blk-mq: use ->bi_bdev for I/O accounting
Remove the reverse map from a sector to a partition for I/O accounting by
simply using ->bi_bdev.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index 9315311..6dfbdde 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1298,7 +1298,11 @@ void blk_account_io_start(struct request *rq)
if (!blk_do_io_stat(rq))
return;
- rq->part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
+ /* passthrough requests can hold bios that do not have ->bi_bdev set */
+ if (rq->bio && rq->bio->bi_bdev)
+ rq->part = rq->bio->bi_bdev;
+ else
+ rq->part = rq->rq_disk->part0;
part_stat_lock();
update_io_ticks(rq->part, jiffies, false);