block: simplify I/O stat accounting

This simplifies I/O stat accounting switching code and separates it
completely from I/O scheduler switch code.

Requests are accounted according to the state of their request queue
at the time of the request allocation. There is no need anymore to
flush the request queue when switching I/O accounting state.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/block/blk.h b/block/blk.h
index 5dfc41267a08..79c85f7c9ff5 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -114,12 +114,7 @@ static inline int blk_cpu_to_group(int cpu)
 
 static inline int blk_do_io_stat(struct request *rq)
 {
-        struct gendisk *disk = rq->rq_disk;
-
-        if (!disk || !disk->queue)
-                return 0;
-
-        return blk_queue_io_stat(disk->queue) && (rq->cmd_flags & REQ_ELVPRIV);
+        return rq->rq_disk && blk_rq_io_stat(rq);
 }
 
 #endif