 4ce953f..fc7d8ad 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -136,7 +136,7 @@
{
struct request_queue *q = rq->q;
- if (&q->flush_rq != rq) {
+ if (!(rq->cmd_flags & REQ_FLUSH_SEQ)) {
if (error)
clear_bit(BIO_UPTODATE, &bio->bi_flags);
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
@@ -1789,7 +1789,7 @@
* normal IO on queueing nor completion. Accounting the
* containing request is enough.
*/
- if (blk_do_io_stat(req) && req != &req->q->flush_rq) {
+ if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) {
unsigned long duration = jiffies - req->start_time;
const int rw = rq_data_dir(req);
struct hd_struct *part;
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 54b123d..8592869 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -130,6 +130,7 @@
BUG();
}
+ rq->cmd_flags |= REQ_FLUSH_SEQ;
elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
return rq;
}
diff --git a/block/blk.h b/block/blk.h
index 2db8f32..9d2ee8f 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -61,7 +61,7 @@
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)