On Tue, Aug 23, 2022 at 11:50:05PM +0900, Suwan Kim wrote:
> @@ -409,6 +409,8 @@ static bool virtblk_add_req_batch(struct virtio_blk_vq *vq,
> virtblk_unmap_data(req, vbr);
> virtblk_cleanup_cmd(req);
> rq_list_add(requeue_list, req);
> + } else {
> + blk_mq_start_request(req);
> }
The device may see new requests as soon as virtblk_add_req() is called
above. Therefore the device may complete the request before
blk_mq_start_request() is called.
rq->io_start_time_ns = ktime_get_ns() will be after the request was
actually submitted.
I think blk_mq_start_request() needs to be called before
virtblk_add_req().
Stefan
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