On Tue, Mar 26, 2019 at 9:18 AM jianchao.wang <jianchao.w.wang@xxxxxxxxxx> wrote: > > Hi Keith > > On 3/25/19 9:49 PM, Keith Busch wrote: > > On Mon, Mar 25, 2019 at 01:38:37PM +0800, Jianchao Wang wrote: > >> blk_mq_tagset_inflight_iter is not safe that it could get stale request > >> in tags->rqs[]. Use blk_mq_queue_tag_inflight_iter here. A new helper > >> interface nvme_iterate_inflight_rqs is introduced to iterate > >> all of the ns under a ctrl. > > > > Nak, NVMe only iterates tags when new requests can't enter, allocated > > requests can't dispatch, and dispatched commands can't complete. So > > it is perfectly safe to iterate if the driver takes reasonable steps > > beforehand. > > nvme_dev_disable just quiesce and freeze the request_queue, but not drain the enters. > So there still could be someone escapes the queue freeze checking and tries to allocate > request. The rq->state is just IDLE for these allocated request, so there shouldn't be issue in NVMe's case. Thanks, Ming
