I/O accounting buckets I/O into the read/write/discard categories into
which passthrough I/O does not fit at all. It also accounts to the
block_device, which may not even exist for passthrough I/O.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
block/blk-mq.c | 11 ++++++++---
block/blk.h | 2 +-
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a05ce77250316..ab4b646551334 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -883,10 +883,15 @@ static inline void blk_account_io_done(struct request *req, u64 now)
static void __blk_account_io_start(struct request *rq)
{
- /* passthrough requests can hold bios that do not have ->bi_bdev set */
- if (rq->bio && rq->bio->bi_bdev)
+ /*
+ * All non-passthrough requests are created from a bio with one
+ * exception: when a flush command that is part of a flush sequence
+ * generated by the state machine in blk-flush.c is cloned onto the
+ * lower device by dm-multipath we can get here without a bio.
+ */
+ if (rq->bio)
rq->part = rq->bio->bi_bdev;
- else if (rq->q->disk)
+ else
rq->part = rq->q->disk->part0;
part_stat_lock();
diff --git a/block/blk.h b/block/blk.h
index ebaa59ca46ca6..6f21859c7f0ff 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -325,7 +325,7 @@ int blk_dev_init(void);
*/
static inline bool blk_do_io_stat(struct request *rq)
{
- return (rq->rq_flags & RQF_IO_STAT) && rq->q->disk;
+ return (rq->rq_flags & RQF_IO_STAT) && !blk_rq_is_passthrough(rq);
}
void update_io_ticks(struct block_device *part, unsigned long now, bool end);
--
2.30.2
