Re: [PATCH] virtio-blk: Fix WARN_ON_ONCE in virtio_queue_rq()
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: 2022-08-23 20:57:00
Also in:
linux-block
On Tue, Aug 23, 2022 at 11:50:05PM +0900, Suwan Kim wrote:
quoted hunk
@@ -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