block: add a blk_account_io_merge_bio helper
Move the non-"new_io" branch of blk_account_io_start() into separate
function. Fix merge accounting for discards (they were counted as write
merges).
The new blk_account_io_merge_bio() doesn't call update_io_ticks() unlike
blk_account_io_start(), as there is no reason for that.
[hch: rebased]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk.h b/block/blk.h
index 0ecba2a..428f7e5 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -185,7 +185,7 @@ bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
unsigned int nr_segs, struct request **same_queue_rq);
-void blk_account_io_start(struct request *req, bool new_io);
+void blk_account_io_start(struct request *req);
void blk_account_io_done(struct request *req, u64 now);
/*